In `resolve_gitlink_ref()` we implicitly rely on `the_repository` to
look up the submodule ref store. Now that we can look up submodule ref
stores for arbitrary repositories we can improve this function to
instead accept a repository as parameter for which we want to resolve
the gitlink.
Do so and adjust callers accordingly.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
d44e5267ea (diff-lib: plug minor memory leaks in do_diff_cache(),
2020-11-14) added the call to diff_setup_done() to release the memory
of the parseopt member of struct diff_options that repo_init_revisions()
had allocated via repo_diff_setup() and prep_parse_options().
189e97bc4b (diff: remove parseopts member from struct diff_options,
2022-12-01) did away with that allocation; diff_setup_done() doesn't
release any memory anymore. So stop calling this function on the blank
diffopt member before it is overwritten, as this is no longer necessary.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unlike "git add" and other end-user facing commands, where it is
diagnosed as an error to give a pathspec with an element that does
not match any path, the diff machinery does not care if some
elements of the pathspec do not match. Given that the diff
machinery is heavily used in pathspec-limited "git log" machinery,
and it is common for a path to come and go while traversing the
project history, this is usually a good thing.
However, in some cases we would want to know if all the pathspec
elements matched. For example, "git add -u <pathspec>" internally
uses the machinery used by "git diff-files" to decide contents from
what paths to add to the index, and as an end-user facing command,
"git add -u" would want to report an unmatched pathspec element.
Add a new .ps_matched member next to the .prune_data member in
"struct rev_info" so that we can optionally keep track of the use of
.prune_data pathspec elements that can be inspected by the caller.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Work to support a repository that work with both SHA-1 and SHA-256
hash algorithms has started.
* eb/hash-transition: (30 commits)
t1016-compatObjectFormat: add tests to verify the conversion between objects
t1006: test oid compatibility with cat-file
t1006: rename sha1 to oid
test-lib: compute the compatibility hash so tests may use it
builtin/ls-tree: let the oid determine the output algorithm
object-file: handle compat objects in check_object_signature
tree-walk: init_tree_desc take an oid to get the hash algorithm
builtin/cat-file: let the oid determine the output algorithm
rev-parse: add an --output-object-format parameter
repository: implement extensions.compatObjectFormat
object-file: update object_info_extended to reencode objects
object-file-convert: convert commits that embed signed tags
object-file-convert: convert commit objects when writing
object-file-convert: don't leak when converting tag objects
object-file-convert: convert tag objects when writing
object-file-convert: add a function to convert trees between algorithms
object: factor out parse_mode out of fast-import and tree-walk into in object.h
cache: add a function to read an OID of a specific algorithm
tag: sign both hashes
commit: export add_header_signature to support handling signatures on tags
...
The `merge_bases_many()` function was just taught to indicate parsing
errors, and now the `repo_get_merge_bases()` function (which is also
surfaced via the `repo_get_merge_bases()` macro) is aware of that, too.
Naturally, there are a lot of callers that need to be adjusted now, too.
Next step: adjust the callers of `get_octopus_merge_bases()`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove unused header "#include".
* en/header-cleanup:
treewide: remove unnecessary includes in source files
treewide: add direct includes currently only pulled in transitively
trace2/tr2_tls.h: remove unnecessary include
submodule-config.h: remove unnecessary include
pkt-line.h: remove unnecessary include
line-log.h: remove unnecessary include
http.h: remove unnecessary include
fsmonitor--daemon.h: remove unnecessary includes
blame.h: remove unnecessary includes
archive.h: remove unnecessary include
treewide: remove unnecessary includes in source files
treewide: remove unnecessary includes from header files
The optimization based on fsmonitor in the "diff --cached"
codepath is resurrected with the "fake-lstat" introduced earlier.
* jc/diff-cached-fsmonitor-fix:
diff-lib: fix check_removed() when fsmonitor is active
Each of these were checked with
gcc -E -I. ${SOURCE_FILE} | grep ${HEADER_FILE}
to ensure that removing the direct inclusion of the header actually
resulted in that header no longer being included at all (i.e. that
no other header pulled it in transitively).
...except for a few cases where we verified that although the header
was brought in transitively, nothing from it was directly used in
that source file. These cases were:
* builtin/credential-cache.c
* builtin/pull.c
* builtin/send-pack.c
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff --merge-base X other args..." insisted that X must be a
commit and errored out when given an annotated tag that peels to a
commit, but we only need it to be a committish. This has been
corrected.
* ar/diff-index-merge-base-fix:
diff: fix --merge-base with annotated tags
To make it possible for git ls-tree to display the tree encoded
in the hash algorithm of the oid specified to git ls-tree, update
init_tree_desc to take as a parameter the oid of the tree object.
Update all callers of init_tree_desc and init_tree_desc_gently
to pass the oid of the tree object.
Use the oid of the tree object to discover the hash algorithm
of the oid and store that hash algorithm in struct tree_desc.
Use the hash algorithm in decode_tree_entry and
update_tree_entry_internal to handle reading a tree object encoded in
a hash algorithm that differs from the repositories hash algorithm.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Checking early for OBJ_COMMIT excludes other objects that can be
resolved to commits, like annotated tags. If we remove it, annotated
tags will be resolved and handled just fine by
lookup_commit_reference(), and if we are given something that can't be
resolved to a commit, we'll still get a useful error message, e.g.:
> error: object 21ab162211ac3ef13c37603ca88b27e9c7e0d40b is a tree, not a commit
> fatal: no merge base found
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff --cached" codepath did not fill the necessary stat
information for a file when fsmonitor knows it is clean and ended
up behaving as if it is not clean, which has been corrected.
* js/diff-cached-fsmonitor-fix:
diff-lib: fix check_removed when fsmonitor is on
`git diff-index` may return incorrect deleted entries when fsmonitor
is used in a repository with git submodules. This can be observed on
Mac machines, but it can affect all other supported platforms too.
If fsmonitor is used, `stat *st` is left uninitialied if cache_entry
has CE_FSMONITOR_VALID bit set. But, there are three call sites
that rely on stat afterwards, which can result in incorrect results.
We can fill members of "struct stat" that matters well enough using
the information we have in "struct cache_entry" that fsmonitor told
us is up-to-date to solve this.
Helped-by: Josip Sokcevic <sokcevic@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git diff-index` may return incorrect deleted entries when fsmonitor
is used in a repository with git submodules. This can be observed on
Mac machines, but it can affect all other supported platforms too.
If fsmonitor is used, `stat *st` is not initialized if cache_entry has
CE_FSMONITOR_VALID set. But, there are three call sites that rely on stat
afterwards, which can result in incorrect results.
This change partially reverts commit 4f3d6d02 (fsmonitor: skip lstat
deletion check during git diff-index, 2021-03-17).
Signed-off-by: Josip Sokcevic <sokcevic@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Neither of these functions ever returns a value other than zero.
Instead, they expect unrecoverable errors to exit immediately, and
things like "--exit-code" are stored inside the diff_options struct to
be handled later via diff_result_code().
Some callers do check the return values, but many don't bother. Let's
drop the useless return values, which are misleading callers about how
the functions work. This could be seen as a step in the wrong direction,
as we might want to eventually "lib-ify" these to more cleanly return
errors up the stack, in which case we'd have to add the return values
back in. But there are some benefits to doing this now:
1. In the current code, somebody could accidentally add a "return -1"
to one of the functions, which would be erroneously ignored by many
callers. By removing the return code, the compiler can notice the
mismatch and force the developer to decide what to do.
Obviously the other option here is that we could start consistently
checking the error code in every caller. But it would be dead code,
and we wouldn't get any compile-time help in catching new cases.
2. It communicates the situation to callers, who may want to choose a
different function. These functions are really thin wrappers for
doing git-diff-files and git-diff-index within the process. But
callers who care about recovering from an error here are probably
better off using the underlying library functions, many of
which do return errors.
If somebody eventually wants to teach these functions to propagate
errors, they'll have to switch back to returning a value, effectively
reverting this patch. But at least then they will be starting with a
level playing field: they know that they will need to inspect each
caller to see how it should handle the error.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Many callers of run_diff_index() passed literal "1" for the option
flag word, which should better be spelled out as DIFF_INDEX_CACHED
for readablity. Everybody else passes "0" that can stay as-is.
The other bit in the option flag word is DIFF_INDEX_MERGE_BASE, but
curiously there is only one caller that can pass it, which is "git
diff-index --merge-base" itself---no internal callers uses the
feature.
A bit tricky call to the function is in builtin/submodule--helper.c
where the .cached member in a private struct is set/reset as a plain
Boolean flag, which happens to be "1" and happens to match the value
of DIFF_INDEX_CACHED.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Header files cleanup.
* en/header-split-cache-h-part-3: (28 commits)
fsmonitor-ll.h: split this header out of fsmonitor.h
hash-ll, hashmap: move oidhash() to hash-ll
object-store-ll.h: split this header out of object-store.h
khash: name the structs that khash declares
merge-ll: rename from ll-merge
git-compat-util.h: remove unneccessary include of wildmatch.h
builtin.h: remove unneccessary includes
list-objects-filter-options.h: remove unneccessary include
diff.h: remove unnecessary include of oidset.h
repository: remove unnecessary include of path.h
log-tree: replace include of revision.h with simple forward declaration
cache.h: remove this no-longer-used header
read-cache*.h: move declarations for read-cache.c functions from cache.h
repository.h: move declaration of the_index from cache.h
merge.h: move declarations for merge.c from cache.h
diff.h: move declaration for global in diff.c from cache.h
preload-index.h: move declarations for preload-index.c from elsewhere
sparse-index.h: move declarations for sparse-index.c from cache.h
name-hash.h: move declarations for name-hash.c from cache.h
run-command.h: move declarations for run-command.c from cache.h
...
This also made it clear that several .c files depended upon various
things that oidset included, but had omitted the direct #include for
those headers. Add those now.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this header showed up in some places besides just #include
statements, update/clean-up/remove those other places as well.
Note that compat/fsmonitor/fsm-path-utils-darwin.c previously got
away with violating the rule that all files must start with an include
of git-compat-util.h (or a short-list of alternate headers that happen
to include it first). This change exposed the violation and caused it
to stop building correctly; fix it by having it include
git-compat-util.h first, as per policy.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For the functions defined in read-cache.c, move their declarations from
cache.h to a new header, read-cache-ll.h. Also move some related inline
functions from cache.h to read-cache.h. The purpose of the
read-cache-ll.h/read-cache.h split is that about 70% of the sites don't
need the inline functions and the extra headers they include.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When `diff.ignoreSubmodules = all` is set and submodule commits are
manually staged (e.g. via `git-update-index`), `git-commit` should
record the commit with updated submodules.
`index_differs_from` is called from `prepare_to_commit` with flags set to
`override_submodule_config = 1`. `index_differs_from` then merges the
default diff flags and passed flags.
When `diff.ignoreSubmodules` is set to "all", `flags` ends up having
both `override_submodule_config` and `ignore_submodules` set to 1. This
results in `git-commit` ignoring staged commits.
This patch restores original `flags.ignore_submodule` if
`flags.override_submodule_config` is set.
Signed-off-by: Josip Sokcevic <sokcevic@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dozens of files made use of trace and trace2 functions, without
explicitly including trace.h or trace2.h. This made it more difficult
to find which files could remove a dependence on cache.h. Make C files
explicitly include trace.h or trace2.h if they are using them.
Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ab/remove-implicit-use-of-the-repository:
libs: use "struct repository *" argument, not "the_repository"
post-cocci: adjust comments for recent repo_* migration
cocci: apply the "revision.h" part of "the_repository.pending"
cocci: apply the "rerere.h" part of "the_repository.pending"
cocci: apply the "refs.h" part of "the_repository.pending"
cocci: apply the "promisor-remote.h" part of "the_repository.pending"
cocci: apply the "packfile.h" part of "the_repository.pending"
cocci: apply the "pretty.h" part of "the_repository.pending"
cocci: apply the "object-store.h" part of "the_repository.pending"
cocci: apply the "diff.h" part of "the_repository.pending"
cocci: apply the "commit.h" part of "the_repository.pending"
cocci: apply the "commit-reach.h" part of "the_repository.pending"
cocci: apply the "cache.h" part of "the_repository.pending"
cocci: add missing "the_repository" macros to "pending"
cocci: sort "the_repository" rules by header
cocci: fix incorrect & verbose "the_repository" rules
cocci: remove dead rule from "the_repository.pending.cocci"
Apply the part of "the_repository.pending.cocci" pertaining to
"cache.h".
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dozens of files made use of gettext functions, without explicitly
including gettext.h. This made it more difficult to find which files
could remove a dependence on cache.h. Make C files explicitly include
gettext.h if they are using it.
However, while compat/fsmonitor/fsm-ipc-darwin.c should also gain an
include of gettext.h, it was left out to avoid conflicting with an
in-flight topic.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff code provides a format_callback interface, but not every
callback needs each parameter (e.g., the "opt" and "data" parameters are
frequently left unused). Likewise for the output_prefix callback, the
low-level change/add_remove interfaces, the callbacks used by
xdi_diff(), etc.
Mark unused arguments in the callback implementations to quiet
-Wunused-parameter.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update 'do_oneway_diff()' to perform a 'diff_tree_oid()' on removed sparse
directories, as it does for added or modified sparse directories (see
9eb00af562 (diff-lib: handle index diffs with sparse dirs, 2021-07-14)).
At the moment, this update is unreachable code because 'unpack_trees()'
(currently the only way 'oneway_diff()' can be called, via 'diff_cache()')
will always traverse trees down to the individual removed files of a deleted
sparse directory. A subsequent patch will change this to better preserve a
sparse index in other uses of 'unpack_tree()', e.g. 'git reset --hard'.
However, making that change without this patch would result in (among other
issues) 'git status' printing only the name of a deleted sparse directory,
not its contents. To avoid introducing that bug, 'do_oneway_diff()' is
updated before modifying 'unpack_trees()'.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a TODO comment indicating that we should release "diffopt" in
release_revisions(). In a preceding commit we started releasing the
"pruning" member of the same type, but handling "diffopt" will require
us to untangle the "no_free" conditions I added in e900d494dc (diff:
add an API for deferred freeing, 2021-02-11).
Let's leave a TODO comment to that effect, and so that we don't forget
refactor code that was changed to use release_revisions() in earlier
commits to stop using the "diffopt" member after a call to
release_revisions(). This works currently, but would become a logic
error as soon as we started freeing "diffopt". Doing that change now
doesn't harm anything, and future-proofs us against a later change to
release_revisions().
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extend the the release_revisions() function so that it frees the
"prune_data" in the "struct rev_info". This means that any code that
calls "release_revisions()" already can get rid of adjacent calls to
clear_pathspec().
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use release_revisions() for users of "struct rev_list" that reach into
the "struct rev_info" and clear the "prune_data" already.
In a subsequent commit we'll teach release_revisions() to clear this
itself, but in the meantime let's invoke release_revisions() here to
clear anything else we may have missed, and for reasons of having
consistent boilerplate.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The users of the revision.[ch] API's "struct rev_info" are a major
source of memory leaks in the test suite under SANITIZE=leak, which in
turn adds a lot of noise when trying to mark up tests with
"TEST_PASSES_SANITIZE_LEAK=true".
The users of that API are largely one-shot, e.g. "git rev-list" or
"git log", or the "git checkout" and "git stash" being modified here
For these callers freeing the memory is arguably a waste of time, but
in many cases they've actually been trying to free the memory, and
just doing that in a buggy manner.
Let's provide a release_revisions() function for these users, and
start migrating them over per the plan outlined in [1]. Right now this
only handles the "pending" member of the struct, but more will be
added in subsequent commits.
Even though we only clear the "pending" member now, let's not leave a
trap in code like the pre-image of index_differs_from(), where we'd
start doing the wrong thing as soon as the release_revisions() learned
to clear its "diffopt". I.e. we need to call release_revisions() after
we've inspected any state in "struct rev_info".
This leaves in place e.g. clear_pathspec(&rev.prune_data) in
stash_working_tree() in builtin/stash.c, subsequent commits will teach
release_revisions() to free "prune_data" and other members that in
some cases are individually cleared by users of "struct rev_info" by
reaching into its members. Those subsequent commits will remove the
relevant calls to e.g. clear_pathspec().
We avoid amending code in index_differs_from() in diff-lib.c as well
as wt_status_collect_changes_index(), has_unstaged_changes() and
has_uncommitted_changes() in wt-status.c in a way that assumes that we
are already clearing the "diffopt" member. That will be handled in a
subsequent commit.
1. https://lore.kernel.org/git/87a6k8daeu.fsf@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff --relative" segfaulted and/or produced incorrect result
when there are unmerged paths.
* dd/diff-files-unmerged-fix:
diff-lib: ignore paths that are outside $cwd if --relative asked
For diff family commands, we can tell them to exclude changes outside
of some directories if --relative is requested.
In diff_unmerge(), NULL will be returned if the requested path is
outside of the interesting directories, thus we'll run into NULL
pointer dereference in run_diff_files when trying to dereference
its return value.
Checking for return value of diff_unmerge before dereferencing
is not sufficient, though. Since, diff engine will try to work on such
pathspec later.
Let's not run diff on those unintesting entries, instead.
As a side effect, by skipping like that, we can save some CPU cycles.
Reported-by: Thomas De Zeeuw <thomas@slight.dev>
Tested-by: Carlo Arenas <carenas@gmail.com>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While comparing an index to a tree, we may see a sparse directory entry.
In this case, we should compare that portion of the tree to the tree
represented by that entry. This could include a new tree which needs to
be expanded to a full list of added files. It could also include an
existing tree, in which case all of the changes inside are important to
describe, including the modifications, additions, and deletions. Note
that the case where the tree has a path and the index does not remains
identical to before: the lack of a cache entry is the same with a sparse
index.
Use diff_tree_oid() appropriately to compute the diff.
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Up until recently, object IDs did not have an algorithm member, only a
hash. Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms. Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.
Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Validate that fsmonitor is valid to futureproof against bugs where
check_removed might be called from places that haven't refreshed.
Signed-off-by: Nipunn Koorapati <nipunn@dropbox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach git to honor fsmonitor rather than issuing an lstat
when checking for dirty local deletes. Eliminates O(files)
lstats during `git diff HEAD`
Signed-off-by: Nipunn Koorapati <nipunn@dropbox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
do_diff_cache() builds a struct rev_info to hand to diff_cache() from
scratch by initializing it using repo_init_revisions() and then
replacing its diffopt and prune_data members.
The diffopt member is initialized to a heap-allocated list of options,
though. Release it using diff_setup_done() before overwriting it.
The initial value of the prune_data member doesn't need to be released,
but the copy created using copy_pathspec() does. Clear it after use.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff" and other commands that share the same machinery to
compare with working tree files have been taught to take advantage
of the fsmonitor data when available.
* nk/diff-files-vs-fsmonitor:
p7519-fsmonitor: add a git add benchmark
p7519-fsmonitor: refactor to avoid code duplication
perf lint: add make test-lint to perf tests
t/perf: add fsmonitor perf test for git diff
t/perf/p7519-fsmonitor.sh: warm cache on first git status
t/perf/README: elaborate on output format
fsmonitor: use fsmonitor data in `git diff`
With fsmonitor enabled, the first call to match_stat_with_submodule
calls refresh_fsmonitor, incurring the overhead of reading the list of
updated files -- but run_diff_files does not respect the
CE_FSMONITOR_VALID flag.
Make use of the fsmonitor extension to skip lstat() calls on files
that fsmonitor judged as unmodified.
Notably, this change improves performance of the git shell prompt when
GIT_PS1_SHOWDIRTYSTATE is set.
Signed-off-by: Alex Vandiver <alexmv@dropbox.com>
Signed-off-by: Nipunn Koorapati <nipunn@dropbox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Get rid of 'dense' argument that is redundant for every function that has
'struct rev_info *rev' argument as well, as the value of 'dense' passed is
always taken from 'rev->dense_combined_merges' field.
The only place where this was not the case is in 'submodule.c' where
'diff_tree_combined_merge()' was called with '1' for 'dense' argument. However,
at that call the 'revs' instance used is local to the function, and we now just
set 'revs->dense_combined_merges' to 1 in this local instance.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"format-patch --range-diff=<prev> <origin>..HEAD" has been taught
not to ignore <origin> when <prev> is a single version.
* es/format-patch-interdiff-cleanup:
format-patch: use 'origin' as start of current-series-range when known
diff-lib: tighten show_interdiff()'s interface
diff: move show_interdiff() from its own file to diff-lib
