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29 commits

Author SHA1 Message Date
Sergey Organov
5acffd3473 diff-index: restore -c/--cc options handling
This fixes 19b2517f (diff-merges: move specific diff-index "-m"
handling to diff-index, 2021-05-21).

That commit disabled handling of all diff for merges options in
diff-index on an assumption that they are unused. However, it later
appeared that -c and --cc, even though undocumented and not being
covered by tests, happen to have had particular effect on diff-index
output.

Restore original -c/--cc options handling by diff-index.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07 11:11:35 -07:00
Jonathan Nieder
6a38e33331 Revert 'diff-merges: let "-m" imply "-p"'
This reverts commit f5bfcc823b, which
made "git log -m" imply "--patch" by default.  The logic was that
"-m", which makes diff generation for merges perform a diff against
each parent, has no use unless I am viewing the diff, so we could save
the user some typing by turning on display of the resulting diff
automatically.  That wasn't expected to adversely affect scripts
because scripts would either be using a command like "git diff-tree"
that already emits diffs by default or would be combining -m with a
diff generation option such as --name-status.  By saving typing for
interactive use without adversely affecting scripts in the wild, it
would be a pure improvement.

The problem is that although diff generation options are only relevant
for the displayed diff, a script author can imagine them affecting
path limiting.  For example, I might run

	git log -w --format=%H -- README

hoping to list commits that edited README, excluding whitespace-only
changes.  In fact, a whitespace-only change is not TREESAME so the use
of -w here has no effect (since we don't apply these diff generation
flags to the diff_options struct rev_info::pruning used for this
purpose), but the documentation suggests that it should work

	Suppose you specified foo as the <paths>. We shall call
	commits that modify foo !TREESAME, and the rest TREESAME. (In
	a diff filtered for foo, they look different and equal,
	respectively.)

and a script author who has not tested whitespace-only changes
wouldn't notice.

Similarly, a script author could include

	git log -m --first-parent --format=%H -- README

to filter the first-parent history for commits that modified README.
The -m is a no-op but it reflects the script author's intent.  For
example, until 1e20a407fe (stash list: stop passing "-m" to "git
log", 2021-05-21), "git stash list" did this.

As a result, we can't safely change "-m" to imply "-p" without fear of
breaking such scripts.  Restore the previous behavior.

Noticed because Rust's src/bootstrap/bootstrap.py made use of this
same construct: https://github.com/rust-lang/rust/pull/87513.  That
script has been updated to omit the unnecessary "-m" option, but we
can expect other scripts in the wild to have similar expectations.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-09 13:52:01 -07:00
Sergey Organov
f5bfcc823b diff-merges: let "-m" imply "-p"
Fix long standing inconsistency between -c/--cc that do imply -p on
one side, and -m that did not imply -p on the other side.

Change corresponding test accordingly, as "log -m" output should now
match one from "log -m -p", rather than from just "log".

Change documentation accordingly.

NOTES:

After this patch

  git log -m

produces diffs without need to provide -p as well, that improves both
consistency and usability. It gets even more useful if one sets
"log.diffMerges" configuration variable to "first-parent" to force -m
produce usual diff with respect to first parent only.

This patch, however, does not change behavior when specific diff
format is explicitly provided on the command-line, so that commands
like

  git log -m --raw
  git log -m --stat

are not affected, nor does it change commands where specific diff
format is active by default, such as:

  git diff-tree -m

It's also worth to be noticed that exact historical semantics of -m is
still provided by --diff-merges=separate.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-21 09:24:14 +09:00
Sergey Organov
fd16a39944 diff-merges: rename "combined_imply_patch" to "merges_imply_patch"
This is refactoring change in preparation for the next commit that
will let -m imply -p.

The old name doesn't match the intention to let not only -c/-cc imply
-p, but also -m, that is not a "combined" format, so we rename the
flag accordingly.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-21 09:24:14 +09:00
Sergey Organov
19b2517f95 diff-merges: move specific diff-index "-m" handling to diff-index
Move specific handling of "-m" for diff-index to diff-index.c, so
diff-merges is left to handle only diff for merges options.

Being a better design by itself, this is especially essential in
preparation for letting -m imply -p, as "diff-index -m" obviously
should not imply -p, as it's entirely unrelated.

To handle this, in addition to moving specific diff-index "-m" code
out of diff-merges, we introduce new

  diff_merges_suppress_options_parsing()

and call it before generic options processing in cmd_diff_index().

This new diff_merges_suppress_options_parsing() could then be reused
and called before invocations of setup_revisions() for other commands
that don't need --diff-merges options, but that's outside of the scope
of these patch series.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-21 09:24:14 +09:00
Sergey Organov
17c13e60fd diff-merges: introduce log.diffMerges config variable
New log.diffMerges configuration variable sets the format that
--diff-merges=on will be using. The default is "separate".

t4013: add the following tests for log.diffMerges config:

* Test that wrong values are denied.

* Test that the value of log.diffMerges properly affects both
--diff-merges=on and -m.

t9902: fix completion tests for log.d* to match log.diffMerges.

Added documentation for log.diffMerges.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-16 23:38:35 -07:00
Sergey Organov
38fc4dbbc2 diff-merges: adapt -m to enable default diff format
Let -m option (and --diff-merges=m) enable the default format instead
of "separate", to be able to tune it with log.diffMerges option.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-16 23:38:35 -07:00
Sergey Organov
26a0f58da8 diff-merges: refactor set_diff_merges()
Split set_diff_merges() into separate parsing and execution functions,
the former to be reused for parsing of configuration values later in
the patch series.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-16 23:38:35 -07:00
Sergey Organov
4320815eb9 diff-merges: introduce --diff-merges=on
Introduce the notion of default diff format for merges, and the option
"on" to select it. The default format is "separate" and can't yet
be changed, so effectively "on" is just a synonym for "separate"
for now. Add corresponding test to t4013.

This is in preparation for introducing log.diffMerges configuration
option that will let --diff-merges=on to be configured to any
supported format.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-16 23:38:35 -07:00
Sergey Organov
388091fe4d diff-merges: add '--diff-merges=1' as synonym for 'first-parent'
As we now have --diff-merges={m|c|cc}, add --diff-merges=1 as synonym
for --diff-merges=first-parent, to have shorter mnemonics for it as
well.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:32 -08:00
Sergey Organov
5071c75316 diff-merges: add old mnemonic counterparts to --diff-merges
This adds --diff-merges={m|c|cc} values that match mnemonics of old
options, for those who are used to them.

Note that, say, --diff-meres=cc behaves differently than --cc, as the
latter implies -p and therefore enables diffs for all the commits,
while the former enables output of diffs for merge commits only.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:32 -08:00
Sergey Organov
a6d19ecc6b diff-merges: let new options enable diff without -p
New options don't have any visible effect unless -p is either given or
implied, as unlike -c/-cc we don't imply -p with --diff-merges. To fix
this, this patch adds new functionality by letting new options enable
output of diffs for merge commits only.

Add 'merges_need_diff' field and set it whenever diff output for merges is
enabled by any of the new options.

Extend diff output logic accordingly, to output diffs for merges when
'merges_need_diff' is set even when no -p has been provided.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:32 -08:00
Sergey Organov
5733b20f41 diff-merges: do not imply -p for new options
Add 'combined_imply_patch' field and set it only for old --cc/-c
options, then imply -p if this flag is set instead of implying -p
whenever 'combined_merge' flag is set.

We don't want new --diff-merge options to imply -p, to make it
possible to enable output of diffs for merges independently from
non-merge commits. At the same time we want to preserve behavior of
old --c/-c/-m options and their interactions with --first-parent, to
stay backward-compatible.

This patch is first step in this direction: it separates old "--cc/-c
imply -p" logic from the rest of the options.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:32 -08:00
Sergey Organov
8c0ba528bc diff-merges: implement new values for --diff-merges
We first implement new options as exact synonyms for their original
counterparts, to get all the infrastructure right, and keep functional
improvements for later commits.

The following values are implemented:

--diff-merges=	        old equivalent
first|first-parent    = --first-parent (only format implications)
sep|separate          = -m
comb|combined         = -c
dense| dense-combined = --cc

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:32 -08:00
Sergey Organov
255a4dacc5 diff-merges: make -m/-c/--cc explicitly mutually exclusive
-c/--cc got precedence over -m only because of external logic where
corresponding flags are checked before that for -m. This is too
error-prone, so add code that explicitly makes these 3 options
mutually exclusive, so that the last option specified on the
command-line gets precedence.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
3d2b5f2f49 diff-merges: refactor opt settings into separate functions
To prepare introduction of new options some of which will be synonyms
to existing options, let every option handling code just call
corresponding function.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
a6e66af923 diff-merges: get rid of now empty diff_merges_init_revs()
After getting rid of 'ignore_merges' field, the diff_merges_init_revs()
function became empty. Get rid of it.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
1a2c4d8050 diff-merges: split 'ignore_merges' field
'ignore_merges' was 3-way field that served two distinct purposes that
we now assign to 2 new independent flags: 'separate_merges', and
'explicit_diff_merges'.

'separate_merges' tells that we need to output diff format containing
separate diff for every parent (as opposed to 'combine_merges').

'explicit_diff_merges' tells that at least one of diff-merges options
has been explicitly specified on the command line, so no defaults
should apply.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
6fc944d895 diff-merges: fix -m to properly override -c/--cc
Logically, -m, -c, --cc specify 3 different formats for representing
merge commits, yet -m doesn't in fact override -c or --cc, that makes
no sense.

Fix -m to properly override -c/--cc, and change the tests accordingly.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
e121b4b822 diff-merges: revise revs->diff flag handling
Do not set revs->diff when we encounter an option that needs it, as
it'd be impossible to undo later. Besides, some other options than
what we handle here set this flag as well, and we'd interfere with
them trying to clear this flag later.

Rather set revs->diff, if finally needed, in diff_merges_setup_revs().

As an additional bonus, this also makes our code shorter.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
0c627f5d3c diff-merges: handle imply -p on -c/--cc logic for log.c
Move logic that handles implying -p on -c/--cc from
log_setup_revisions_tweak() to diff_merges_setup_revs(), where it
belongs.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
3291eea310 diff-merges: introduce revs->first_parent_merges flag
This new field allows us to separate format of diff for merges from
'first_parent_only' flag which primary purpose is limiting history
traversal.

This change further localizes diff format selection logic into the
diff-merges.c file.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
3b6c17b5c0 diff-merges: new function diff_merges_set_dense_combined_if_unset()
Call it where given functionality is needed instead of direct
checking/tweaking of diff merges related fields.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
09322b1da9 diff-merges: new function diff_merges_suppress()
This function sets all the relevant flags to disabled state, so that
no code that checks only one of them get it wrong.

Then we call this new function everywhere where diff merges output
suppression is needed.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
564a4fc847 diff-merges: re-arrange functions to match the order they are called in
For clarity, define public functions in the order they are called, to
make logic inter-dependencies easier to grok.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
4f54544d73 diff-merges: rename diff_merges_default_to_enable() to match semantics
Rename diff_merges_default_to_enable() to
diff_merges_default_to_first_parent() to match its semantics.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Sergey Organov
7acf0d06f5 diff-merges: move checks for first_parent_only out of the module
The checks for first_parent_only don't in fact belong to this module,
as the primary purpose of this flag is history traversal limiting, so
get it out of this module and rename the

diff_merges_first_parent_defaults_to_enable()

to

diff_merges_default_to_enable()

to match new semantics.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:30 -08:00
Sergey Organov
18f09473bf diff-merges: rename all functions to have common prefix
Use the same "diff_merges" prefix for all the diff merges function
names.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:30 -08:00
Sergey Organov
a37eec6333 revision: move diff merges functions to its own diff-merges.c
Create separate diff-merges.c and diff-merges.h files, and move all
the code related to handling of diff merges there.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:30 -08:00