Commit Graph

58723 Commits

Author SHA1 Message Date
Junio C Hamano
4a5c3e10f2 Merge branch 'rs/show-progress-in-dumb-http-fetch'
"git fetch" over HTTP walker protocol did not show any progress
output.  We inherently do not know how much work remains, but still
we can show something not to bore users.

* rs/show-progress-in-dumb-http-fetch:
  remote-curl: show progress for fetches over dumb HTTP
2020-03-09 11:21:21 -07:00
Junio C Hamano
3658d77f8e Merge branch 'hd/show-one-mergetag-fix'
"git show" and others gave an object name in raw format in its
error output, which has been corrected to give it in hex.

* hd/show-one-mergetag-fix:
  show_one_mergetag: print non-parent in hex form.
2020-03-09 11:21:21 -07:00
Junio C Hamano
6125104b88 Merge branch 'rt/format-zero-length-fix'
Recently we inadvertently added a few instances of using 0-width
format string to functions that we mark as printf-like without any
developers noticing.  The root cause was that the compiler warning
that is triggered by this is almost always useless and we disabled
the warning in our developer builds, but not for general public.
The new instances have been corrected, and the warning has been
resurrected in the developer builds.

* rt/format-zero-length-fix:
  config.mak.dev: re-enable -Wformat-zero-length
  rebase-interactive.c: silence format-zero-length warnings
2020-03-09 11:21:21 -07:00
Junio C Hamano
1ac37deba2 Merge branch 'am/mingw-poll-fix'
MinGW's poll() emulation has been improved.

* am/mingw-poll-fix:
  mingw: workaround for hangs when sending STDIN
2020-03-09 11:21:20 -07:00
Junio C Hamano
cf372dc815 Merge branch 'en/test-cleanup'
Test cleanup.

* en/test-cleanup:
  t6020: new test with interleaved lexicographic ordering of directories
  t6022, t6046: test expected behavior instead of testing a proxy for it
  t3035: prefer test_must_fail to bash negation for git commands
  t6020, t6022, t6035: update merge tests to use test helper functions
  t602[1236], t6034: modernize test formatting
2020-03-09 11:21:20 -07:00
Junio C Hamano
d1075adfdf Merge branch 'en/merge-path-collision'
Handling of conflicting renames in merge-recursive have further
been made consistent with how existing codepaths try to mimic what
is done to add/add conflicts.

* en/merge-path-collision:
  merge-recursive: apply collision handling unification to recursive case
2020-03-09 11:21:20 -07:00
Junio C Hamano
a4fd114ffc Merge branch 'kk/complete-diff-color-moved'
Completion update.

* kk/complete-diff-color-moved:
  completion: add diff --color-moved[-ws]
2020-03-09 11:21:20 -07:00
Junio C Hamano
a0d752c1a3 Merge branch 'rj/t1050-use-test-path-is-file'
Code cleanup.

* rj/t1050-use-test-path-is-file:
  t1050: replace test -f with test_path_is_file
2020-03-09 11:21:20 -07:00
Junio C Hamano
0e0d717537 Merge branch 'pb/am-show-current-patch'
"git am --short-current-patch" is a way to show the piece of e-mail
for the stopped step, which is not suitable to directly feed "git
apply" (it is designed to be a good "git am" input).  It learned a
new option to show only the patch part.

* pb/am-show-current-patch:
  am: support --show-current-patch=diff to retrieve .git/rebase-apply/patch
  am: support --show-current-patch=raw as a synonym for--show-current-patch
  am: convert "resume" variable to a struct
  parse-options: convert "command mode" to a flag
  parse-options: add testcases for OPT_CMDMODE()
2020-03-09 11:21:19 -07:00
Junio C Hamano
9b7f726dfc Merge branch 'am/pathspec-f-f-more'
"git rm" and "git stash" learns the new "--pathspec-from-file"
option.

* am/pathspec-f-f-more:
  stash push: support the --pathspec-from-file option
  stash: eliminate crude option parsing
  doc: stash: synchronize <pathspec> description
  doc: stash: document more options
  doc: stash: split options from description (2)
  doc: stash: split options from description (1)
  rm: support the --pathspec-from-file option
  doc: rm: synchronize <pathspec> description
2020-03-09 11:21:19 -07:00
Martin Ågren
4605a73073 t1091: don't grep for strerror() string
We grep for "File exists" in stderr of the failing `git sparse-checkout`
to make sure that it failed for the right reason. We expect the string
to show up there since we call `strerror(errno)` in
`unable_to_lock_message()` in lockfile.c.

On the NonStop platform, this fails because the error string is "File
already exists", which doesn't match our grepping.

See 9042140097 ("test-dir-iterator: do not assume errno values",
2019-07-30) for a somewhat similar fix. There, we patched a test helper,
which meant we had access to `errno` and could investigate it better in
the test helper instead of just outputting the numerical value and
evaluating it in the test script. The current situation is different,
since (short of modifying the lockfile machinery, e.g., to be more
verbose) we don't have more than the output from `strerror()` available.

Except we do: We prefix `strerror(errno)` with `_("Unable to create
'%s.lock': ")`. Let's grep for that part instead. It verifies that we
were indeed unable to create the lock file. (If that fails for some
other reason than the file existing, we really really should expect
other tests to fail as well.)

An alternative fix would be to loosen the expression a bit and grep for
"File.* exists" instead. There would be no guarantee that some other
implementation couldn't come up with another error string, That is, that
could be the first move in an endless game of whack-a-mole. Of course,
it could also take us from "99" to "100" percent of the platforms and
we'd never have this problem again. But since we have another way of
addressing this, let's not even try the "loosen it up a bit" strategy.

Reported-by: Randall S. Becker <rsbecker@nexbridge.com>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-09 08:05:13 -07:00
Junio C Hamano
076cbdcd73 Git 2.26-rc0
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-05 11:15:45 -08:00
Johannes Schindelin
0d65f3fb1a t5537: adjust test_oid label
We recently switched to using Perl instead of `sed` in the httpd-based
tests. Let's reflect that in the label we give the corresponding commit
hashes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-05 11:09:56 -08:00
Junio C Hamano
e63cefb024 Merge branch 'hi/gpg-use-check-signature'
"git merge signed-tag" while lacking the public key started to say
"No signature", which was utterly wrong.  This regression has been
reverted.

* hi/gpg-use-check-signature:
  Revert "gpg-interface: prefer check_signature() for GPG verification"
2020-03-05 10:43:05 -08:00
Junio C Hamano
5da7329e29 Merge branch 'rs/commit-graph-code-simplification'
Code simplfication.

* rs/commit-graph-code-simplification:
  commit-graph: use progress title directly
2020-03-05 10:43:04 -08:00
Junio C Hamano
0108fc1b46 Merge branch 'js/ci-windows-update'
Updates to the CI settings.

* js/ci-windows-update:
  Azure Pipeline: switch to the latest agent pools
  ci: prevent `perforce` from being quarantined
  t/lib-httpd: avoid using macOS' sed
2020-03-05 10:43:04 -08:00
Junio C Hamano
f3ccd9f0d9 Merge branch 'be/describe-multiroot'
"git describe" in a repository with multiple root commits sometimes
gave up looking for the best tag to describe a given commit with
too early, which has been adjusted.

* be/describe-multiroot:
  describe: don't abort too early when searching tags
2020-03-05 10:43:04 -08:00
Junio C Hamano
a6b4709302 Merge branch 'ag/rebase-remove-redundant-code'
Code reduction.

* ag/rebase-remove-redundant-code:
  builtin/rebase: remove a call to get_oid() on `options.switch_to'
2020-03-05 10:43:04 -08:00
Junio C Hamano
b22db265d6 Merge branch 'es/recursive-single-branch-clone'
"git clone --recurse-submodules --single-branch" now uses the same
single-branch option when cloning the submodules.

* es/recursive-single-branch-clone:
  clone: pass --single-branch during --recurse-submodules
  submodule--helper: use C99 named initializer
2020-03-05 10:43:03 -08:00
Junio C Hamano
e8e71848ea Merge branch 'jk/nth-packed-object-id'
Code cleanup to use "struct object_id" more by replacing use of
"char *sha1"

* jk/nth-packed-object-id:
  packfile: drop nth_packed_object_sha1()
  packed_object_info(): use object_id internally for delta base
  packed_object_info(): use object_id for returning delta base
  pack-check: push oid lookup into loop
  pack-check: convert "internal error" die to a BUG()
  pack-bitmap: use object_id when loading on-disk bitmaps
  pack-objects: use object_id struct in pack-reuse code
  pack-objects: convert oe_set_delta_ext() to use object_id
  pack-objects: read delta base oid into object_id struct
  nth_packed_object_oid(): use customary integer return
2020-03-05 10:43:03 -08:00
Junio C Hamano
a0ab37de61 Merge branch 'es/do-not-let-rebase-switch-to-protected-branch'
"git rebase BASE BRANCH" rebased/updated the tip of BRANCH and
checked it out, even when the BRANCH is checked out in a different
worktree.  This has been corrected.

* es/do-not-let-rebase-switch-to-protected-branch:
  rebase: refuse to switch to branch already checked out elsewhere
  t3400: make test clean up after itself
2020-03-05 10:43:03 -08:00
Junio C Hamano
4a2e91db65 Merge branch 'hv/receive-denycurrent-everywhere'
"git push" should stop from updating a branch that is checked out
when receive.denyCurrentBranch configuration is set, but it failed
to pay attention to checkouts in secondary worktrees.  This has
been corrected.

* hv/receive-denycurrent-everywhere:
  t2402: test worktree path when called in .git directory
  receive.denyCurrentBranch: respect all worktrees
  t5509: use a bare repository for test push target
  get_main_worktree(): allow it to be called in the Git directory
2020-03-05 10:43:03 -08:00
Junio C Hamano
49e5043b09 Merge branch 'es/worktree-avoid-duplication-fix'
In rare cases "git worktree add <path>" could think that <path>
was already a registered worktree even when it wasn't and refuse
to add the new worktree. This has been corrected.

* es/worktree-avoid-duplication-fix:
  worktree: don't allow "add" validation to be fooled by suffix matching
  worktree: add utility to find worktree by pathname
  worktree: improve find_worktree() documentation
2020-03-05 10:43:02 -08:00
Junio C Hamano
2cbb058669 Merge branch 'bc/wildcard-credential'
A configuration element used for credential subsystem can now use
wildcard pattern to specify for which set of URLs the entry
applies.

* bc/wildcard-credential:
  credential: allow wildcard patterns when matching config
  credential: use the last matching username in the config
  t0300: add tests for some additional cases
  t1300: add test for urlmatch with multiple wildcards
  mailmap: add an additional email address for brian m. carlson
2020-03-05 10:43:02 -08:00
Junio C Hamano
25063e2530 Merge branch 'mr/bisect-in-c-1'
Underlying machinery of "git bisect--helper" is being refactored
into pieces that are more easily reused.

* mr/bisect-in-c-1:
  bisect: libify `bisect_next_all`
  bisect: libify `handle_bad_merge_base` and its dependents
  bisect: libify `check_good_are_ancestors_of_bad` and its dependents
  bisect: libify `check_merge_bases` and its dependents
  bisect: libify `bisect_checkout`
  bisect: libify `exit_if_skipped_commits` to `error_if_skipped*` and its dependents
  bisect--helper: return error codes from `cmd_bisect__helper()`
  bisect: add enum to represent bisect returning codes
  bisect--helper: introduce new `decide_next()` function
  bisect: use the standard 'if (!var)' way to check for 0
  bisect--helper: change `retval` to `res`
  bisect--helper: convert `vocab_*` char pointers to char arrays
2020-03-05 10:43:02 -08:00
Junio C Hamano
f4d7dfce4d Merge branch 'ds/sparse-add'
"git sparse-checkout" learned a new "add" subcommand.

* ds/sparse-add:
  sparse-checkout: allow one-character directories in cone mode
  sparse-checkout: work with Windows paths
  sparse-checkout: create 'add' subcommand
  sparse-checkout: extract pattern update from 'set' subcommand
  sparse-checkout: extract add_patterns_from_input()
2020-03-05 10:43:02 -08:00
Hariom Verma
4d864895a2 t2402: test worktree path when called in .git directory
The bug which reports an extra `/.git/.` in worktree path when called in
'.git' directory already has been fixed. But unfortunately, the regression
test to ensure this behavior has been forgotten.
Here is that test.

Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Hariom Verma <hariom18599@gmail.com>
Acked-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-04 13:28:00 -08:00
Jeff King
af8ccd8ade remote: drop "explicit" parameter from remote_ref_for_branch()
Commit 9700fae5ee (for-each-ref: let upstream/push report the remote
ref name, 2017-11-07) added a remote_ref_for_branch() helper, which
is modeled after remote_for_branch(). This includes providing an
"explicit" out-parameter that tells the caller whether the remote
was configured by the user, or whether we picked a default name like
"origin".

But unlike remote names, there is no default name when the user
didn't configure one.  The only way the "explicit" parameter is used
by the caller is to use the value returned from the helper when it
is set, and use an empty string otherwise, ignoring the returned
value from the helper.

Let's drop the "explicit" out-parameter, and return NULL when the
returned value from the helper should be ignored, to simplify the
function interface.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Damien Robert <damien.olivier.robert+git@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-03 14:56:05 -08:00
René Scharfe
7655b4119d remote-curl: show progress for fetches over dumb HTTP
Fetching over dumb HTTP transport doesn't show any progress, even with
the option --progress.  If the connection is slow or there is a lot of
data to get then this can take a long time while the user is left to
wonder if git got stuck.

We don't know the number of objects to fetch at the outset, but we can
count the ones we got.  Show an open-ended progress indicator based on
that number if the user asked for it.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-03 13:15:40 -08:00
Junio C Hamano
2f268890c2 The eighth batch for 2.26
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-02 15:07:40 -08:00
Junio C Hamano
aa5a7e02ad Merge branch 'ma/test-cleanup'
Code cleanup.

* ma/test-cleanup:
  t: drop debug `cat` calls
  t9810: drop debug `cat` call
  t4117: check for files using `test_path_is_file`
2020-03-02 15:07:20 -08:00
Junio C Hamano
58595e713c Merge branch 'rs/blame-typefix-for-fingerprint'
Code cleanup.

* rs/blame-typefix-for-fingerprint:
  blame: provide type of fingerprints pointer
2020-03-02 15:07:20 -08:00
Junio C Hamano
ff41848e99 Merge branch 'rs/micro-cleanups'
Code cleanup.

* rs/micro-cleanups:
  use strpbrk(3) to search for characters from a given set
  quote: use isalnum() to check for alphanumeric characters
2020-03-02 15:07:20 -08:00
Junio C Hamano
4cbf1a0e22 Merge branch 'es/worktree-cleanup'
Code cleanup.

* es/worktree-cleanup:
  worktree: drop unused code from get_main_worktree()
2020-03-02 15:07:20 -08:00
Junio C Hamano
46703057c1 Merge branch 'ak/test-log-graph'
Test update.

* ak/test-log-graph:
  lib-log-graph: consolidate colored graph cmp logic
  lib-log-graph: consolidate test_cmp_graph logic
2020-03-02 15:07:19 -08:00
Junio C Hamano
777815f5f9 Merge branch 'jk/run-command-formatfix'
Code style cleanup.

* jk/run-command-formatfix:
  run-command.h: fix mis-indented struct member
2020-03-02 15:07:19 -08:00
Junio C Hamano
444cff61b4 Merge branch 'ds/partial-clone-fixes'
Fix for a bug revealed by a recent change to make the protocol v2
the default.

* ds/partial-clone-fixes:
  partial-clone: avoid fetching when looking for objects
  partial-clone: demonstrate bugs in partial fetch
2020-03-02 15:07:19 -08:00
Junio C Hamano
48d5f25ddd Merge branch 'en/t3433-rebase-stat-dirty-failure'
The merge-recursive machinery failed to refresh the cache entry for
a merge result in a couple of places, resulting in an unnecessary
merge failure, which has been fixed.

* en/t3433-rebase-stat-dirty-failure:
  merge-recursive: fix the refresh logic in update_file_flags
  t3433: new rebase testcase documenting a stat-dirty-like failure
2020-03-02 15:07:19 -08:00
Junio C Hamano
8c22bd9ff9 Merge branch 'en/rebase-backend'
"git rebase" has learned to use the merge backend (i.e. the
machinery that drives "rebase -i") by default, while allowing
"--apply" option to use the "apply" backend (e.g. the moral
equivalent of "format-patch piped to am").  The rebase.backend
configuration variable can be set to customize.

* en/rebase-backend:
  rebase: rename the two primary rebase backends
  rebase: change the default backend from "am" to "merge"
  rebase: make the backend configurable via config setting
  rebase tests: repeat some tests using the merge backend instead of am
  rebase tests: mark tests specific to the am-backend with --am
  rebase: drop '-i' from the reflog for interactive-based rebases
  git-prompt: change the prompt for interactive-based rebases
  rebase: add an --am option
  rebase: move incompatibility checks between backend options a bit earlier
  git-rebase.txt: add more details about behavioral differences of backends
  rebase: allow more types of rebases to fast-forward
  t3432: make these tests work with either am or merge backends
  rebase: fix handling of restrict_revision
  rebase: make sure to pass along the quiet flag to the sequencer
  rebase, sequencer: remove the broken GIT_QUIET handling
  t3406: simplify an already simple test
  rebase (interactive-backend): fix handling of commits that become empty
  rebase (interactive-backend): make --keep-empty the default
  t3404: directly test the behavior of interest
  git-rebase.txt: update description of --allow-empty-message
2020-03-02 15:07:19 -08:00
Junio C Hamano
cb2f5a8e97 Merge branch 'en/check-ignore'
"git check-ignore" did not work when the given path is explicitly
marked as not ignored with a negative entry in the .gitignore file.

* en/check-ignore:
  check-ignore: fix documentation and implementation to match
2020-03-02 15:07:18 -08:00
Junio C Hamano
0df82d99da Merge branch 'jk/object-filter-with-bitmap'
The object reachability bitmap machinery and the partial cloning
machinery were not prepared to work well together, because some
object-filtering criteria that partial clones use inherently rely
on object traversal, but the bitmap machinery is an optimization
to bypass that object traversal.  There however are some cases
where they can work together, and they were taught about them.

* jk/object-filter-with-bitmap:
  rev-list --count: comment on the use of count_right++
  pack-objects: support filters with bitmaps
  pack-bitmap: implement BLOB_LIMIT filtering
  pack-bitmap: implement BLOB_NONE filtering
  bitmap: add bitmap_unset() function
  rev-list: use bitmap filters for traversal
  pack-bitmap: basic noop bitmap filter infrastructure
  rev-list: allow commit-only bitmap traversals
  t5310: factor out bitmap traversal comparison
  rev-list: allow bitmaps when counting objects
  rev-list: make --count work with --objects
  rev-list: factor out bitmap-optimized routines
  pack-bitmap: refuse to do a bitmap traversal with pathspecs
  rev-list: fallback to non-bitmap traversal when filtering
  pack-bitmap: fix leak of haves/wants object lists
  pack-bitmap: factor out type iterator initialization
2020-03-02 15:07:18 -08:00
Junio C Hamano
80648bb3f2 Merge branch 'jk/push-option-doc-markup-fix'
Doc markup fix.

* jk/push-option-doc-markup-fix:
  doc/config/push: use longer "--" line for preformatted example
2020-03-02 15:07:18 -08:00
Junio C Hamano
29b09c518c Merge branch 'jk/doc-diff-parallel'
Update to doc-diff.

* jk/doc-diff-parallel:
  doc-diff: use single-colon rule in rendering Makefile
2020-03-02 15:07:17 -08:00
Harald van Dijk
237a28173f show_one_mergetag: print non-parent in hex form.
When a mergetag names a non-parent, which can occur after a shallow
clone, its hash was previously printed as raw data. Print it in hex form
instead.

Signed-off-by: Harald van Dijk <harald@gigawatt.nl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-02 12:34:00 -08:00
Pratyush Yadav
5eb9397e88 git-gui: fix error popup when doing blame -> "Show History Context"
In d9c6469 (git-gui: update status bar to track operations, 2019-12-01)
the call to 'ui_status' in 'do_gitk' was updated to create the newly
introduced "status bar operation". This allowed this status text to show
along with other operations happening in parallel, and removed a race
between all these operations.

But in that refactor, the fact that 'ui_status' checks for the existence
of 'main_status' was overlooked. This leads to an error message popping
up when the user selects "Show History Context" from the blame window
context menu on a source line. The error occurs because when running
"blame" 'main_status' is not initialized.

So, add a check for the existence of 'main_status' in 'do_gitk'. This
fix reverts to the original behaviour. In the future, we might want to
look into a better way of telling 'do_gitk' which status bar to use.

Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>
2020-03-03 00:06:34 +05:30
Junio C Hamano
0106b1d4be Revert "gpg-interface: prefer check_signature() for GPG verification"
This reverts commit 72b006f4bf, which
breaks the end-user experience when merging a signed tag without
having the public key.  We should report "can't check because we
have no public key", but the code with this change claimed that
there was no signature.
2020-02-28 09:43:17 -08:00
Jeff King
7329d94be7 config.mak.dev: re-enable -Wformat-zero-length
We recently triggered some -Wformat-zero-length warnings in the code,
but no developers noticed because we suppress that warning in builds
with the DEVELOPER=1 Makefile knob set. But we _don't_ suppress them in
a non-developer build (and they're part of -Wall). So even though
non-developers probably aren't using -Werror, they see the annoying
warnings when they build.

We've had back and forth discussion over the years on whether this
warning is useful or not. In most cases we've seen, it's not true that
the call is a mistake, since we're using its side effects (like adding a
newline status_printf_ln()) or writing an empty string to a destination
which is handled by the function (as in write_file()). And so we end up
working around it in the source by passing ("%s", "").

There's more discussion in the subthread starting at:

  https://lore.kernel.org/git/xmqqtwaod7ly.fsf@gitster.mtv.corp.google.com/

The short of it is that we probably can't just disable the warning for
everybody because of portability issues. And ignoring it for developers
puts us in the situation we're in now, where non-dev builds are annoyed.

Since the workaround is both rarely needed and fairly straight-forward,
let's just commit to doing it as necessary, and re-enable the warning.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-28 08:39:45 -08:00
Ralf Thielow
7daf4f2ac7 rebase-interactive.c: silence format-zero-length warnings
Fixes the following warnings:

rebase-interactive.c: In function ‘edit_todo_list’:
rebase-interactive.c:137:38: warning: zero-length gnu_printf format string [-Wformat-zero-length]
    write_file(rebase_path_dropped(), "");
rebase-interactive.c:144:37: warning: zero-length gnu_printf format string [-Wformat-zero-length]
   write_file(rebase_path_dropped(), "");

Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-28 08:39:09 -08:00
Alexandr Miloslavskiy
94f4d01932 mingw: workaround for hangs when sending STDIN
Explanation
-----------
The problem here is flawed `poll()` implementation. When it tries to
see if pipe can be written without blocking, it eventually calls
`NtQueryInformationFile()` and tests `WriteQuotaAvailable`. However,
the meaning of quota was misunderstood. The value of quota is reduced
when either some data was written to a pipe, *or* there is a pending
read on the pipe. Therefore, if there is a pending read of size >= than
the pipe's buffer size, poll() will think that pipe is not writable and
will hang forever, usually that means deadlocking both pipe users.

I have studied the problem and found that Windows pipes track two values:
`QuotaUsed` and `BytesInQueue`. The code in `poll()` apparently wants to
know `BytesInQueue` instead of quota. Unfortunately, `BytesInQueue` can
only be requested from read end of the pipe, while `poll()` receives
write end.

The git's implementation of `poll()` was copied from gnulib, which also
contains a flawed implementation up to today.

I also had a look at implementation in cygwin, which is also broken in a
subtle way. It uses this code in `pipe_data_available()`:
	fpli.WriteQuotaAvailable = (fpli.OutboundQuota - fpli.ReadDataAvailable)
However, `ReadDataAvailable` always returns 0 for the write end of the pipe,
turning the code into an obfuscated version of returning pipe's total
buffer size, which I guess will in turn have `poll()` always say that pipe
is writable. The commit that introduced the code doesn't say anything about
this change, so it could be some debugging code that slipped in.

These are the typical sizes used in git:
0x2000 - default read size in `strbuf_read()`
0x1000 - default read size in CRT, used by `strbuf_getwholeline()`
0x2000 - pipe buffer size in compat\mingw.c

As a consequence, as soon as child process uses `strbuf_read()`,
`poll()` in parent process will hang forever, deadlocking both
processes.

This results in two observable behaviors:
1) If parent process begins sending STDIN quickly (and usually that's
   the case), then first `poll()` will succeed and first block will go
   through. MAX_IO_SIZE_DEFAULT is 8MB, so if STDIN exceeds 8MB, then
   it will deadlock.
2) If parent process waits a little bit for any reason (including OS
   scheduler) and child is first to issue `strbuf_read()`, then it will
   deadlock immediately even on small STDINs.

The problem is illustrated by `git stash push`, which will currently
read the entire patch into memory and then send it to `git apply` via
STDIN. If patch exceeds 8MB, git hangs on Windows.

Possible solutions
------------------
1) Somehow obtain `BytesInQueue` instead of `QuotaUsed`
   I did a pretty thorough search and didn't find any ways to obtain
   the value from write end of the pipe.
2) Also give read end of the pipe to `poll()`
   That can be done, but it will probably invite some dirty code,
   because `poll()`
   * can accept multiple pipes at once
   * can accept things that are not pipes
   * is expected to have a well known signature.
3) Make `poll()` always reply "writable" for write end of the pipe
   Afterall it seems that cygwin (accidentally?) does that for years.
   Also, it should be noted that `pump_io_round()` writes 8MB blocks,
   completely ignoring the fact that pipe's buffer size is only 8KB,
   which means that pipe gets clogged many times during that single
   write. This may invite a deadlock, if child's STDERR/STDOUT gets
   clogged while it's trying to deal with 8MB of STDIN. Such deadlocks
   could be defeated with writing less than pipe's buffer size per
   round, and always reading everything from STDOUT/STDERR before
   starting next round. Therefore, making `poll()` always reply
   "writable" shouldn't cause any new issues or block any future
   solutions.
4) Increase the size of the pipe's buffer
   The difference between `BytesInQueue` and `QuotaUsed` is the size
   of pending reads. Therefore, if buffer is bigger than size of reads,
   `poll()` won't hang so easily. However, I found that for example
   `strbuf_read()` will get more and more hungry as it reads large inputs,
   eventually surpassing any reasonable pipe buffer size.

Chosen solution
---------------
Make `poll()` always reply "writable" for write end of the pipe.
Hopefully one day someone will find a way to implement it properly.

Reproduction
------------
printf "%8388608s" X >large_file.txt
git stash push --include-untracked -- large_file.txt

I have decided not to include this as test to avoid slowing down the
test suite. I don't expect the specific problem to come back, and
chances are that `git stash push` will be reworked to avoid sending the
entire patch via STDIN.

Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-27 14:23:29 -08:00
Junio C Hamano
1ff466c018 Documentation: clarify that -h alone stands for help
We seem to be getting new users who get confused every 20 months or
so with this "-h consistently wants to give help, but the commands
to which `-h` may feel like a good short-form option want it to mean
something else." compromise.

Let's make sure that the readers know that `git cmd -h` (with no
other arguments) is a way to get usage text, even for commands like
ls-remote and grep.

Also extend the description that is already in gitcli.txt, as it is
clear that users still get confused with the current text.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-27 14:14:01 -08:00