Commit Graph

15012 Commits

Author SHA1 Message Date
Jonathan Nieder
b2a51c1b03 mergetool: do not enable hideResolved by default
When 98ea309b3f (mergetool: add hideResolved configuration,
2021-02-09) introduced the mergetool.hideResolved setting to reduce
the clutter in viewing non-conflicted sections of files in a
mergetool, it enabled it by default, explaining:

    No adverse effects were noted in a small survey of popular mergetools[1]
    so this behavior defaults to `true`.

In practice, alas, adverse effects do appear.  A few issues:

1. No indication is shown in the UI that the base, local, and remote
   versions shown have been modified by additional resolution.  This
   is inherent in the design: the idea of mergetool.hideResolved is to
   convince a mergetool that expects pristine local, base, and remote
   files to show partially resolved verisons of those files instead;
   there is no additional source of information accessible to the
   mergetool to see where the resolution has happened.

   (By contrast, a mergetool generating the partial resolution from
   conflict markers for itself would be able to hilight the resolved
   sections with a different color.)

   A user accustomed to seeing the files without partial resolution
   gets no indication that this behavior has changed when they upgrade
   Git.

2. If the computed merge did not line up the files correctly (for
   example due to repeated sections in the file), the partially
   resolved files can be misleading and do not have enough information
   to reconstruct what happened and compute the correct merge result.

3. Resolving a conflict can involve information beyond the textual
   conflict.  For example, if the local and remote versions added
   overlapping functionality in different ways, seeing the full
   unresolved versions of each alongside the base gives information
   about each side's intent that makes it possible to come up with a
   resolution that combines those two intents.  By contrast, when
   starting with partially resolved versions of those files, one can
   produce a subtly wrong resolution that includes redundant extra
   code added by one side that is not needed in the approach taken
   on the other.

All that said, a user wanting to focus on textual conflicts with
reduced clutter can still benefit from mergetool.hideResolved=true as
a way to deemphasize sections of the code that resolve cleanly without
requiring any changes to the invoked mergetool.  The caveats described
above are reduced when the user has explicitly turned this on, because
then the user is aware of them.

Flip the default to 'false'.

Reported-by: Dana Dahlstrom <dahlstrom@google.com>
Helped-by: Seth House <seth@eseth.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-13 15:30:29 -08:00
René Scharfe
96099726dd archive: expand only a single %(describe) per archive
Every %(describe) placeholder in $Format:...$ strings in files with the
attribute export-subst is expanded by calling git describe.  This can
potentially result in a lot of such calls per archive.  That's OK for
local repositories under control of the user of git archive, but could
be a problem for hosted repositories.

Expand only a single %(describe) placeholder per archive for now to
avoid denial-of-service attacks.  We can make this limit configurable
later if needed, but let's start out simple.

Reported-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-11 13:22:44 -08:00
Junio C Hamano
13d7ab6b5d Git 2.31-rc2 2021-03-08 16:09:43 -08:00
Junio C Hamano
56a57652ef Sync with Git 2.30.2 for CVE-2021-21300
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-08 16:09:07 -08:00
Denton Liu
0af760e261 stash show: learn stash.showIncludeUntracked
The previous commit teaches `git stash show --include-untracked`. It
may be desirable for a user to be able to always enable the
--include-untracked behavior. Teach the stash.showIncludeUntracked
config option which allows users to do this in a similar manner to
stash.showPatch.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05 14:31:27 -08:00
Denton Liu
d3c7bf73bd stash show: teach --include-untracked and --only-untracked
Stash entries can be made with untracked files via
`git stash push --include-untracked`. However, because the untracked
files are stored in the third parent of the stash entry and not the
stash entry itself, running `git stash show` does not include the
untracked files as part of the diff.

With --include-untracked, untracked paths, which are recorded in the
third-parent if it exists, are shown in addition to the paths that have
modifications between the stash base and the working tree in the stash.

It is possible to manually craft a malformed stash entry where duplicate
untracked files in the stash entry will mask tracked files. We detect
and error out in that case via a custom unpack_trees() callback:
stash_worktree_untracked_merge().

Also, teach stash the --only-untracked option which only shows the
untracked files of a stash entry. This is similar to `git show stash^3`
but it is nice to provide a convenient abstraction for it so that users
do not have to think about the underlying implementation.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-05 14:31:26 -08:00
Junio C Hamano
be7935ed8b Merged the open-eintr workaround for macOS
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-04 15:42:50 -08:00
Elijah Newren
58d581c344 Documentation/RelNotes: improve release note for rename detection work
There were some early changes in the 2.31 cycle to optimize some setup
in diffcore-rename.c[1], some later changes to measure performance[2],
and finally some significant changes to improve rename detection
performance.  The final one was merged with the note

   Performance optimization work on the rename detection continues.

That works for the commit log, but feels misleading as a release note
since all the changes were within one cycle.  Simplify this to just

   Performance improvements for rename detection.

The former wording could be seen as hinting that more performance
improvements will come in 2.32, which is true, but we can just cover
those in the 2.32 release notes when the time comes.

[1] a5ac31b5b1 (Merge branch 'en/diffcore-rename', 2021-01-25)
[2] d3a035b055 (Merge branch 'en/merge-ort-perf', 2021-02-11)
[3] 12bd17521c (Merge branch 'en/diffcore-rename', 2021-03-01)

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-04 15:38:11 -08:00
Julien Richard
ea7e63921c doc: .gitignore documentation typofix
Signed-off-by: Julien Richard <julien.richard@ubisoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-03 17:16:48 -08:00
Denton Liu
f451960708 git-cat-file.txt: remove references to "sha1"
As part of the hash-transition, git can operate on more than just SHA-1
repositories. Replace "sha1"-specific documentation with hash-agnostic
terminology.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-03 16:43:06 -08:00
Denton Liu
4f0ba2d533 git-cat-file.txt: monospace args, placeholders and filenames
In modern documentation, args, placeholders and filenames are
monospaced. Apply monospace formatting to these objects.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-03 16:43:03 -08:00
Junio C Hamano
ec125d1bc1 Hopefully the last batch before -rc1
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-01 14:02:58 -08:00
Junio C Hamano
28714238c8 Merge branch 'hv/trailer-formatting'
The logic to handle "trailer" related placeholders in the
"--format=" mechanisms in the "log" family and "for-each-ref"
family is getting unified.

* hv/trailer-formatting:
  ref-filter: use pretty.c logic for trailers
  pretty.c: capture invalid trailer argument
  pretty.c: refactor trailer logic to `format_set_trailers_options()`
  t6300: use function to test trailer options
2021-03-01 14:02:58 -08:00
Junio C Hamano
18aabfaee5 Merge branch 'hn/reftable-tables-doc-update'
Documentation update.

* hn/reftable-tables-doc-update:
  doc/reftable: document how to handle windows
2021-03-01 14:02:57 -08:00
Junio C Hamano
6ee353d42f Merge branch 'jt/transfer-fsck-across-packs'
The approach to "fsck" the incoming objects in "index-pack" is
attractive for performance reasons (we have them already in core,
inflated and ready to be inspected), but fundamentally cannot be
applied fully when we receive more than one pack stream, as a tree
object in one pack may refer to a blob object in another pack as
".gitmodules", when we want to inspect blobs that are used as
".gitmodules" file, for example.  Teach "index-pack" to emit
objects that must be inspected later and check them in the calling
"fetch-pack" process.

* jt/transfer-fsck-across-packs:
  fetch-pack: print and use dangling .gitmodules
  fetch-pack: with packfile URIs, use index-pack arg
  http-fetch: allow custom index-pack args
  http: allow custom index-pack args
2021-03-01 14:02:57 -08:00
Junio C Hamano
660dd97a62 Merge branch 'ds/chunked-file-api'
The common code to deal with "chunked file format" that is shared
by the multi-pack-index and commit-graph files have been factored
out, to help codepaths for both filetypes to become more robust.

* ds/chunked-file-api:
  commit-graph.c: display correct number of chunks when writing
  chunk-format: add technical docs
  chunk-format: restore duplicate chunk checks
  midx: use 64-bit multiplication for chunk sizes
  midx: use chunk-format read API
  commit-graph: use chunk-format read API
  chunk-format: create read chunk API
  midx: use chunk-format API in write_midx_internal()
  midx: drop chunk progress during write
  midx: return success/failure in chunk write methods
  midx: add num_large_offsets to write_midx_context
  midx: add pack_perm to write_midx_context
  midx: add entries to write_midx_context
  midx: use context in write_midx_pack_names()
  midx: rename pack_info to write_midx_context
  commit-graph: use chunk-format write API
  chunk-format: create chunk format write API
  commit-graph: anonymize data in chunk_write_fn
2021-03-01 14:02:57 -08:00
Junio C Hamano
12bd17521c Merge branch 'en/diffcore-rename'
Performance optimization work on the rename detection continues.

* en/diffcore-rename:
  merge-ort: call diffcore_rename() directly
  gitdiffcore doc: mention new preliminary step for rename detection
  diffcore-rename: guide inexact rename detection based on basenames
  diffcore-rename: complete find_basename_matches()
  diffcore-rename: compute basenames of source and dest candidates
  t4001: add a test comparing basename similarity and content similarity
  diffcore-rename: filter rename_src list when possible
  diffcore-rename: no point trying to find a match better than exact
2021-03-01 14:02:56 -08:00
René Scharfe
273c9901c2 pretty: document multiple %(describe) being inconsistent
Each %(describe) placeholder is expanded using a separate git describe
call.  Their outputs depend on the tags present at the time, so there's
no consistency guarantee.  Document that fact.

Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-01 09:50:27 -08:00
Patrick Steinhardt
23c781f173 githooks.txt: clarify documentation on reference-transaction hook
The reference-transaction hook doesn't clearly document its scope and
what values it receives as input. Document it to make it less surprising
and clearly delimit its (current) scope.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-01 09:02:01 -08:00
Patrick Steinhardt
5f308a89d8 githooks.txt: replace mentions of SHA-1 specific properties
The githooks(5) documentation states in several places that the hook
will receive a SHA-1 or hashes of 40 characters length. Given that we're
transitioning to a world where both SHA-1 and SHA-256 are supported,
this is inaccurate.

Fix the issue by replacing mentions of SHA-1 with "object name" and not
explicitly mentioning the hash size.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-01 09:02:01 -08:00
Elijah Newren
37a2514364 diffcore-rename: use directory rename guided basename comparisons
A previous commit noted that it is very common for people to move files
across directories while keeping their filename the same.  The last few
commits took advantage of this and showed that we can accelerate rename
detection significantly using basenames; since files with the same
basename serve as likely rename candidates, we can check those first and
remove them from the rename candidate pool if they are sufficiently
similar.

Unfortunately, the previous optimization was limited by the fact that
the remaining basenames after exact rename detection are not always
unique.  Many repositories have hundreds of build files with the same
name (e.g. Makefile, .gitignore, build.gradle, etc.), and may even have
hundreds of source files with the same name.  (For example, the linux
kernel has 100 setup.c, 87 irq.c, and 112 core.c files.  A repository at
$DAYJOB has a lot of ObjectFactory.java and Plugin.java files).

For these files with non-unique basenames, we are faced with the task of
attempting to determine or guess which directory they may have been
relocated to.  Such a task is precisely the job of directory rename
detection.  However, there are two catches: (1) the directory rename
detection code has traditionally been part of the merge machinery rather
than diffcore-rename.c, and (2) directory rename detection currently
runs after regular rename detection is complete.  The 1st catch is just
an implementation issue that can be overcome by some code shuffling.
The 2nd requires us to add a further approximation: we only have access
to exact renames at this point, so we need to do directory rename
detection based on just exact renames.  In some cases we won't have
exact renames, in which case this extra optimization won't apply.  We
also choose to not apply the optimization unless we know that the
underlying directory was removed, which will require extra data to be
passed in to diffcore_rename_extended().  Also, even if we get a
prediction about which directory a file may have relocated to, we will
still need to check to see if there is a file in the predicted
directory, and then compare the two files to see if they meet the higher
min_basename_score threshold required for marking the two files as
renames.

This commit introduces an idx_possible_rename() function which will
do this directory rename detection for us and give us the index within
rename_dst of the resulting filename.  For now, this function is
hardcoded to return -1 (not found) and just hooks up how its results
would be used once we have a more complete implementation in place.

Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-26 17:53:11 -08:00
Junio C Hamano
225365fb51 Git 2.31-rc0
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-25 16:43:33 -08:00
Junio C Hamano
09e72204f8 Merge branch 'dl/doc-config-camelcase'
A handful of multi-word configuration variable names in
documentation that are spelled in all lowercase have been corrected
to use the more canonical camelCase.

* dl/doc-config-camelcase:
  index-format doc: camelCase core.excludesFile
  blame-options.txt: camelcase blame.blankBoundary
  i18n.txt: camel case and monospace "i18n.commitEncoding"
2021-02-25 16:43:32 -08:00
Junio C Hamano
d228b6b231 Merge branch 'ug/doc-commit-approxidate'
Doc update.

* ug/doc-commit-approxidate:
  doc: mention approxidates for git-commit --date
2021-02-25 16:43:32 -08:00
Junio C Hamano
682bbad64d Merge branch 'ah/rebase-no-fork-point-config'
"git rebase --[no-]fork-point" gained a configuration variable
rebase.forkPoint so that users do not have to keep specifying a
non-default setting.

* ah/rebase-no-fork-point-config:
  rebase: add a config option for --no-fork-point
2021-02-25 16:43:31 -08:00
Junio C Hamano
6eea44cee1 Merge branch 'zh/difftool-skip-to'
"git difftool" learned "--skip-to=<path>" option to restart an
interrupted session from an arbitrary path.

* zh/difftool-skip-to:
  difftool.c: learn a new way start at specified file
2021-02-25 16:43:31 -08:00
Junio C Hamano
ccf6861b72 Merge branch 'cw/pack-config-doc'
Doc update.

* cw/pack-config-doc:
  doc: mention bigFileThreshold for packing
2021-02-25 16:43:31 -08:00
Junio C Hamano
dddb420535 Merge branch 'jc/maint-column-doc-typofix'
Doc update.

* jc/maint-column-doc-typofix:
  Documentation: typofix --column description
2021-02-25 16:43:30 -08:00
Junio C Hamano
2638e33c82 Merge branch 'ma/doc-markup-fix'
Docfix.

* ma/doc-markup-fix:
  gitmailmap.txt: fix rendering of e-mail addresses
  git.txt: fix monospace rendering
  rev-list-options.txt: fix rendering of bonus paragraph
2021-02-25 16:43:30 -08:00
Junio C Hamano
845d6030f8 Merge branch 'jc/diffcore-rotate'
"git {diff,log} --{skip,rotate}-to=<path>" allows the user to
discard diff output for early paths or move them to the end of the
output.

* jc/diffcore-rotate:
  diff: --{rotate,skip}-to=<path>
2021-02-25 16:43:30 -08:00
Junio C Hamano
f47c3328ef Merge branch 'js/doc-proto-v2-response-end'
Docfix.

* js/doc-proto-v2-response-end:
  doc: fix naming of response-end-pkt
2021-02-25 16:43:30 -08:00
Junio C Hamano
d590ae5560 Merge branch 'mz/doc-notes-are-not-anchors'
Objects that lost references can be pruned away, even when they
have notes attached to it (and these notes will become dangling,
which in turn can be pruned with "git notes prune").  This has been
clarified in the documentation.

* mz/doc-notes-are-not-anchors:
  docs: clarify that refs/notes/ do not keep the attached objects alive
2021-02-25 16:43:29 -08:00
Junio C Hamano
6fe12b5215 Merge branch 'jk/rev-list-disk-usage'
"git rev-list" command learned "--disk-usage" option.

* jk/rev-list-disk-usage:
  docs/rev-list: add some examples of --disk-usage
  docs/rev-list: add an examples section
  rev-list: add --disk-usage option for calculating disk usage
  t: add --no-tag option to test_commit
2021-02-25 16:43:29 -08:00
Derrick Stolee
702110aac6 commit-graph: use config to specify generation type
We have two established generation number versions:

 1: topological levels
 2: corrected commit dates

The corrected commit dates are enabled by default, but they also write
extra data in the GDAT and GDOV chunks. Services that host Git data
might want to have more control over when this feature rolls out than
just updating the Git binaries.

Add a new "commitGraph.generationVersion" config option that specifies
the intended generation number version. If this value is less than 2,
then the GDAT chunk is never written _or read_ from an existing file.

This can replace our use of the GIT_TEST_COMMIT_GRAPH_NO_GDAT
environment variable in the test suite. Remove it.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-25 15:10:41 -08:00
Junio C Hamano
11875561bf Merge branch 'ds/chunked-file-api' into tb/reverse-midx
* ds/chunked-file-api:
  commit-graph.c: display correct number of chunks when writing
  chunk-format: add technical docs
  chunk-format: restore duplicate chunk checks
  midx: use 64-bit multiplication for chunk sizes
  midx: use chunk-format read API
  commit-graph: use chunk-format read API
  chunk-format: create read chunk API
  midx: use chunk-format API in write_midx_internal()
  midx: drop chunk progress during write
  midx: return success/failure in chunk write methods
  midx: add num_large_offsets to write_midx_context
  midx: add pack_perm to write_midx_context
  midx: add entries to write_midx_context
  midx: use context in write_midx_pack_names()
  midx: rename pack_info to write_midx_context
  commit-graph: use chunk-format write API
  chunk-format: create chunk format write API
  commit-graph: anonymize data in chunk_write_fn
2021-02-24 15:26:14 -08:00
Junio C Hamano
7dd0eaa39c index-format doc: camelCase core.excludesFile
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Junio C Hamano
edaf10dd26 blame-options.txt: camelcase blame.blankBoundary
All other references to blame.* configuration variables are
camelCased already.  Update this one to match.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Denton Liu
77645b5daa i18n.txt: camel case and monospace "i18n.commitEncoding"
In 95791be750 (doc: camelCase the i18n config variables to improve
readability, 2017-07-17), the other i18n config variables were
camel cased. However, this one instance was missed.

Camel case and monospace "i18n.commitEncoding" so that it matches the
surrounding text.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
[jc: fixed 3 other mistakes that are exactly the same]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 15:21:25 -08:00
Alex Henrie
2803d800d2 rebase: add a config option for --no-fork-point
Some users (myself included) would prefer to have this feature off by
default because it can silently drop commits.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-24 11:49:10 -08:00
Jeff King
01168a9d89 doc: mention approxidates for git-commit --date
We describe the more strict date formats accepted by GIT_COMMITTER_DATE,
etc, but the --date option also allows the looser approxidate formats,
as well. Unfortunately we don't have a good or complete reference for
this format, but let's at least mention that it _is_ looser, and give a
few examples.

If we ever write separate, more complete date-format documentation, we
should refer to it from here.

Based-on-a-patch-by: Utku Gultopu <ugultopu@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 13:33:02 -08:00
Han-Wen Nienhuys
00f68732e5 doc/reftable: document how to handle windows
On Windows we can't delete or overwrite files opened by other processes. Here we
sketch how to handle this situation.

We propose to use a random element in the filename. It's possible to design an
alternate solution based on counters, but that would assign semantics to the
filenames that complicates implementation.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-23 10:01:21 -08:00
Taylor Blau
0fabafd0b9 builtin/repack.c: add '--geometric' option
Often it is useful to both:

  - have relatively few packfiles in a repository, and

  - avoid having so few packfiles in a repository that we repack its
    entire contents regularly

This patch implements a '--geometric=<n>' option in 'git repack'. This
allows the caller to specify that they would like each pack to be at
least a factor times as large as the previous largest pack (by object
count).

Concretely, say that a repository has 'n' packfiles, labeled P1, P2,
..., up to Pn. Each packfile has an object count equal to 'objects(Pn)'.
With a geometric factor of 'r', it should be that:

  objects(Pi) > r*objects(P(i-1))

for all i in [1, n], where the packs are sorted by

  objects(P1) <= objects(P2) <= ... <= objects(Pn).

Since finding a true optimal repacking is NP-hard, we approximate it
along two directions:

  1. We assume that there is a cutoff of packs _before starting the
     repack_ where everything to the right of that cut-off already forms
     a geometric progression (or no cutoff exists and everything must be
     repacked).

  2. We assume that everything smaller than the cutoff count must be
     repacked. This forms our base assumption, but it can also cause
     even the "heavy" packs to get repacked, for e.g., if we have 6
     packs containing the following number of objects:

       1, 1, 1, 2, 4, 32

     then we would place the cutoff between '1, 1' and '1, 2, 4, 32',
     rolling up the first two packs into a pack with 2 objects. That
     breaks our progression and leaves us:

       2, 1, 2, 4, 32
         ^

     (where the '^' indicates the position of our split). To restore a
     progression, we move the split forward (towards larger packs)
     joining each pack into our new pack until a geometric progression
     is restored. Here, that looks like:

       2, 1, 2, 4, 32  ~>  3, 2, 4, 32  ~>  5, 4, 32  ~> ... ~> 9, 32
         ^                   ^                ^                   ^

This has the advantage of not repacking the heavy-side of packs too
often while also only creating one new pack at a time. Another wrinkle
is that we assume that loose, indexed, and reflog'd objects are
insignificant, and lump them into any new pack that we create. This can
lead to non-idempotent results.

Suggested-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 23:30:52 -08:00
Taylor Blau
339bce27f4 builtin/pack-objects.c: add '--stdin-packs' option
In an upcoming commit, 'git repack' will want to create a pack comprised
of all of the objects in some packs (the included packs) excluding any
objects in some other packs (the excluded packs).

This caller could iterate those packs themselves and feed the objects it
finds to 'git pack-objects' directly over stdin, but this approach has a
few downsides:

  - It requires every caller that wants to drive 'git pack-objects' in
    this way to implement pack iteration themselves. This forces the
    caller to think about details like what order objects are fed to
    pack-objects, which callers would likely rather not do.

  - If the set of objects in included packs is large, it requires
    sending a lot of data over a pipe, which is inefficient.

  - The caller is forced to keep track of the excluded objects, too, and
    make sure that it doesn't send any objects that appear in both
    included and excluded packs.

But the biggest downside is the lack of a reachability traversal.
Because the caller passes in a list of objects directly, those objects
don't get a namehash assigned to them, which can have a negative impact
on the delta selection process, causing 'git pack-objects' to fail to
find good deltas even when they exist.

The caller could formulate a reachability traversal themselves, but the
only way to drive 'git pack-objects' in this way is to do a full
traversal, and then remove objects in the excluded packs after the
traversal is complete. This can be detrimental to callers who care
about performance, especially in repositories with many objects.

Introduce 'git pack-objects --stdin-packs' which remedies these four
concerns.

'git pack-objects --stdin-packs' expects a list of pack names on stdin,
where 'pack-xyz.pack' denotes that pack as included, and
'^pack-xyz.pack' denotes it as excluded. The resulting pack includes all
objects that are present in at least one included pack, and aren't
present in any excluded pack.

To address the delta selection problem, 'git pack-objects --stdin-packs'
works as follows. First, it assembles a list of objects that it is going
to pack, as above. Then, a reachability traversal is started, whose tips
are any commits mentioned in included packs. Upon visiting an object, we
find its corresponding object_entry in the to_pack list, and set its
namehash parameter appropriately.

To avoid the traversal visiting more objects than it needs to, the
traversal is halted upon encountering an object which can be found in an
excluded pack (by marking the excluded packs as kept in-core, and
passing --no-kept-objects=in-core to the revision machinery).

This can cause the traversal to halt early, for example if an object in
an included pack is an ancestor of ones in excluded packs. But stopping
early is OK, since filling in the namehash fields of objects in the
to_pack list is only additive (i.e., having it helps the delta selection
process, but leaving it blank doesn't impact the correctness of the
resulting pack).

Even still, it is unlikely that this hurts us much in practice, since
the 'git repack --geometric' caller (which is introduced in a later
commit) marks small packs as included, and large ones as excluded.
During ordinary use, the small packs usually represent pushes after a
large repack, and so are unlikely to be ancestors of objects that
already exist in the repository.

(I found it convenient while developing this patch to have 'git
pack-objects' report the number of objects which were visited and got
their namehash fields filled in during traversal. This is also included
in the below patch via trace2 data lines).

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 23:30:52 -08:00
Junio C Hamano
966e671106 The tenth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 16:12:43 -08:00
Junio C Hamano
dc24948be9 Merge branch 'ta/hash-function-transition-doc'
Update formatting and grammar of the hash transition plan
documentation, plus some updates.

* ta/hash-function-transition-doc:
  doc: use https links
  doc hash-function-transition: move rationale upwards
  doc hash-function-transition: fix incomplete sentence
  doc hash-function-transition: use upper case consistently
  doc hash-function-transition: use SHA-1 and SHA-256 consistently
  doc hash-function-transition: fix asciidoc output
2021-02-22 16:12:43 -08:00
Junio C Hamano
b9554c03a0 Merge branch 'dl/stash-cleanup'
Documentation, code and test clean-up around "git stash".

* dl/stash-cleanup:
  stash: declare ref_stash as an array
  t3905: use test_cmp() to check file contents
  t3905: replace test -s with test_file_not_empty
  t3905: remove nested git in command substitution
  t3905: move all commands into test cases
  t3905: remove spaces after redirect operators
  git-stash.txt: be explicit about subcommand options
2021-02-22 16:12:42 -08:00
ZheNing Hu
1c881026a1 difftool.c: learn a new way start at specified file
`git difftool` only allow us to select file to view in turn.
If there is a commit with many files and we exit in the middle,
we will have to traverse list again to get the file diff which
we want to see. Therefore,teach the command an option
`--skip-to=<path>` to allow the user to say that diffs for earlier
paths are not interesting (because they were already seen in an
earlier session) and start this session with the named path.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:35:49 -08:00
Christian Walther
3a837b58e3 doc: mention bigFileThreshold for packing
Knowing about the core.bigFileThreshold configuration variable is
helpful when examining pack file size differences between repositories.
Add a reference to it to the manpages a user is likely to read in this
situation.

Capitalize CONFIGURATION for consistency with other pages having such a
section.

Signed-off-by: Christian Walther <cwalther@gmx.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 13:18:30 -08:00
Jonathan Tan
5476e1efde fetch-pack: print and use dangling .gitmodules
Teach index-pack to print dangling .gitmodules links after its "keep" or
"pack" line instead of declaring an error, and teach fetch-pack to check
such lines printed.

This allows the tree side of the .gitmodules link to be in one packfile
and the blob side to be in another without failing the fsck check,
because it is now fetch-pack which checks such objects after all
packfiles have been downloaded and indexed (and not index-pack on an
individual packfile, as it is before this commit).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 12:07:40 -08:00
Jonathan Tan
27e35ba6c6 http-fetch: allow custom index-pack args
This is the next step in teaching fetch-pack to pass its index-pack
arguments when processing packfiles referenced by URIs.

The "--keep" in fetch-pack.c will be replaced with a full message in a
subsequent commit.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 12:07:40 -08:00