Commit Graph

65514 Commits

Author SHA1 Message Date
Junio C Hamano
98ab07ace5 Merge branch 'ws/fast-export-with-revision-options'
Use of certain "git rev-list" options with "git fast-export"
created nonsense results (the worst two of which being "--reverse"
and "--invert-grep --grep=<foo>").  The use of "--first-parent" is
made to behave a bit more sensible than before.

* ws/fast-export-with-revision-options:
  fast-export: fix surprising behavior with --first-parent
2022-01-10 11:52:50 -08:00
Junio C Hamano
b6f538f296 Merge branch 'js/l10n-mention-ngettext-early-in-readme'
Localization doc update.

* js/l10n-mention-ngettext-early-in-readme:
  l10n: README: call more attention to plural strings
2022-01-10 11:52:49 -08:00
Junio C Hamano
66f6c18e5b Merge branch 'jh/p4-human-unit-numbers'
The way "git p4" shows file sizes in its output has been updated to
use human-readable units.

* jh/p4-human-unit-numbers:
  git-p4: show progress as an integer
  git-p4: print size values in appropriate units
2022-01-10 11:52:49 -08:00
Junio C Hamano
09481fec21 Merge branch 'ds/sparse-checkout-malformed-pattern-fix'
Certain sparse-checkout patterns that are valid in non-cone mode
led to segfault in cone mode, which has been corrected.

* ds/sparse-checkout-malformed-pattern-fix:
  sparse-checkout: refuse to add to bad patterns
  sparse-checkout: fix OOM error with mixed patterns
  sparse-checkout: fix segfault on malformed patterns
2022-01-10 11:52:49 -08:00
Junio C Hamano
e83ba647f7 The seventh batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-05 14:01:31 -08:00
Junio C Hamano
9afe4d9f6b Merge branch 'rs/daemon-plug-leak'
Plug a memory leak.

* rs/daemon-plug-leak:
  daemon: plug memory leak on overlong path
2022-01-05 14:01:31 -08:00
Junio C Hamano
c91b0b7c72 Merge branch 'rs/pcre2-utf'
"git grep --perl-regexp" failed to match UTF-8 characters with
wildcard when the pattern consists only of ASCII letters, which has
been corrected.

* rs/pcre2-utf:
  grep/pcre2: factor out literal variable
  grep/pcre2: use PCRE2_UTF even with ASCII patterns
2022-01-05 14:01:31 -08:00
Junio C Hamano
5d522cddfd Merge branch 'jc/t4204-do-not-write-git-on-upstream-of-pipe'
Test fixes.

* jc/t4204-do-not-write-git-on-upstream-of-pipe:
  t4204 is not sanitizer clean at all
2022-01-05 14:01:31 -08:00
Junio C Hamano
2043ce828e Merge branch 'rs/log-invert-grep-with-headers'
"git log --invert-grep --author=<name>" used to exclude commits
written by the given author, but now "--invert-grep" only affects
the matches made by the "--grep=<pattern>" option.

* rs/log-invert-grep-with-headers:
  log: let --invert-grep only invert --grep
2022-01-05 14:01:30 -08:00
Junio C Hamano
2a6c7f996e Merge branch 'gh/gpg-doc-markup-fix'
Doc markup fix.

* gh/gpg-doc-markup-fix:
  docs: add missing colon to Documentation/config/gpg.txt
2022-01-05 14:01:30 -08:00
Junio C Hamano
8292c148df Merge branch 'rs/t4202-invert-grep-test-fix'
Test fix.

* rs/t4202-invert-grep-test-fix:
  t4202: fix patternType setting in --invert-grep test
2022-01-05 14:01:30 -08:00
Junio C Hamano
88a516aca0 Merge branch 'ds/repack-fixlets'
Two fixes around "git repack".

* ds/repack-fixlets:
  repack: make '--quiet' disable progress
  repack: respect kept objects with '--write-midx -b'
2022-01-05 14:01:30 -08:00
Junio C Hamano
bb14cfdfd7 Merge branch 'jc/merge-detached-head-name'
The default merge message prepared by "git merge" records the name
of the current branch; the name can be overridden with a new option
to allow users to pretend a merge is made on a different branch.

* jc/merge-detached-head-name:
  merge: allow to pretend a merge is made into a different branch
2022-01-05 14:01:30 -08:00
Junio C Hamano
a165484047 Merge branch 'km/help-prompt-fix'
Among some code paths that ask an yes/no question, only one place
gave a prompt that looked different from the others, which has been
updated to match what the others create.

* km/help-prompt-fix:
  help: make auto-correction prompt more consistent
2022-01-05 14:01:29 -08:00
Junio C Hamano
d9fc3a987b Merge branch 'jv/use-larger-buffer-in-upload-pack'
"git upload-pack" (the other side of "git fetch") used a 8kB buffer
but most of its payload came on 64kB "packets".  The buffer size
has been enlarged so that such a packet fits.

* jv/use-larger-buffer-in-upload-pack:
  upload-pack.c: increase output buffer size
2022-01-05 14:01:29 -08:00
Junio C Hamano
76987b8628 Merge branch 'jk/ssh-signing-doc-markup-fix'
Docfix.

* jk/ssh-signing-doc-markup-fix:
  doc/config: mark ssh allowedSigners example as literal
2022-01-05 14:01:29 -08:00
Junio C Hamano
2b755b3371 Merge branch 'pw/diff-color-moved-fix'
Correctness and performance update to "diff --color-moved" feature.

* pw/diff-color-moved-fix:
  diff --color-moved: intern strings
  diff: use designated initializers for emitted_diff_symbol
  diff --color-moved-ws=allow-indentation-change: improve hash lookups
  diff --color-moved: stop clearing potential moved blocks
  diff --color-moved: shrink potential moved blocks as we go
  diff --color-moved: unify moved block growth functions
  diff --color-moved: call comparison function directly
  diff --color-moved-ws=allow-indentation-change: simplify and optimize
  diff: simplify allow-indentation-change delta calculation
  diff --color-moved: avoid false short line matches and bad zebra coloring
  diff --color-moved=zebra: fix alternate coloring
  diff --color-moved: rewind when discarding pmb
  diff --color-moved: factor out function
  diff --color-moved: clear all flags on blocks that are too short
  diff --color-moved: add perf tests
2022-01-05 14:01:29 -08:00
Junio C Hamano
ead6767ad7 Merge branch 'xw/am-empty'
"git am" learns "--empty=(stop|drop|keep)" option to tweak what is
done to a piece of e-mail without a patch in it.

* xw/am-empty:
  am: support --allow-empty to record specific empty patches
  am: support --empty=<option> to handle empty patches
  doc: git-format-patch: describe the option --always
2022-01-05 14:01:28 -08:00
Junio C Hamano
da81d473fc Merge branch 'en/keep-cwd'
Many git commands that deal with working tree files try to remove a
directory that becomes empty (i.e. "git switch" from a branch that
has the directory to another branch that does not would attempt
remove all files in the directory and the directory itself).  This
drops users into an unfamiliar situation if the command was run in
a subdirectory that becomes subject to removal due to the command.
The commands have been taught to keep an empty directory if it is
the directory they were started in to avoid surprising users.

* en/keep-cwd:
  t2501: simplify the tests since we can now assume desired behavior
  dir: new flag to remove_dir_recurse() to spare the original_cwd
  dir: avoid incidentally removing the original_cwd in remove_path()
  stash: do not attempt to remove startup_info->original_cwd
  rebase: do not attempt to remove startup_info->original_cwd
  clean: do not attempt to remove startup_info->original_cwd
  symlinks: do not include startup_info->original_cwd in dir removal
  unpack-trees: add special cwd handling
  unpack-trees: refuse to remove startup_info->original_cwd
  setup: introduce startup_info->original_cwd
  t2501: add various tests for removing the current working directory
2022-01-05 14:01:28 -08:00
Junio C Hamano
d0c99fcc61 Merge branch 'jc/flex-array-definition'
The conditions to choose different definitions of the FLEX_ARRAY
macro for vendor compilers has been simplified to make it easier to
maintain.

* jc/flex-array-definition:
  flex-array: simplify compiler-specific workaround
2022-01-05 14:01:27 -08:00
Junio C Hamano
b58e7bfcd7 Merge branch 'jh/p4-rcs-expansion-in-bytestring'
The RCS keyword substitution in "git p4" used to be done assuming
that the contents are UTF-8 text, which can trigger decoding
errors.  We now treat the contents as a bytestring for robustness
and correctness.

* jh/p4-rcs-expansion-in-bytestring:
  git-p4: resolve RCS keywords in bytes not utf-8
  git-p4: open temporary patch file for write only
  git-p4: add raw option to read_pipelines
  git-p4: pre-compile RCS keyword regexes
  git-p4: use with statements to close files after use in patchRCSKeywords
2022-01-05 14:01:27 -08:00
Junio C Hamano
dcc0cd074f The sixth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-03 16:24:15 -08:00
Junio C Hamano
2dc94da374 Merge branch 'en/sparse-checkout-set'
The "init" and "set" subcommands in "git sparse-checkout" have been
unified for a better user experience and performance.

* en/sparse-checkout-set:
  sparse-checkout: remove stray trailing space
  clone: avoid using deprecated `sparse-checkout init`
  Documentation: clarify/correct a few sparsity related statements
  git-sparse-checkout.txt: update to document init/set/reapply changes
  sparse-checkout: enable reapply to take --[no-]{cone,sparse-index}
  sparse-checkout: enable `set` to initialize sparse-checkout mode
  sparse-checkout: split out code for tweaking settings config
  sparse-checkout: disallow --no-stdin as an argument to set
  sparse-checkout: add sanity-checks on initial sparsity state
  sparse-checkout: break apart functions for sparse_checkout_(set|add)
  sparse-checkout: pass use_stdin as a parameter instead of as a global
2022-01-03 16:24:15 -08:00
Junio C Hamano
4f4b18497a Merge branch 'es/test-chain-lint'
Broken &&-chains in the test scripts have been corrected.

* es/test-chain-lint:
  t6000-t9999: detect and signal failure within loop
  t5000-t5999: detect and signal failure within loop
  t4000-t4999: detect and signal failure within loop
  t0000-t3999: detect and signal failure within loop
  tests: simplify by dropping unnecessary `for` loops
  tests: apply modern idiom for exiting loop upon failure
  tests: apply modern idiom for signaling test failure
  tests: fix broken &&-chains in `{...}` groups
  tests: fix broken &&-chains in `$(...)` command substitutions
  tests: fix broken &&-chains in compound statements
  tests: use test_write_lines() to generate line-oriented output
  tests: simplify construction of large blocks of text
  t9107: use shell parameter expansion to avoid breaking &&-chain
  t6300: make `%(raw:size) --shell` test more robust
  t5516: drop unnecessary subshell and command invocation
  t4202: clarify intent by creating expected content less cleverly
  t1020: avoid aborting entire test script when one test fails
  t1010: fix unnoticed failure on Windows
  t/lib-pager: use sane_unset() to avoid breaking &&-chain
2022-01-03 16:24:15 -08:00
Junio C Hamano
0dc90d954d Merge branch 'ns/tmp-objdir'
New interface into the tmp-objdir API to help in-core use of the
quarantine feature.

* ns/tmp-objdir:
  tmp-objdir: disable ref updates when replacing the primary odb
  tmp-objdir: new API for creating temporary writable databases
2022-01-03 16:24:15 -08:00
Junio C Hamano
8bb565d375 Merge branch 'jc/unleak-log'
"git format-patch" uses a single rev_info instance and then exits.
Mark the structure with UNLEAK() macro to squelch leak sanitizer.

* jc/unleak-log:
  format-patch: mark rev_info with UNLEAK
2022-01-03 16:24:14 -08:00
Derrick Stolee
a3eca58445 sparse-checkout: refuse to add to bad patterns
When in cone mode sparse-checkout, it is unclear how 'git
sparse-checkout add <dir1> ...' should behave if the existing
sparse-checkout file does not match the cone mode patterns. Change the
behavior to fail with an error message about the existing patterns.

Also, all cone mode patterns start with a '/' character, so add that
restriction. This is necessary for our example test 'cone mode: warn on
bad pattern', but also requires modifying the example sparse-checkout
file we use to test the warnings related to recognizing cone mode
patterns.

This error checking would cause a failure further down the test script
because of a test that adds non-cone mode patterns without cleaning them
up. Perform that cleanup as part of the test now.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-30 14:39:57 -08:00
Derrick Stolee
391c3a1020 sparse-checkout: fix OOM error with mixed patterns
Add a test to t1091-sparse-checkout-builtin.sh that would result in an
infinite loop and out-of-memory error before this change. The issue
relies on having non-cone-mode patterns while trying to modify the
patterns in cone-mode.

The fix is simple, allowing us to break from the loop when the input
path does not contain a slash, as the "dir" pattern we added does not.

This is only a fix to the critical out-of-memory error. A better
response to such a strange state will follow in a later change.

Reported-by: Calbabreaker <calbabreaker@gmail.com>
Helped-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-30 14:39:57 -08:00
Derrick Stolee
a481d4378c sparse-checkout: fix segfault on malformed patterns
Then core.sparseCheckoutCone is enabled, the sparse-checkout patterns are
used to populate two hashsets that accelerate pattern matching. If the user
modifies the sparse-checkout file outside of the 'sparse-checkout' builtin,
then strange patterns can happen, triggering some error checks.

One of these error checks is possible to hit when some special characters
exist in a line. A warning message is correctly written to stderr, but then
there is additional logic that attempts to remove the line from the hashset
and free the data. This leads to a segfault in the 'git sparse-checkout
list' command because it iterates over the contents of the hashset, which is
now invalid.

The fix here is to stop trying to remove from the hashset. In addition,
we disable cone mode sparse-checkout because of the malformed data. This
results in the pattern-matching working with a possibly-slower
algorithm, but using the patterns as they are in the sparse-checkout
file.

This also changes the behavior of commands such as 'git sparse-checkout
list' because the output patterns will be the contents of the
sparse-checkout file instead of the list of directories. This is an
existing behavior for other types of bad patterns.

Add a test that triggers the segfault without the code change.

Reported-by: John Burnett <johnburnett@johnburnett.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-30 14:39:57 -08:00
Elijah Newren
dfac9b609f sparse-checkout: remove stray trailing space
Reported-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-23 11:55:54 -08:00
Junio C Hamano
2ae0a9cb82 The fifth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-22 22:48:11 -08:00
Junio C Hamano
d52da62801 Merge branch 'es/chainlint'
The chainlint test script linter in the test suite has been updated.

* es/chainlint:
  chainlint.sed: stop splitting "(..." into separate lines "(" and "..."
  chainlint.sed: swallow comments consistently
  chainlint.sed: stop throwing away here-doc tags
  chainlint.sed: don't mistake `<< word` in string as here-doc operator
  chainlint.sed: make here-doc "<<-" operator recognition more POSIX-like
  chainlint.sed: drop subshell-closing ">" annotation
  chainlint.sed: drop unnecessary distinction between ?!AMP?! and ?!SEMI?!
  chainlint.sed: tolerate harmless ";" at end of last line in block
  chainlint.sed: improve ?!SEMI?! placement accuracy
  chainlint.sed: improve ?!AMP?! placement accuracy
  t/Makefile: optimize chainlint self-test
  t/chainlint/one-liner: avoid overly intimate chainlint.sed knowledge
  t/chainlint/*.test: generalize self-test commentary
  t/chainlint/*.test: fix invalid test cases due to mixing quote types
  t/chainlint/*.test: don't use invalid shell syntax
2021-12-22 22:48:11 -08:00
Junio C Hamano
62a3a27b91 Merge branch 'jz/apply-quiet-and-allow-empty'
"git apply" has been taught to ignore a message without a patch
with the "--allow-empty" option.  It also learned to honor the
"--quiet" option given from the command line.

* jz/apply-quiet-and-allow-empty:
  git-apply: add --allow-empty flag
  git-apply: add --quiet flag
2021-12-22 22:48:11 -08:00
Junio C Hamano
5536415551 Merge branch 'jk/limit-developers-to-gnu99'
Enable -std=gnu99 option in DEVELOPER builds.

* jk/limit-developers-to-gnu99:
  config.mak.dev: specify -std=gnu99 for gcc/clang
2021-12-22 22:48:11 -08:00
Junio C Hamano
67b7017593 Merge branch 'ab/common-main-cleanup'
Code clean-up.

* ab/common-main-cleanup:
  common-main.c: call exit(), don't return
2021-12-22 22:48:11 -08:00
Junio C Hamano
dcaf17c75d Merge branch 'ab/fetch-set-upstream-while-detached'
"git fetch --set-upstream" did not check if there is a current
branch, leading to a segfault when it is run on a detached HEAD,
which has been corrected.

* ab/fetch-set-upstream-while-detached:
  pull, fetch: fix segfault in --set-upstream option
2021-12-22 22:48:10 -08:00
Junio C Hamano
597af311a2 The fourth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-21 15:03:23 -08:00
Junio C Hamano
62e83d4f69 Merge branch 'js/scalar'
Add pieces from "scalar" to contrib/.

* js/scalar:
  scalar: implement the `version` command
  scalar: implement the `delete` command
  scalar: teach 'reconfigure' to optionally handle all registered enlistments
  scalar: allow reconfiguring an existing enlistment
  scalar: implement the `run` command
  scalar: teach 'clone' to support the --single-branch option
  scalar: implement the `clone` subcommand
  scalar: implement 'scalar list'
  scalar: let 'unregister' handle a deleted enlistment directory gracefully
  scalar: 'unregister' stops background maintenance
  scalar: 'register' sets recommended config and starts maintenance
  scalar: create test infrastructure
  scalar: start documenting the command
  scalar: create a rudimentary executable
  scalar: add a README with a roadmap
2021-12-21 15:03:17 -08:00
Junio C Hamano
8d2c37320b Merge branch 'ld/sparse-diff-blame'
Teach diff and blame to work well with sparse index.

* ld/sparse-diff-blame:
  blame: enable and test the sparse index
  diff: enable and test the sparse index
  diff: replace --staged with --cached in t1092 tests
  repo-settings: prepare_repo_settings only in git repos
  test-read-cache: set up repo after git directory
  commit-graph: return if there is no git directory
  git: ensure correct git directory setup with -h
2021-12-21 15:03:17 -08:00
Junio C Hamano
3f9d5059c6 Merge branch 'en/name-rev-shorter-output'
"git name-rev" has been tweaked to give output that is shorter and
easier to understand.

* en/name-rev-shorter-output:
  name-rev: prefer shorter names over following merges
2021-12-21 15:03:16 -08:00
Junio C Hamano
13fa77b689 Merge branch 'ak/protect-any-current-branch'
"git fetch" without the "--update-head-ok" option ought to protect
a checked out branch from getting updated, to prevent the working
tree that checks it out to go out of sync.  The code was written
before the use of "git worktree" got widespread, and only checked
the branch that was checked out in the current worktree, which has
been updated.
(originally called ak/fetch-not-overwrite-any-current-branch)

* ak/protect-any-current-branch:
  branch: protect branches checked out in all worktrees
  receive-pack: protect current branch for bare repository worktree
  receive-pack: clean dead code from update_worktree()
  fetch: protect branches checked out in all worktrees
  worktree: simplify find_shared_symref() memory ownership model
  branch: lowercase error messages
  receive-pack: lowercase error messages
  fetch: lowercase error messages
2021-12-21 15:03:16 -08:00
Junio C Hamano
ee1dc493d1 Merge branch 'fs/ssh-signing-other-keytypes'
The cryptographic signing using ssh keys can specify literal keys
for keytypes whose name do not begin with the "ssh-" prefix by
using the "key::" prefix mechanism (e.g. "key::ecdsa-sha2-nistp256").

* fs/ssh-signing-other-keytypes:
  ssh signing: make sign/amend test more resilient
  ssh signing: support non ssh-* keytypes
2021-12-21 15:03:16 -08:00
Junio C Hamano
d2f0b72759 Merge branch 'fs/ssh-signing-key-lifetime'
Extend the signing of objects with SSH keys and learn to pay
attention to the key validity time range when verifying.

* fs/ssh-signing-key-lifetime:
  ssh signing: verify ssh-keygen in test prereq
  ssh signing: make fmt-merge-msg consider key lifetime
  ssh signing: make verify-tag consider key lifetime
  ssh signing: make git log verify key lifetime
  ssh signing: make verify-commit consider key lifetime
  ssh signing: add key lifetime test prereqs
  ssh signing: use sigc struct to pass payload
  t/fmt-merge-msg: make gpgssh tests more specific
  t/fmt-merge-msg: do not redirect stderr
2021-12-21 15:03:15 -08:00
Junio C Hamano
3770c21be9 Merge branch 'jc/grep-patterntype-default-doc'
Doc update.

* jc/grep-patterntype-default-doc:
  grep: clarify what `grep.patternType=default` means
2021-12-21 15:03:15 -08:00
Junio C Hamano
00cbaf9362 Merge branch 'jk/log-decorate-opts-with-implicit-decorate'
When "git log" implicitly enabled the "decoration" processing
without being explicitly asked with "--decorate" option, it failed
to read and honor the settings given by the "--decorate-refs"
option.

* jk/log-decorate-opts-with-implicit-decorate:
  log: load decorations with --simplify-by-decoration
  log: handle --decorate-refs with userformat "%d"
2021-12-21 15:03:15 -08:00
Junio C Hamano
57f28f4094 Merge branch 'en/rebase-x-wo-git-dir-env'
"git rebase -x" by mistake started exporting the GIT_DIR and
GIT_WORK_TREE environment variables when the command was rewritten
in C, which has been corrected.

* en/rebase-x-wo-git-dir-env:
  sequencer: do not export GIT_DIR and GIT_WORK_TREE for 'exec'
2021-12-21 15:03:15 -08:00
Junio C Hamano
5a4069a1d8 Merge branch 'jc/c99-var-decl-in-for-loop'
Weather balloon to find compilers that do not grok variable
declaration in the for() loop.

* jc/c99-var-decl-in-for-loop:
  revision: use C99 declaration of variable in for() loop
2021-12-21 15:03:15 -08:00
Junio C Hamano
a0f5ca94dd Merge branch 'pw/xdiff-classify-record-in-histogram'
"diff --histogram" optimization.

* pw/xdiff-classify-record-in-histogram:
  xdiff: drop unused flags parameter from recs_match
  xdiff: drop xpparam_t parameter from histogram cmp_recs()
  xdiff: drop CMP_ENV macro from xhistogram
  xdiff: simplify comparison
  xdiff: avoid unnecessary memory allocations
  diff histogram: intern strings
2021-12-21 15:03:14 -08:00
Josh Steadmon
786eb1ba39 l10n: README: call more attention to plural strings
In po/README.md, we point core developers to gettext's "Preparing
Strings" documentation for advice on marking strings for translation.
However, this doc doesn't really discuss the issues around plural form
translation, which can make it seem that nothing special needs to be
done in this case.

Add a specific callout here about marking plural-form strings so that
the advice later on in the README is not overlooked.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-21 12:55:28 -08:00
William Sprent
726a228dfb fast-export: fix surprising behavior with --first-parent
The revision traversal machinery typically processes and returns all
children before any parent.  fast-export needs to operate in the
reverse fashion, handling parents before any of their children in
order to build up the history starting from the root commit(s).  This
would be a clear case where we could just use the revision traversal
machinery's "reverse" option to achieve this desired affect.

However, this wasn't what the code did.  It added its own array for
queuing.  The obvious hand-rolled solution would be to just push all
the commits into the array and then traverse afterwards, but it didn't
quite do that either.  It instead attempted to process anything it
could as soon as it could, and once it could, check whether it could
process anything that had been queued.  As far as I can tell, this was
an effort to save a little memory in the case of multiple root commits
since it could process some commits before queueing all of them.  This
involved some helper functions named has_unshown_parent() and
handle_tail().  For typical invocations of fast-export, this
alternative essentially amounted to a hand-rolled method of reversing
the commits -- it was a bunch of work to duplicate the revision
traversal machinery's "reverse" option.

This hand-rolled reversing mechanism is actually somewhat difficult to
reason about.  It takes some time to figure out how it ensures in
normal cases that it will actually process all traversed commits
(rather than just dropping some and not printing anything for them).

And it turns out there are some cases where the code does drop commits
without handling them, and not even printing an error or warning for
the user.  Due to the has_unshown_parent() checks, some commits could
be left in the array at the end of the "while...get_revision()" loop
which would be unprocessed.  This could be triggered for example with
    git fast-export main -- --first-parent
or non-sensical traversal rules such as
    git fast-export main -- --grep=Merge --invert-grep

While most traversals that don't include all parents should likely
trigger errors in fast-export (or at least require being used in
combination with --reference-excluded-parents), the --first-parent
traversal is at least reasonable and it'd be nice if it didn't just drop
commits. It'd also be nice for future readers of the code to have a
simpler "reverse traversal" mechanism. Use the "reverse" option of the
revision traversal machinery to achieve both.

Even for the non-sensical traversal flags like the --grep one above,
this would be an improvement. For example, in that case, the code
previously would have silently truncated history to only those commits
that do not have an ancestor containing "Merge" in their commit message.
After this code change, that case would include all commits without
"Merge" in their commit message -- but any commit that previously had a
"Merge"-mentioning parent would lose that parent
(likely resulting in many new root commits). While the new behavior is
still odd, it is at least understandable given that
--reference-excluded-parents is not the default.

Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: William Sprent <williams@unity3d.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-21 12:51:09 -08:00