Bitfield addresses cannot be passed around in a pointer. This makes it
hard to use parse-options to set/unset them. Turn this struct to
normal integers. This of course increases the size of this struct
multiple times, but since we only have a handful of diff_options
variables around, memory consumption is not at all a concern.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This changes the error handling for the options --color-moved-ws
and --color-moved-ws to be like the rest of the options.
Move the die() call out of parse_color_moved_ws into the parsing
of command line options. As the function returns a bit field, change
its signature to return an unsigned instead of an int; add a new bit
to signal errors. Once the error is signaled, we discard the other
bits, such that it doesn't matter if the error bit overlaps with any
other bit.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Various codepaths in the core-ish part learn to work on an
arbitrary in-core index structure, not necessarily the default
instance "the_index".
* nd/the-index: (23 commits)
revision.c: reduce implicit dependency the_repository
revision.c: remove implicit dependency on the_index
ws.c: remove implicit dependency on the_index
tree-diff.c: remove implicit dependency on the_index
submodule.c: remove implicit dependency on the_index
line-range.c: remove implicit dependency on the_index
userdiff.c: remove implicit dependency on the_index
rerere.c: remove implicit dependency on the_index
sha1-file.c: remove implicit dependency on the_index
patch-ids.c: remove implicit dependency on the_index
merge.c: remove implicit dependency on the_index
merge-blobs.c: remove implicit dependency on the_index
ll-merge.c: remove implicit dependency on the_index
diff-lib.c: remove implicit dependency on the_index
read-cache.c: remove implicit dependency on the_index
diff.c: remove implicit dependency on the_index
grep.c: remove implicit dependency on the_index
diff.c: remove the_index dependency in textconv() functions
blame.c: rename "repo" argument to "r"
combine-diff.c: remove implicit dependency on the_index
...
[jc: squashed in missing forward decl in userdiff.h found by Ramsay]
Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new variant repo_diff_setup() is added that takes 'struct repository *'
and diff_setup() becomes a thin macro around it that is protected by
NO_THE_REPOSITORY_COMPATIBILITY_MACROS, similar to NO_THE_INDEX_....
The plan is these macros will always be defined for all library files
and the macros are only accessible in builtin/
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff and textconv code has so widespread use that it's hard to simply
update their api and all call sites at once because it would result in
a big patch. For now reduce the_index references to two places:
diff_setup() and fill_textconv().
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The color output support for recently introduced "range-diff"
command got tweaked a bit.
* sb/range-diff-colors:
range-diff: indent special lines as context
range-diff: make use of different output indicators
diff.c: add --output-indicator-{new, old, context}
diff.c: rewrite emit_line_0 more understandably
diff.c: omit check for line prefix in emit_line_0
diff: use emit_line_0 once per line
diff.c: add set_sign to emit_line_0
diff.c: reorder arguments for emit_line_ws_markup
diff.c: simplify caller of emit_line_0
t3206: add color test for range-diff --dual-color
test_decode_color: understand FAINT and ITALIC
This will prove useful in range-diff in a later patch as we will be able to
differentiate between adding a new file (that line is starting with +++
and then the file name) and regular new lines.
It could also be useful for experimentation in new patch formats, i.e.
we could teach git to emit moved lines with lines other than +/-.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git tbdiff" that lets us compare individual patches in two
iterations of a topic has been rewritten and made into a built-in
command.
* js/range-diff: (21 commits)
range-diff: use dim/bold cues to improve dual color mode
range-diff: make --dual-color the default mode
range-diff: left-pad patch numbers
completion: support `git range-diff`
range-diff: populate the man page
range-diff --dual-color: skip white-space warnings
range-diff: offer to dual-color the diffs
diff: add an internal option to dual-color diffs of diffs
color: add the meta color GIT_COLOR_REVERSE
range-diff: use color for the commit pairs
range-diff: add tests
range-diff: do not show "function names" in hunk headers
range-diff: adjust the output of the commit pairs
range-diff: suppress the diff headers
range-diff: indent the diffs just like tbdiff
range-diff: right-trim commit messages
range-diff: also show the diff between patches
range-diff: improve the order of the shown commits
range-diff: first rudimentary implementation
Introduce `range-diff` to compare iterations of a topic branch
...
This code is only needed for diff-tree (since f0c6b2a2fd ([PATCH]
Optimize diff-tree -[CM] --stdin - 2005-05-27)). Let the caller do the
preparation instead and avoid read_index() in diff.c code.
read_index() should be avoided (in addition to the_index) because it
uses get_index_file() underneath to get the path $GIT_DIR/index. This
effectively pulls the_repository in and may become the only reason to
pull a 'struct repository *' in diff.c. Let's keep the dependencies as
few as possible and kick it back to diff-tree.c
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It *is* a confusing thing to look at a diff of diffs. All too easy is it
to mix up whether the -/+ markers refer to the "inner" or the "outer"
diff, i.e. whether a `+` indicates that a line was added by either the
old or the new diff (or both), or whether the new diff does something
different than the old diff.
To make things easier to process for normal developers, we introduced
the dual color mode which colors the lines according to the commit diff,
i.e. lines that are added by a commit (whether old, new, or both) are
colored in green. In non-dual color mode, the lines would be colored
according to the outer diff: if the old commit added a line, it would be
colored red (because that line addition is only present in the first
commit range that was specified on the command-line, i.e. the "old"
commit, but not in the second commit range, i.e. the "new" commit).
However, this dual color mode is still not making things clear enough,
as we are looking at two levels of diffs, and we still only pick a color
according to *one* of them (the outer diff marker is colored
differently, of course, but in particular with deep indentation, it is
easy to lose track of that outer diff marker's background color).
Therefore, let's add another dimension to the mix. Still use
green/red/normal according to the commit diffs, but now also dim the
lines that were only in the old commit, and use bold face for the lines
that are only in the new commit.
That way, it is much easier not to lose track of, say, when we are
looking at a line that was added in the previous iteration of a patch
series but the new iteration adds a slightly different version: the
obsolete change will be dimmed, the current version of the patch will be
bold.
At least this developer has a much easier time reading the range-diffs
that way.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When diffing diffs, it can be quite daunting to figure out what the heck
is going on, as there are nested +/- signs.
Let's make this easier by adding a flag in diff_options that allows
color-coding the outer diff sign with inverted colors, so that the
preimage and postimage is colored like the diff it is.
Of course, this really only makes sense when the preimage and postimage
*are* diffs. So let's not expose this flag via a command-line option for
now.
This is a feature that was invented by git-tbdiff, and it will be used
by `git range-diff` in the next commit, by offering it via a new option:
`--dual-color`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When showing the diff between corresponding patches of the two branch
versions, we have to make up a fake filename to run the diff machinery.
That filename does not carry any meaningful information, hence tbdiff
suppresses it. So we should, too.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff --color-moved" feature has further been tweaked.
* sb/diff-color-move-more:
diff.c: offer config option to control ws handling in move detection
diff.c: add white space mode to move detection that allows indent changes
diff.c: factor advance_or_nullify out of mark_color_as_moved
diff.c: decouple white space treatment from move detection algorithm
diff.c: add a blocks mode for moved code detection
diff.c: adjust hash function signature to match hashmap expectation
diff.c: do not pass diff options as keydata to hashmap
t4015: avoid git as a pipe input
xdiff/xdiffi.c: remove unneeded function declarations
xdiff/xdiff.h: remove unused flags
The option of --color-moved has proven to be useful as observed on the
mailing list. However when refactoring sometimes the indentation changes,
for example when partitioning a functions into smaller helper functions
the code usually mostly moved around except for a decrease in indentation.
To just review the moved code ignoring the change in indentation, a mode
to ignore spaces in the move detection as implemented in a previous patch
would be enough. However the whole move coloring as motivated in commit
2e2d5ac (diff.c: color moved lines differently, 2017-06-30), brought
up the notion of the reviewer being able to trust the move of a "block".
As there are languages such as python, which depend on proper relative
indentation for the control flow of the program, ignoring any white space
change in a block would not uphold the promises of 2e2d5ac that allows
reviewers to pay less attention to the inside of a block, as inside
the reviewer wants to assume the same program flow.
This new mode of white space ignorance will take this into account and will
only allow the same white space changes per line in each block. This patch
even allows only for the same change at the beginning of the lines.
As this is a white space mode, it is made exclusive to other white space
modes in the move detection.
This patch brings some challenges, related to the detection of blocks.
We need a wide net to catch the possible moved lines, but then need to
narrow down to check if the blocks are still intact. Consider this
example (ignoring block sizes):
- A
- B
- C
+ A
+ B
+ C
At the beginning of a block when checking if there is a counterpart
for A, we have to ignore all space changes. However at the following
lines we have to check if the indent change stayed the same.
Checking if the indentation change did stay the same, is done by computing
the indentation change by the difference in line length, and then assume
the change is only in the beginning of the longer line, the common tail
is the same. That is why the test contains lines like:
- <TAB> A
...
+ A <TAB>
...
As the first line starting a block is caught using a compare function that
ignores white spaces unlike the rest of the block, where the white space
delta is taken into account for the comparison, we also have to think about
the following situation:
- A
- B
- A
- B
+ A
+ B
+ A
+ B
When checking if the first A (both in the + and - lines) is a start of
a block, we have to check all 'A' and record all the white space deltas
such that we can find the example above to be just one block that is
indented.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the original implementation of the move detection logic the choice for
ignoring white space changes is the same for the move detection as it is
for the regular diff. Some cases came up where different treatment would
have been nice.
Allow the user to specify that white space should be ignored differently
during detection of moved lines than during generation of added and removed
lines. This is done by providing analogs to the --ignore-space-at-eol,
-b, and -w options by introducing the option --color-moved-ws=<modes>
with the modes named "ignore-space-at-eol", "ignore-space-change" and
"ignore-all-space", which is used only during the move detection phase.
As we change the default, we'll adjust the tests.
For now we do not infer any options to treat white spaces in the move
detection from the generic white space options given to diff.
This can be tuned later to reasonable default.
As we plan on adding more white space related options in a later patch,
that interferes with the current white space options, use a flag field
and clamp it down to XDF_WHITESPACE_FLAGS, as that (a) allows to easily
check at parse time if we give invalid combinations and (b) can reuse
parts of this patch.
By having the white space treatment in its own option, we'll also
make it easier for a later patch to have an config option for
spaces in the move detection.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The new "blocks" mode provides a middle ground between plain and zebra.
It is as intuitive (few colors) as plain, but still has the requirement
for a minimum of lines/characters to count a block as moved.
Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
(https://public-inbox.org/git/87o9j0uljo.fsf@evledraar.gmail.com/)
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the ability to control rename detection for merge via a config setting.
This setting behaves the same and defaults to the value of diff.renames but only
applies to merge.
Reviewed-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Ben Peart <benpeart@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff" and friends learned "--compact-summary" that shows the
information usually given with the "--summary" option on the same
line as the diffstat output of the "--stat" option (which saves
vertical space and keeps info on a single path at the same place).
* nd/diff-stat-with-summary:
diff: add --compact-summary
diff.c: refactor pprint_rename() to use strbuf
Certain information is currently shown with --summary, but when used
in combination with --stat it's a bit hard to read since info of the
same file is in two places (--stat and --summary).
On top of that, commits that add or remove files double the number of
display lines, which could be a lot if you add or remove a lot of
files.
--compact-summary embeds most of --summary back in --stat in the
little space between the file name part and the graph line, e.g. with
commit 0433d533f1:
Documentation/merge-config.txt | 4 +
builtin/merge.c | 2 +
...-pull-verify-signatures.sh (new +x) | 81 ++++++++++++++
t/t7612-merge-verify-signatures.sh | 45 ++++++++
4 files changed, 132 insertions(+)
It helps both condensing information and saving some text
space. What's new in diffstat is:
- A new 0644 file is shown as (new)
- A new 0755 file is shown as (new +x)
- A new symlink is shown as (new +l)
- A deleted file is shown as (gone)
- A mode change adding executable bit is shown as (mode +x)
- A mode change removing it is shown as (mode -x)
Note that --compact-summary does not contain all the information
--summary provides. Rewrite percentage is not shown but it could be
added later, like R50% or C20%.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"diff" family of commands learned "--find-object=<object-id>" option
to limit the findings to changes that involve the named object.
* sb/diff-blobfind-pickaxe:
diff: use HAS_MULTI_BITS instead of counting bits manually
diff: properly error out when combining multiple pickaxe options
diffcore: add a pickaxe option to find a specific blob
diff: introduce DIFF_PICKAXE_KINDS_MASK
diff: migrate diff_flags.pickaxe_ignore_case to a pickaxe_opts bit
diff.h: make pickaxe_opts an unsigned bit field
Sometimes users are given a hash of an object and they want to
identify it further (ex.: Use verify-pack to find the largest blobs,
but what are these? or [1])
One might be tempted to extend git-describe to also work with blobs,
such that `git describe <blob-id>` gives a description as
'<commit-ish>:<path>'. This was implemented at [2]; as seen by the sheer
number of responses (>110), it turns out this is tricky to get right.
The hard part to get right is picking the correct 'commit-ish' as that
could be the commit that (re-)introduced the blob or the blob that
removed the blob; the blob could exist in different branches.
Junio hinted at a different approach of solving this problem, which this
patch implements. Teach the diff machinery another flag for restricting
the information to what is shown. For example:
$ ./git log --oneline --find-object=v2.0.0:Makefile
b2feb64309 Revert the whole "ask curl-config" topic for now
47fbfded53 i18n: only extract comments marked with "TRANSLATORS:"
we observe that the Makefile as shipped with 2.0 was appeared in
v1.9.2-471-g47fbfded53 and in v2.0.0-rc1-5-gb2feb6430b. The
reason why these commits both occur prior to v2.0.0 are evil
merges that are not found using this new mechanism.
[1] https://stackoverflow.com/questions/223678/which-commit-has-this-blob
[2] https://public-inbox.org/git/20171028004419.10139-1-sbeller@google.com/
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently the check whether to perform pickaxing is done via checking
`diffopt->pickaxe`, which contains the command line argument that we
want to pickaxe for. Soon we'll introduce a new type of pickaxing, that
will not store anything in the `.pickaxe` field, so let's migrate the
check to be dependent on pickaxe_opts.
It is not enough to just replace the check for pickaxe by pickaxe_opts,
because flags might be set, but pickaxing was not requested ('-i').
To cope with that, introduce a mask to check only for the bits indicating
the modes of operation.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently flags for pickaxing are found in different places. Unify the
flags into the `pickaxe_opts` field, which will contain any pickaxe related
flags.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This variable is used as a bit field[1], and as we are about to add more
fields, indicate its usage as a bit field by making it unsigned.
[1] containing the bits
#define DIFF_PICKAXE_ALL 1
#define DIFF_PICKAXE_REGEX 2
#define DIFF_PICKAXE_KIND_S 4
#define DIFF_PICKAXE_KIND_G 8
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach diff a new algorithm, one that attempts to prevent user-specified
lines from appearing as a deletion or addition in the end result. The
end user can use this by specifying "--anchored=<text>" one or more
times when using Git commands like "diff" and "show".
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A single-word "unsigned flags" in the diff options is being split
into a structure with many bitfields.
* bw/diff-opt-impl-to-bitfields:
diff: make struct diff_flags members lowercase
diff: remove DIFF_OPT_CLR macro
diff: remove DIFF_OPT_SET macro
diff: remove DIFF_OPT_TST macro
diff: remove touched flags
diff: add flag to indicate textconv was set via cmdline
diff: convert flags to be stored in bitfields
add, reset: use DIFF_OPT_SET macro to set a diff flag
Pathspec-limited revision traversal was taught not to keep finding
unneeded differences once it knows two trees are different inside
given pathspec.
* jk/revision-pruning-optim:
revision: quit pruning diff more quickly when possible
Remove the `DIFF_OPT_CLR` macro and instead set the flags directly.
This conversion is done using the following semantic patch:
@@
expression E;
identifier fld;
@@
- DIFF_OPT_CLR(&E, fld)
+ E.flags.fld = 0
@@
type T;
T *ptr;
identifier fld;
@@
- DIFF_OPT_CLR(ptr, fld)
+ ptr->flags.fld = 0
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the `DIFF_OPT_SET` macro and instead set the flags directly.
This conversion is done using the following semantic patch:
@@
expression E;
identifier fld;
@@
- DIFF_OPT_SET(&E, fld)
+ E.flags.fld = 1
@@
type T;
T *ptr;
identifier fld;
@@
- DIFF_OPT_SET(ptr, fld)
+ ptr->flags.fld = 1
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the `DIFF_OPT_TST` macro and instead access the flags directly.
This conversion is done using the following semantic patch:
@@
expression E;
identifier fld;
@@
- DIFF_OPT_TST(&E, fld)
+ E.flags.fld
@@
type T;
T *ptr;
identifier fld;
@@
- DIFF_OPT_TST(ptr, fld)
+ ptr->flags.fld
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the set of parallel touched flags are no longer being used,
remove them.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-show is unique in that it wants to use textconv by default except
for when it is showing blobs. When asked to show a blob, show doesn't
want to use textconv unless the user explicitly requested that it be
used by providing the command line flag '--textconv'.
Currently this is done by using a parallel set of 'touched' flags which
get set every time a particular flag is set or cleared. In a future
patch we want to eliminate this parallel set of flags so instead of
relying on if the textconv flag has been touched, add a new flag
'TEXTCONV_SET_VIA_CMDLINE' which is only set if textconv is set to true
via the command line.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We cannot add many more flags to the diff machinery due to the
limitations of the number of flags that can be stored in a single
unsigned int. In order to allow for more flags to be added to the diff
machinery in the future this patch converts the flags to be stored in
bitfields in 'struct diff_flags'.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the revision traversal machinery is given a pathspec,
we must compute the parent-diff for each commit to determine
which ones are TREESAME. We set the QUICK diff flag to avoid
looking at more entries than we need; we really just care
whether there are any changes at all.
But there is one case where we want to know a bit more: if
--remove-empty is set, we care about finding cases where the
change consists only of added entries (in which case we may
prune the parent in try_to_simplify_commit()). To cover that
case, our file_add_remove() callback does not quit the diff
upon seeing an added entry; it keeps looking for other types
of entries.
But this means when --remove-empty is not set (and it is not
by default), we compute more of the diff than is necessary.
You can see this in a pathological case where a commit adds
a very large number of entries, and we limit based on a
broad pathspec. E.g.:
perl -e '
chomp(my $blob = `git hash-object -w --stdin </dev/null`);
for my $a (1..1000) {
for my $b (1..1000) {
print "100644 $blob\t$a/$b\n";
}
}
' | git update-index --index-info
git commit -qm add
git rev-list HEAD -- .
This case takes about 100ms now, but after this patch only
needs 6ms. That's not a huge improvement, but it's easy to
get and it protects us against even more pathological cases
(e.g., going from 1 million to 10 million files would take
ten times as long with the current code, but not increase at
all after this patch).
This is reported to minorly speed-up pathspec limiting in
real world repositories (like the 100-million-file Windows
repository), but probably won't make a noticeable difference
outside of pathological setups.
This patch actually covers the case without --remove-empty,
and the case where we see only deletions. See the in-code
comment for details.
Note that we have to add a new member to the diff_options
struct so that our callback can see the value of
revs->remove_empty_trees. This callback parameter could be
passed to the "add_remove" and "change" callbacks, but
there's not much point. They already receive the
diff_options struct, and doing it this way avoids having to
update the function signature of the other callbacks
(arguably the format_callback and output_prefix functions
could benefit from the same simplification).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The existing behavior of diff --color-moved=zebra does not define the
minimum size of a block at all, instead relying on a heuristic applied
later to filter out sets of adjacent moved lines that are shorter than 3
lines long. This can be confusing, because a block could thus be colored
as moved at the source but not at the destination (or vice versa),
depending on its neighbors.
Instead, teach diff that the minimum size of a block is 20 alphanumeric
characters, the same heuristic used by "git blame". This allows diff to
still exclude uninteresting lines appearing on their own (such as those
solely consisting of one or a few closing braces), as was the intention
of the adjacent-moved-line heuristic.
This requires a change in some tests in that some of their lines are no
longer considered to be part of a block, because they are too short.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Any lines inside a moved block of code are not interesting. Boundaries
of blocks are only interesting if they are next to another block of moved
code.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the 'plain' mode for move detection of code. This omits the checking
for adjacent blocks, so it is not as useful. If you have a lot of the
same blocks moved in the same patch, the 'Zebra' would end up slow as it
is O(n^2) (n is number of same blocks). So this may be useful there and
is generally easy to add. Instead be very literal at the move detection,
do not skip over short blocks here.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a patch consists mostly of moving blocks of code around, it can
be quite tedious to ensure that the blocks are moved verbatim, and not
undesirably modified in the move. To that end, color blocks that are
moved within the same patch differently. For example (OM, del, add,
and NM are different colors):
[OM] -void sensitive_stuff(void)
[OM] -{
[OM] - if (!is_authorized_user())
[OM] - die("unauthorized");
[OM] - sensitive_stuff(spanning,
[OM] - multiple,
[OM] - lines);
[OM] -}
void another_function()
{
[del] - printf("foo");
[add] + printf("bar");
}
[NM] +void sensitive_stuff(void)
[NM] +{
[NM] + if (!is_authorized_user())
[NM] + die("unauthorized");
[NM] + sensitive_stuff(spanning,
[NM] + multiple,
[NM] + lines);
[NM] +}
However adjacent blocks may be problematic. For example, in this
potentially malicious patch, the swapping of blocks can be spotted:
[OM] -void sensitive_stuff(void)
[OM] -{
[OMA] - if (!is_authorized_user())
[OMA] - die("unauthorized");
[OM] - sensitive_stuff(spanning,
[OM] - multiple,
[OM] - lines);
[OMA] -}
void another_function()
{
[del] - printf("foo");
[add] + printf("bar");
}
[NM] +void sensitive_stuff(void)
[NM] +{
[NMA] + sensitive_stuff(spanning,
[NMA] + multiple,
[NMA] + lines);
[NM] + if (!is_authorized_user())
[NM] + die("unauthorized");
[NMA] +}
If the moved code is larger, it is easier to hide some permutation in the
code, which is why some alternative coloring is needed.
This patch implements the first mode:
* basic alternating 'Zebra' mode
This conveys all information needed to the user. Defer customization to
later patches.
First I implemented an alternative design, which would try to fingerprint
a line by its neighbors to detect if we are in a block or at the boundary.
This idea iss error prone as it inspected each line and its neighboring
lines to determine if the line was (a) moved and (b) if was deep inside
a hunk by having matching neighboring lines. This is unreliable as the
we can construct hunks which have equal neighbors that just exceed the
number of lines inspected. (Think of 'AXYZBXYZCXYZD..' with each letter
as a line, that is permutated to AXYZCXYZBXYZD..').
Instead this provides a dynamic programming greedy algorithm that finds
the largest moved hunk and then has several modes on highlighting bounds.
A note on the options '--submodule=diff' and '--color-words/--word-diff':
In the conversion to use emit_line in the prior patches both submodules
as well as word diff output carefully chose to call emit_line with sign=0.
All output with sign=0 is ignored for move detection purposes in this
patch, such that no weird looking output will be generated for these
cases. This leads to another thought: We could pass on '--color-moved' to
submodules such that they color up moved lines for themselves. If we'd do
so only line moves within a repository boundary are marked up.
It is useful to have moved lines colored, but there are annoying corner
cases, such as a single line moved, that is very common. For example
in a typical patch of C code, we have closing braces that end statement
blocks or functions.
While it is technically true that these lines are moved as they show up
elsewhere, it is harmful for the review as the reviewers attention is
drawn to such a minor side annoyance.
For now let's have a simple solution of hardcoding the number of
moved lines to be at least 3 before coloring them. Note, that the
length is applied across all blocks to find the 'lonely' blocks
that pollute new code, but do not interfere with a permutated
block where each permutation has less lines than 3.
Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce a new option 'emitted_symbols' in the struct diff_options which
controls whether all output is buffered up until all output is available.
It is set internally in diff.c when necessary.
We'll have a new struct 'emitted_string' in diff.c which will be used to
buffer each line. The emitted_string will duplicate the memory of the
line to buffer as that is easiest to reason about for now. In a future
patch we may want to decrease the memory usage by not duplicating all
output for buffering but rather we may want to store offsets into the
file or in case of hunk descriptions such as the similarity score, we
could just store the relevant number and reproduce the text later on.
This approach was chosen as a first step because it is quite simple
compared to the alternative with less memory footprint.
emit_diff_symbol factors out the emission part and depending on the
diff_options->emitted_symbols the emission will be performed directly
when calling emit_diff_symbol or after the whole process is done, i.e.
by buffering we have add the possibility for a second pass over the
whole output before doing the actual output.
In 6440d34 (2012-03-14, diff: tweak a _copy_ of diff_options with
word-diff) we introduced a duplicate diff options struct for word
emissions as we may have different regex settings in there.
When buffering the output, we need to operate on just one buffer,
so we have to copy back the emissions of the word buffer into the
main buffer.
Unconditionally enable output via buffer in this patch as it yields
a great opportunity for testing, i.e. all the diff tests from the
test suite pass without having reordering issues (i.e. only parts
of the output got buffered, and we forgot to buffer other parts).
The test suite passes, which gives confidence that we converted all
functions to use emit_string for output.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We call print_stat_summary from builtin/apply, so we still
need the version with a file pointer, so introduce
print_stat_summary_0 that uses emit_string machinery and
keep print_stat_summary with the same arguments around.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As the submodule process is no longer attached to the same file pointer
'o->file' as the superprojects process, there is a different result in
color.c::check_auto_color. That is why we need to pass coloring explicitly,
such that the submodule coloring decision will be made by the child process
processing the submodule. Only DIFF_SYMBOL_SUBMODULE_PIPETHROUGH contains
color, the other symbols are for embedding the submodule output into the
superprojects output.
Remove the colors from the function signatures, as all the coloring
decisions will be made either inside the child process or the final
emit_diff_symbol, but not in the functions driving the submodule diff.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new flags field to emit_diff_symbol, that will be used by
context lines for:
* white space rules that are applicable (The first 12 bits)
Take a note in cahe.c as well, when this ws rules are extended we have
to fix the bits in the flags field.
* how the rules are evaluated (actually this double encodes the sign
of the line, but the code is easier to keep this way, bits 13,14,15)
* if the line a blank line at EOF (bit 16)
The check if new lines need to be marked up as extra lines at the end of
file, is now done unconditionally. That should be ok, as
'new_blank_line_at_eof' has a quick early return.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The internal logic used in "git blame" has been libified to make it
easier to use by cgit.
* js/blame-lib: (29 commits)
blame: move entry prepend to libgit
blame: move scoreboard setup to libgit
blame: move scoreboard-related methods to libgit
blame: move fake-commit-related methods to libgit
blame: move origin-related methods to libgit
blame: move core structures to header
blame: create entry prepend function
blame: create scoreboard setup function
blame: create scoreboard init function
blame: rework methods that determine 'final' commit
blame: wrap blame_sort and compare_blame_final
blame: move progress updates to a scoreboard callback
blame: make sanity_check use a callback in scoreboard
blame: move no_whole_file_rename flag to scoreboard
blame: move xdl_opts flags to scoreboard
blame: move show_root flag to scoreboard
blame: move reverse flag to scoreboard
blame: move contents_from to scoreboard
blame: move copy/move thresholds to scoreboard
blame: move stat counters to scoreboard
...
Convert diff_change to take a struct object_id. In addition convert the
function pointer type 'change_fn_t' to also take a struct object_id.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert diff_addremove to take a struct object_id. In addtion convert
the function pointer type 'add_remove_fn_t' to also take a struct
object_id.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
textconv_object is used in places other than blame.c and should be moved
to a more appropriate location. Other textconv related functions are
located in diff.c so that seems as good a place as any.
Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is needed to convert parse_tree_indirect.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this structure handles an array of object IDs, rename it to struct
oid_array. Also rename the accessor functions and the initialization
constant.
This commit was produced mechanically by providing non-Documentation
files to the following Perl one-liners:
perl -pi -E 's/struct sha1_array/struct oid_array/g'
perl -pi -E 's/\bsha1_array_/oid_array_/g'
perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g'
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When new paths were added by "git add -N" to the index, it was
enough to circumvent the check by "git commit" to refrain from
making an empty commit without "--allow-empty". The same logic
prevented "git status" to show such a path as "new file" in the
"Changes not staged for commit" section.
* nd/ita-empty-commit:
commit: don't be fooled by ita entries when creating initial commit
commit: fix empty commit creation when there's no changes but ita entries
diff: add --ita-[in]visible-in-index
diff-lib: allow ita entries treated as "not yet exist in index"
Since we're modifying this function anyway, it's a good time
to update it to the more modern "struct oid". We can also
drop some of the magic numbers in favor of GIT_SHA1_HEXSZ,
along with some descriptive comments.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The word "align" describes how the function actually differs
from find_unique_abbrev, and will make it less confusing
when we add more diff-specific abbrevation functions that do
not do this alignment.
Since this is a globally available function, let's also move
its descriptive comment to the header file, where we
typically document function interfaces.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If i-t-a entries are present and there is no change between the index
and HEAD i-t-a entries, index_differs_from() still returns "dirty, new
entries" (aka, the resulting commit is not empty), but cache-tree will
skip i-t-a entries and produce the exact same tree of current
commit.
index_differs_from() is supposed to catch this so we can abort
git-commit (unless --no-empty is specified). Update it to optionally
ignore i-t-a entries when doing a diff between the index and HEAD so
that it would return "no change" in this case and abort commit.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When comparing the index and the working tree to show which paths are
new, and comparing the tree recorded in the HEAD and the index to see if
committing the contents recorded in the index would result in an empty
commit, we would want the former comparison to say "these are new paths"
and the latter to say "there is no change" for paths that are marked as
intent-to-add.
We made a similar attempt at d95d728a ("diff-lib.c: adjust position of
i-t-a entries in diff", 2015-03-16), which redefined the semantics of
these two comparison modes globally, which was a disaster and had to be
reverted at 78cc1a54 ("Revert "diff-lib.c: adjust position of i-t-a
entries in diff"", 2015-06-23).
To make sure we do not repeat the same mistake, introduce a new internal
diffopt option so that this different semantics can be asked for only by
callers that ask it, while making sure other unaudited callers will get
the same comparison result.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Output from "git diff" can be made easier to read by selecting
which lines are common and which lines are added/deleted
intelligently when the lines before and after the changed section
are the same. A command line option is added to help with the
experiment to find a good heuristics.
* mh/diff-indent-heuristic:
blame: honor the diff heuristic options and config
parse-options: add parse_opt_unknown_cb()
diff: improve positioning of add/delete blocks in diffs
xdl_change_compact(): introduce the concept of a change group
recs_match(): take two xrecord_t pointers as arguments
is_blank_line(): take a single xrecord_t as argument
xdl_change_compact(): only use heuristic if group can't be matched
xdl_change_compact(): fix compaction heuristic to adjust ixo
Teach "git blame" and "git annotate" the --compaction-heuristic and
--indent-heuristic options that are now supported by "git diff".
Also teach them to honor the `diff.compactionHeuristic` and
`diff.indentHeuristic` configuration options.
It would be conceivable to introduce separate configuration options for
"blame" and "annotate"; for example `blame.compactionHeuristic` and
`blame.indentHeuristic`. But it would be confusing to users if blame
output is inconsistent with diff output, so it makes more sense for them
to respect the same configuration.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "git diff --submodule={short,log}" mechanism has been enhanced
to allow "--submodule=diff" to show the patch between the submodule
commits bound to the superproject.
* jk/diff-submodule-diff-inline:
diff: teach diff to display submodule difference with an inline diff
submodule: refactor show_submodule_summary with helper function
submodule: convert show_submodule_summary to use struct object_id *
allow do_submodule_path to work even if submodule isn't checked out
diff: prepare for additional submodule formats
graph: add support for --line-prefix on all graph-aware output
diff.c: remove output_prefix_length field
cache: add empty_tree_oid object and helper function
Teach git-diff and friends a new format for displaying the difference
of a submodule. The new format is an inline diff of the contents of the
submodule between the commit range of the update. This allows the user
to see the actual code change caused by a submodule update.
Add tests for the new format and option.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A future patch will add a new format for displaying the difference of
a submodule. Make it easier by changing how we store the current
selected format. Replace the DIFF_OPT flag with an enumeration, as each
format will be mutually exclusive.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add an extension to git-diff and git-log (and any other graph-aware
displayable output) such that "--line-prefix=<string>" will print the
additional line-prefix on every line of output.
To make this work, we have to fix a few bugs in the graph API that force
graph_show_commit_msg to be used only when you have a valid graph.
Additionally, we extend the default_diff_output_prefix handler to work
even when no graph is enabled.
This is somewhat of a hack on top of the graph API, but I think it
should be acceptable here.
This will be used by a future extension of submodule display which
displays the submodule diff as the actual diff between the pre and post
commit in the submodule project.
Add some tests for both git-log and git-diff to ensure that the prefix
is honored correctly.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"diff/log --stat" has a logic that determines the display columns
available for the diffstat part of the output and apportions it for
pathnames and diffstat graph automatically.
5e71a84a (Add output_prefix_length to diff_options, 2012-04-16)
added the output_prefix_length field to diff_options structure to
allow this logic to subtract the display columns used for the
history graph part from the total "terminal width"; this matters
when the "git log --graph -p" option is in use.
The field must be set to the number of display columns needed to
show the output from the output_prefix() callback, which is error
prone. As there is only one user of the field, and the user has the
actual value of the prefix string, let's get rid of the field and
have the user count the display width itself.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This will allow a diff patch id to be created using only the header data
so that the contents of the file will not have to be loaded.
Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The end-user facing Porcelain level commands like "diff" and "log"
now enables the rename detection by default.
* mm/diff-renames-default:
diff: activate diff.renames by default
log: introduce init_log_defaults()
t: add tests for diff.renames (true/false/unset)
t4001-diff-rename: wrap file creations in a test
Documentation/diff-config: fix description of diff.renames
Update various codepaths to avoid manually-counted malloc().
* jk/tighten-alloc: (22 commits)
ewah: convert to REALLOC_ARRAY, etc
convert ewah/bitmap code to use xmalloc
diff_populate_gitlink: use a strbuf
transport_anonymize_url: use xstrfmt
git-compat-util: drop mempcpy compat code
sequencer: simplify memory allocation of get_message
test-path-utils: fix normalize_path_copy output buffer size
fetch-pack: simplify add_sought_entry
fast-import: simplify allocation in start_packfile
write_untracked_extension: use FLEX_ALLOC helper
prepare_{git,shell}_cmd: use argv_array
use st_add and st_mult for allocation size computation
convert trivial cases to FLEX_ARRAY macros
use xmallocz to avoid size arithmetic
convert trivial cases to ALLOC_ARRAY
convert manual allocations to argv_array
argv-array: add detach function
add helpers for allocating flex-array structs
harden REALLOC_ARRAY and xcalloc against size_t overflow
tree-diff: catch integer overflow in combine_diff_path allocation
...
The memory ownership rule of fill_textconv() API, which was a bit
tricky, has been documented a bit better.
* jk/more-comments-on-textconv:
diff: clarify textconv interface
Rename detection is a very convenient feature, and new users shouldn't
have to dig in the documentation to benefit from it.
Potential objections to activating rename detection are that it
sometimes fail, and it is sometimes slow. But rename detection is
already activated by default in several cases like "git status" and "git
merge", so activating diff.renames does not fundamentally change the
situation. When the rename detection fails, it now fails consistently
between "git diff" and "git status".
This setting does not affect plumbing commands, hence well-written
scripts will not be affected.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The memory allocation scheme for the textconv interface is a
bit tricky, and not well documented. It was originally
designed as an internal part of diff.c (matching
fill_mmfile), but gradually was made public.
Refactoring it is difficult, but we can at least improve the
situation by documenting the intended flow and enforcing it
with an in-code assertion.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A combine_diff_path struct has two "flex" members allocated
alongside the struct: a string to hold the pathname, and an
array of parent pointers. We use an "int" to compute this,
meaning we may easily overflow it if the pathname is
extremely long.
We can fix this by using size_t, and checking for overflow
with the st_add helper.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A few options of "git diff" did not work well when the command was
run from a subdirectory.
* nd/diff-with-path-params:
diff: make -O and --output work in subdirectory
diff-no-index: do not take a redundant prefix argument
A few options of "git diff" did not work well when the command was
run from a subdirectory.
* nd/diff-with-path-params:
diff: make -O and --output work in subdirectory
diff-no-index: do not take a redundant prefix argument
Prefix is already set up in "revs". The same prefix should be used for
all options parsing. So kill the last argument. This patch does not
actually change anything because the only caller does use the same
prefix for init_revisions() and diff_no_index().
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We sometimes use 32-bit unsigned integers as bit-fields.
It's fine to access the MSB, because it's unsigned. However,
doing so as "1 << 31" is wrong, because the constant "1" is
a signed int, and we shift into the sign bit, causing
undefined behavior.
We can fix this by using "1U" as the constant.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
People who work on projects with mostly linear history with frequent
whole file renames may want to always use "git log --follow" when
inspecting the life of the content that live in a single path.
Teach the command to behave as if "--follow" was given from the
command line when log.follow configuration variable is set *and*
there is one (and only one) path on the command line.
Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"color.diff.plain" was a misnomer; give it 'color.diff.context' as
a more logical synonym.
* jk/color-diff-plain-is-context:
diff.h: rename DIFF_PLAIN color slot to DIFF_CONTEXT
diff: accept color.diff.context as a synonym for "plain"
Allow whitespace breakages in deleted and context lines to be also
painted in the output.
* jc/diff-ws-error-highlight:
diff.c: --ws-error-highlight=<kind> option
diff.c: add emit_del_line() and emit_context_line()
t4015: separate common setup and per-test expectation
t4015: modernise style
The latter is a much more descriptive name (and we support
"color.diff.context" now). This also updates the name of any
local variables which were used to store the color.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Traditionally, we only cared about whitespace breakages introduced
in new lines. Some people want to paint whitespace breakages on old
lines, too. When they see a whitespace breakage on a new line, they
can spot the same kind of whitespace breakage on the corresponding
old line and want to say "Ah, those breakages are there but they
were inherited from the original, so let's not touch them for now."
Introduce `--ws-error-highlight=<kind>` option, that lets them pass
a comma separated list of `old`, `new`, and `context` to specify
what lines to highlight whitespace errors on.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Also, convert a constant to GIT_SHA1_HEXSZ.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of running N pair-wise diff-trees when inspecting a
N-parent merge, find the set of paths that were touched by walking
N+1 trees in parallel. These set of paths can then be turned into
N pair-wise diff-tree results to be processed through rename
detections and such. And N=2 case nicely degenerates to the usual
2-way diff-tree, which is very nice.
* ks/tree-diff-nway:
mingw: activate alloca
combine-diff: speed it up, by using multiparent diff tree-walker directly
tree-diff: rework diff_tree() to generate diffs for multiparent cases as well
Portable alloca for Git
tree-diff: reuse base str(buf) memory on sub-tree recursion
tree-diff: no need to call "full" diff_tree_sha1 from show_path()
tree-diff: rework diff_tree interface to be sha1 based
tree-diff: diff_tree() should now be static
tree-diff: remove special-case diff-emitting code for empty-tree cases
tree-diff: simplify tree_entry_pathcmp
tree-diff: show_path prototype is not needed anymore
tree-diff: rename compare_tree_entry -> tree_entry_pathcmp
tree-diff: move all action-taking code out of compare_tree_entry()
tree-diff: don't assume compare_tree_entry() returns -1,0,1
tree-diff: consolidate code for emitting diffs and recursion in one place
tree-diff: show_tree() is not needed
tree-diff: no need to pass match to skip_uninteresting()
tree-diff: no need to manually verify that there is no mode change for a path
combine-diff: move changed-paths scanning logic into its own function
combine-diff: move show_log_first logic/action out of paths scanning
Previously diff_tree(), which is now named ll_diff_tree_sha1(), was
generating diff_filepair(s) for two trees t1 and t2, and that was
usually used for a commit as t1=HEAD~, and t2=HEAD - i.e. to see changes
a commit introduces.
In Git, however, we have fundamentally built flexibility in that a
commit can have many parents - 1 for a plain commit, 2 for a simple merge,
but also more than 2 for merging several heads at once.
For merges there is a so called combine-diff, which shows diff, a merge
introduces by itself, omitting changes done by any parent. That works
through first finding paths, that are different to all parents, and then
showing generalized diff, with separate columns for +/- for each parent.
The code lives in combine-diff.c .
There is an impedance mismatch, however, in that a commit could
generally have any number of parents, and that while diffing trees, we
divide cases for 2-tree diffs and more-than-2-tree diffs. I mean there
is no special casing for multiple parents commits in e.g.
revision-walker .
That impedance mismatch *hurts* *performance* *badly* for generating
combined diffs - in "combine-diff: optimize combine_diff_path
sets intersection" I've already removed some slowness from it, but from
the timings provided there, it could be seen, that combined diffs still
cost more than an order of magnitude more cpu time, compared to diff for
usual commits, and that would only be an optimistic estimate, if we take
into account that for e.g. linux.git there is only one merge for several
dozens of plain commits.
That slowness comes from the fact that currently, while generating
combined diff, a lot of time is spent computing diff(commit,commit^2)
just to only then intersect that huge diff to almost small set of files
from diff(commit,commit^1).
That's because at present, to compute combine-diff, for first finding
paths, that "every parent touches", we use the following combine-diff
property/definition:
D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn) (w.r.t. paths)
where
D(A,P1...Pn) is combined diff between commit A, and parents Pi
and
D(A,Pi) is usual two-tree diff Pi..A
So if any of that D(A,Pi) is huge, tracting 1 n-parent combine-diff as n
1-parent diffs and intersecting results will be slow.
And usually, for linux.git and other topic-based workflows, that
D(A,P2) is huge, because, if merge-base of A and P2, is several dozens
of merges (from A, via first parent) below, that D(A,P2) will be diffing
sum of merges from several subsystems to 1 subsystem.
The solution is to avoid computing n 1-parent diffs, and to find
changed-to-all-parents paths via scanning A's and all Pi's trees
simultaneously, at each step comparing their entries, and based on that
comparison, populate paths result, and deduce we could *skip*
*recursing* into subdirectories, if at least for 1 parent, sha1 of that
dir tree is the same as in A. That would save us from doing significant
amount of needless work.
Such approach is very similar to what diff_tree() does, only there we
deal with scanning only 2 trees simultaneously, and for n+1 tree, the
logic is a bit more complex:
D(T,P1...Pn) calculation scheme
-------------------------------
D(T,P1...Pn) = D(T,P1) ^ ... ^ D(T,Pn) (regarding resulting paths set)
D(T,Pj) - diff between T..Pj
D(T,P1...Pn) - combined diff from T to parents P1,...,Pn
We start from all trees, which are sorted, and compare their entries in
lock-step:
T P1 Pn
- - -
|t| |p1| |pn|
|-| |--| ... |--| imin = argmin(p1...pn)
| | | | | |
|-| |--| |--|
|.| |. | |. |
. . .
. . .
at any time there could be 3 cases:
1) t < p[imin];
2) t > p[imin];
3) t = p[imin].
Schematic deduction of what every case means, and what to do, follows:
1) t < p[imin] -> ∀j t ∉ Pj -> "+t" ∈ D(T,Pj) -> D += "+t"; t↓
2) t > p[imin]
2.1) ∃j: pj > p[imin] -> "-p[imin]" ∉ D(T,Pj) -> D += ø; ∀ pi=p[imin] pi↓
2.2) ∀i pi = p[imin] -> pi ∉ T -> "-pi" ∈ D(T,Pi) -> D += "-p[imin]"; ∀i pi↓
3) t = p[imin]
3.1) ∃j: pj > p[imin] -> "+t" ∈ D(T,Pj) -> only pi=p[imin] remains to investigate
3.2) pi = p[imin] -> investigate δ(t,pi)
|
|
v
3.1+3.2) looking at δ(t,pi) ∀i: pi=p[imin] - if all != ø ->
⎧δ(t,pi) - if pi=p[imin]
-> D += ⎨
⎩"+t" - if pi>p[imin]
in any case t↓ ∀ pi=p[imin] pi↓
~
For comparison, here is how diff_tree() works:
D(A,B) calculation scheme
-------------------------
A B
- -
|a| |b| a < b -> a ∉ B -> D(A,B) += +a a↓
|-| |-| a > b -> b ∉ A -> D(A,B) += -b b↓
| | | | a = b -> investigate δ(a,b) a↓ b↓
|-| |-|
|.| |.|
. .
. .
~~~~~~~~
This patch generalizes diff tree-walker to work with arbitrary number of
parents as described above - i.e. now there is a resulting tree t, and
some parents trees tp[i] i=[0..nparent). The generalization builds on
the fact that usual diff
D(A,B)
is by definition the same as combined diff
D(A,[B]),
so if we could rework the code for common case and make it be not slower
for nparent=1 case, usual diff(t1,t2) generation will not be slower, and
multiparent diff tree-walker would greatly benefit generating
combine-diff.
What we do is as follows:
1) diff tree-walker ll_diff_tree_sha1() is internally reworked to be
a paths generator (new name diff_tree_paths()), with each generated path
being `struct combine_diff_path` with info for path, new sha1,mode and for
every parent which sha1,mode it was in it.
2) From that info, we can still generate usual diff queue with
struct diff_filepairs, via "exporting" generated
combine_diff_path, if we know we run for nparent=1 case.
(see emit_diff() which is now named emit_diff_first_parent_only())
3) In order for diff_can_quit_early(), which checks
DIFF_OPT_TST(opt, HAS_CHANGES))
to work, that exporting have to be happening not in bulk, but
incrementally, one diff path at a time.
For such consumers, there is a new callback in diff_options
introduced:
->pathchange(opt, struct combine_diff_path *)
which, if set to !NULL, is called for every generated path.
(see new compat ll_diff_tree_sha1() wrapper around new paths
generator for setup)
4) The paths generation itself, is reworked from previous
ll_diff_tree_sha1() code according to "D(A,P1...Pn) calculation
scheme" provided above:
On the start we allocate [nparent] arrays in place what was
earlier just for one parent tree.
then we just generalize loops, and comparison according to the
algorithm.
Some notes(*):
1) alloca(), for small arrays, is used for "runs not slower for
nparent=1 case than before" goal - if we change it to xmalloc()/free()
the timings get ~1% worse. For alloca() we use just-introduced
xalloca/xalloca_free compatibility wrappers, so it should not be a
portability problem.
2) For every parent tree, we need to keep a tag, whether entry from that
parent equals to entry from minimal parent. For performance reasons I'm
keeping that tag in entry's mode field in unused bit - see S_IFXMIN_NEQ.
Not doing so, we'd need to alloca another [nparent] array, which hurts
performance.
3) For emitted paths, memory could be reused, if we know the path was
processed via callback and will not be needed later. We use efficient
hand-made realloc-style path_appendnew(), that saves us from ~1-1.5%
of potential additional slowdown.
4) goto(s) are used in several places, as the code executes a little bit
faster with lowered register pressure.
Also
- we should now check for FIND_COPIES_HARDER not only when two entries
names are the same, and their hashes are equal, but also for a case,
when a path was removed from some of all parents having it.
The reason is, if we don't, that path won't be emitted at all (see
"a > xi" case), and we'll just skip it, and FIND_COPIES_HARDER wants
all paths - with diff or without - to be emitted, to be later analyzed
for being copies sources.
The new check is only necessary for nparent >1, as for nparent=1 case
xmin_eqtotal always =1 =nparent, and a path is always added to diff as
removal.
~~~~~~~~
Timings for
# without -c, i.e. testing only nparent=1 case
`git log --raw --no-abbrev --no-renames`
before and after the patch are as follows:
navy.git linux.git v3.10..v3.11
before 0.611s 1.889s
after 0.619s 1.907s
slowdown 1.3% 0.9%
This timings show we did no harm to usual diff(tree1,tree2) generation.
From the table we can see that we actually did ~1% slowdown, but I think
I've "earned" that 1% in the previous patch ("tree-diff: reuse base
str(buf) memory on sub-tree recursion", HEAD~~) so for nparent=1 case,
net timings stays approximately the same.
The output also stayed the same.
(*) If we revert 1)-4) to more usual techniques, for nparent=1 case,
we'll get ~2-2.5% of additional slowdown, which I've tried to avoid, as
"do no harm for nparent=1 case" rule.
For linux.git, combined diff will run an order of magnitude faster and
appropriate timings will be provided in the next commit, as we'll be
taking advantage of the new diff tree-walker for combined-diff
generation there.
P.S. and combined diff is not some exotic/for-play-only stuff - for
example for a program I write to represent Git archives as readonly
filesystem, there is initial scan with
`git log --reverse --raw --no-abbrev --no-renames -c`
to extract log of what was created/changed when, as a result building a
map
{} sha1 -> in which commit (and date) a content was added
that `-c` means also show combined diff for merges, and without them, if
a merge is non-trivial (merges changes from two parents with both having
separate changes to a file), or an evil one, the map will not be full,
i.e. some valid sha1 would be absent from it.
That case was my initial motivation for combined diffs speedup.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We reworked all its users to use the functionality through
diff_tree_sha1 variant in recent patches (see "tree-diff: allow
diff_tree_sha1 to accept NULL sha1" and what comes next).
diff_tree() is now not used outside tree-diff.c - make it static.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The field was used in order to speed-up name comparison and also to
mark removed paths by setting it to 0.
Because the updated code does significantly less strcmp and also
just removes paths from the list and free right after we know a path
will not be needed, it is not needed anymore.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff ../else/where/A ../else/where/B" when ../else/where is
clearly outside the repository, and "git diff --no-index A B", do
not have to look at the index at all, but we used to read the index
unconditionally.
* tg/diff-no-index-refactor:
diff: avoid some nesting
diff: add test for --no-index executed outside repo
diff: don't read index when --no-index is given
diff: move no-index detection to builtin/diff.c
Show the total number of paths and the number of paths shown so far
when "git difftool" prompts to launch an external diff tool, which
would give users some sense of progress.
* zk/difftool-counts:
diff.c: fix some recent whitespace style violations
difftool: display the number of files in the diff queue in the prompt
Currently the --no-index option is parsed in diff_no_index(). Move the
detection if a no-index diff should be executed to builtin/diff.c, where
we can use it for executing diff_no_index() conditionally. This will
also allow us to execute other operations conditionally, which will be
done in the next patch.
There are no functional changes.
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
