Commit Graph

312 Commits

Author SHA1 Message Date
Johannes Schindelin
877da5e208 run-command: declare the git_shell_path() function globally
The intention is to use it in `git var GIT_SHELL_PATH`, therefore we
need this function to stop being file-local only.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-07-13 16:23:37 -07:00
Johannes Schindelin
92fe7c7d42 run-command(win32): resolve the path to the Unix shell early
In 776297548e (Do not use SHELL_PATH from build system in
prepare_shell_cmd on Windows, 2012-04-17), the hard-coded path to the
Unix shell was replaced by passing `sh` instead when executing Unix
shell scripts in Git.

This was done because the hard-coded path to the Unix shell is incorrect
on Windows because it not only is a Unix-style absolute path instead of
a Windows one, but Git uses the runtime prefix feature on Windows, i.e.
the correct path cannot be hard-coded.

Naturally, the `sh` argument will be resolved to the full path of said
executable eventually.

To help fixing the bug where `git var GIT_SHELL_PATH` currently does not
reflect that logic, but shows that incorrect hard-coded Unix-style
absolute path, let's resolve the full path to the `sh` executable early
in the `git_shell_path()` function so that we can use it in `git var`,
too, and be sure that the output is equivalent to what `run_command()`
does when it is asked to execute a command-line using a Unix shell.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-07-13 16:23:37 -07:00
Johannes Schindelin
0593c1ea30 run-command: refactor getting the Unix shell path into its own function
This encapsulates the platform-specific logic better.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-07-13 16:23:36 -07:00
Junio C Hamano
7b472da915 Merge branch 'ps/use-the-repository'
A CPP macro USE_THE_REPOSITORY_VARIABLE is introduced to help
transition the codebase to rely less on the availability of the
singleton the_repository instance.

* ps/use-the-repository:
  hex: guard declarations with `USE_THE_REPOSITORY_VARIABLE`
  t/helper: remove dependency on `the_repository` in "proc-receive"
  t/helper: fix segfault in "oid-array" command without repository
  t/helper: use correct object hash in partial-clone helper
  compat/fsmonitor: fix socket path in networked SHA256 repos
  replace-object: use hash algorithm from passed-in repository
  protocol-caps: use hash algorithm from passed-in repository
  oidset: pass hash algorithm when parsing file
  http-fetch: don't crash when parsing packfile without a repo
  hash-ll: merge with "hash.h"
  refs: avoid include cycle with "repository.h"
  global: introduce `USE_THE_REPOSITORY_VARIABLE` macro
  hash: require hash algorithm in `empty_tree_oid_hex()`
  hash: require hash algorithm in `is_empty_{blob,tree}_oid()`
  hash: make `is_null_oid()` independent of `the_repository`
  hash: convert `oidcmp()` and `oideq()` to compare whole hash
  global: ensure that object IDs are always padded
  hash: require hash algorithm in `oidread()` and `oidclr()`
  hash: require hash algorithm in `hasheq()`, `hashcmp()` and `hashclr()`
  hash: drop (mostly) unused `is_empty_{blob,tree}_sha1()` functions
2024-07-02 09:59:00 -07:00
Junio C Hamano
4216329457 Merge branch 'ps/no-writable-strings'
Building with "-Werror -Wwrite-strings" is now supported.

* ps/no-writable-strings: (27 commits)
  config.mak.dev: enable `-Wwrite-strings` warning
  builtin/merge: always store allocated strings in `pull_twohead`
  builtin/rebase: always store allocated string in `options.strategy`
  builtin/rebase: do not assign default backend to non-constant field
  imap-send: fix leaking memory in `imap_server_conf`
  imap-send: drop global `imap_server_conf` variable
  mailmap: always store allocated strings in mailmap blob
  revision: always store allocated strings in output encoding
  remote-curl: avoid assigning string constant to non-const variable
  send-pack: always allocate receive status
  parse-options: cast long name for OPTION_ALIAS
  http: do not assign string constant to non-const field
  compat/win32: fix const-correctness with string constants
  pretty: add casts for decoration option pointers
  object-file: make `buf` parameter of `index_mem()` a constant
  object-file: mark cached object buffers as const
  ident: add casts for fallback name and GECOS
  entry: refactor how we remove items for delayed checkouts
  line-log: always allocate the output prefix
  line-log: stop assigning string constant to file parent buffer
  ...
2024-06-17 15:55:58 -07:00
Junio C Hamano
cff3b034d5 Merge branch 'jc/varargs-attributes'
Varargs functions that are unannotated as printf-like or execl-like
have been annotated as such.

* jc/varargs-attributes:
  __attribute__: add a few missing format attributes
  __attribute__: mark some functions with LAST_ARG_MUST_BE_NULL
  __attribute__: remove redundant attribute declaration for git_die_config()
  __attribute__: trace2_region_enter_printf() is like "printf"
2024-06-17 15:55:55 -07:00
Patrick Steinhardt
e7da938570 global: introduce USE_THE_REPOSITORY_VARIABLE macro
Use of the `the_repository` variable is deprecated nowadays, and we
slowly but steadily convert the codebase to not use it anymore. Instead,
callers should be passing down the repository to work on via parameters.

It is hard though to prove that a given code unit does not use this
variable anymore. The most trivial case, merely demonstrating that there
is no direct use of `the_repository`, is already a bit of a pain during
code reviews as the reviewer needs to manually verify claims made by the
patch author. The bigger problem though is that we have many interfaces
that implicitly rely on `the_repository`.

Introduce a new `USE_THE_REPOSITORY_VARIABLE` macro that allows code
units to opt into usage of `the_repository`. The intent of this macro is
to demonstrate that a certain code unit does not use this variable
anymore, and to keep it from new dependencies on it in future changes,
be it explicit or implicit

For now, the macro only guards `the_repository` itself as well as
`the_hash_algo`. There are many more known interfaces where we have an
implicit dependency on `the_repository`, but those are not guarded at
the current point in time. Over time though, we should start to add
guards as required (or even better, just remove them).

Define the macro as required in our code units. As expected, most of our
code still relies on the global variable. Nearly all of our builtins
rely on the variable as there is no way yet to pass `the_repository` to
their entry point. For now, declare the macro in "biultin.h" to keep the
required changes at least a little bit more contained.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:33 -07:00
Junio C Hamano
89e78c7cda __attribute__: trace2_region_enter_printf() is like "printf"
The last part of the parameter list the function takes is like
parameters to printf.  Mark it as such.

An existing call that formats a value of type size_t using "%d" was
found by the compiler with the help with this annotation; fix it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-10 09:16:19 -07:00
Patrick Steinhardt
b567004b4b global: improve const correctness when assigning string constants
We're about to enable `-Wwrite-strings`, which changes the type of
string constants to `const char[]`. Fix various sites where we assign
such constants to non-const variables.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-07 10:30:48 -07:00
Ian Wienand
291ef5b61c run-command: show prepared command
This adds a trace point in start_command so we can see the full
command invocation without having to resort to strace/code inspection.
For example:

 $ GIT_TRACE=1 git test foo
 git.c:755               trace: exec: git-test foo
 run-command.c:657       trace: run_command: git-test foo
 run-command.c:657       trace: run_command: 'echo $*' foo
 run-command.c:749       trace: start_command: /bin/sh -c 'echo $* "$@"' 'echo $*' foo

Prior changes have made the documentation around the internals of the
alias command execution clearer, but I have still found this detailed
view of the aliased command being run helpful for debugging purposes.

A test case is added to ensure the full command output is present in
the execution flow.

Signed-off-by: Ian Wienand <iwienand@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-31 15:47:55 -07:00
Patrick Steinhardt
b396ee6bed run-command: introduce function to prepare auto-maintenance process
The `run_auto_maintenance()` function is responsible for spawning a new
`git maintenance run --auto` process. To do so, it sets up the `sturct
child_process` and then runs it by executing `run_command()` directly.
This is rather inflexible in case callers want to modify the child
process somewhat, e.g. to redirect stderr or stdout.

Introduce a new `prepare_auto_maintenance()` function to plug this gap.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-04-17 08:42:26 -07:00
Elijah Newren
eea0e59ffb treewide: remove unnecessary includes in source files
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>
2023-12-26 12:04:31 -08:00
Junio C Hamano
8cdd5e713d Merge branch 'ma/locate-in-path-for-windows'
"git bisect visualize" stopped running "gitk" on Git for Windows
when the command was reimplemented in C around Git 2.34 timeframe.
This has been corrected.

* ma/locate-in-path-for-windows:
  docs: update when `git bisect visualize` uses `gitk`
  compat/mingw: implement a native locate_in_PATH()
  run-command: conditionally define locate_in_PATH()
2023-08-09 16:18:16 -07:00
Matthias Aßhauer
bb532b5345 run-command: conditionally define locate_in_PATH()
This commit doesn't change any behaviour by itself, but allows us to easily
define compat replacements for locate_in_PATH(). It prepares us for the next
commit that adds a native Windows implementation of locate_in_PATH().

Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-08-03 21:21:07 -07:00
Junio C Hamano
a1264a08a1 Merge branch 'en/header-split-cache-h-part-3'
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
  ...
2023-06-29 16:43:21 -07:00
Junio C Hamano
dcedba13b3 Merge branch 'rs/run-command-exec-error-on-noent'
Simplify error message when run-command fails to start a command.

* rs/run-command-exec-error-on-noent:
  run-command: report exec error even on ENOENT
  t1800: loosen matching of error message for bad shebang
2023-06-23 11:21:16 -07:00
Elijah Newren
64c8559575 run-command.h: move declarations for run-command.c from cache.h
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-06-21 13:39:53 -07:00
René Scharfe
6d224ac286 run-command: report exec error even on ENOENT
If execve(2) fails with ENOENT and we report the error, we use the
format "cannot run %s", followed by the actual error message.  For other
errors we use "cannot exec '%s'".

Stop making this subtle distinction and use the second format for all
execve(2) errors.  This simplifies the code and makes the prefix more
precise by indicating the failed operation.  It also allows us to
slightly simplify t1800.16.

On Windows -- which lacks execve(2) -- we already use a single format in
all cases: "cannot spawn %s".

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-06-12 11:00:22 -07:00
Junio C Hamano
75ab1fa5ab Merge branch 'tb/run-command-needs-alloc-h'
Fix the build problem with NO_PTHREADS defined, a fallout from
recent header file shuffling.

* tb/run-command-needs-alloc-h:
  run-command.c: fix missing include under `NO_PTHREADS`
2023-05-19 09:27:06 -07:00
Taylor Blau
52c0f3318d run-command.c: fix missing include under NO_PTHREADS
Git 2.41-rc0 fails to compile run-command.c with `NO_PTHREADS` defined,
i.e.

  $ make NO_PTHREADS=1 run-command.o

as `ALLOC_GROW()` macro is used in the `atexit()` emulation but the
macro definition is not available.

This bisects to 36bf195890 (alloc.h: move ALLOC_GROW() functions from
cache.h, 2023-02-24), which replaced includes of <cache.h> with
<alloc.h>, which is the new home of `ALLOC_GROW()` (and
`ALLOC_GROW_BY()`).

We can see that run-command.c is the only one that try to use these
macros without including <alloc.h>.

  $ git grep -l -e '[^_]ALLOC_GROW(' -e 'ALLOC_GROW_BY(' \*.c | sort >/tmp/1
  $ git grep -l 'alloc\.h' \*.c | sort >/tmp/2
  $ comm -23 /tmp/[12]
  compat/simple-ipc/ipc-unix-socket.c
  run-command.c

The "compat/" file only talks about the macro in the comment,
and is not broken.

We could fix this by conditionally including "alloc.h" when
`NO_PTHREADS` is defined.  But we have relatively few examples of
conditional includes throughout the tree[^1].

Instead, include "alloc.h" unconditionally in run-command.c to allow it
to successfully compile even when NO_PTHREADS is defined.

[^1]: With `git grep -E -A1 '#if(n)?def' -- **/*.c | grep '#include' -B1`.

Reported-by: Randall S. Becker <randall.becker@nexbridge.ca>
Co-authored-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-16 15:17:17 -07:00
Elijah Newren
cb2a51356d symlinks.h: move declarations for symlinks.c functions from cache.h
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24 12:47:31 -07:00
Elijah Newren
74ea5c9574 treewide: be explicit about dependence on trace.h & trace2.h
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>
2023-04-11 08:52:08 -07:00
Elijah Newren
32a8f51061 environment.h: move declarations for environment.c functions from cache.h
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21 10:56:53 -07:00
Elijah Newren
f394e093df treewide: be explicit about dependence on gettext.h
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>
2023-03-21 10:56:51 -07:00
Jeff King
ce41759ed5 run-command: mark error routine parameters as unused
After forking but before exec-ing a command, we install special
error/warn/die handlers in the child. These ignore the error messages
they get, since the idea is that they shouldn't be called in the first
place.

Arguably they could pass along that error message _in addition_ to
saying "error() should not be called in a child", but since the whole
point is to avoid any conflicts on stdio/malloc locks, etc, we're better
to just keep these simple. Seeing them trigger is effectively a bug, and
the developer is probably better off grabbing a stack trace.

But we do want to mark the functions so that -Wunused-parameter doesn't
complain.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-24 09:13:30 -08:00
Emily Shaffer
540267304d run-command: allow stdin for run_processes_parallel
While it makes sense not to inherit stdin from the parent process to
avoid deadlocking, it's not necessary to completely ban stdin to
children. An informed user should be able to configure stdin safely. By
setting `some_child.process.no_stdin=1` before calling `get_next_task()`
we provide a reasonable default behavior but enable users to set up
stdin streaming for themselves during the callback.

`some_child.process.stdout_to_stderr`, however, remains unmodifiable by
`get_next_task()` - the rest of the run_processes_parallel() API depends
on child output in stderr.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-08 12:50:03 -08:00
Ævar Arnfjörð Bjarmason
5123e6e7bd run-command.c: remove dead assignment in while-loop
Remove code that's been unused since it was added in
c553c72eed (run-command: add an asynchronous parallel child
processor, 2015-12-15).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-02-08 12:50:03 -08:00
Andrei Rybak
b39a84185e *: fix typos which duplicate a word
Fix typos in code comments which repeat various words.  Most of the
cases are simple in that they repeat a word that usually cannot be
repeated in a grammatically correct sentence.  Just remove the
incorrectly duplicated word in these cases and rewrap text, if needed.

A tricky case is usage of "that that", which is sometimes grammatically
correct.  However, an instance of this in "t7527-builtin-fsmonitor.sh"
doesn't need two words "that", because there is only one daemon being
discussed, so replace the second "that" with "the".

Reword code comment "entries exist on on-disk index" in function
update_one in file cache-tree.c, by replacing incorrect preposition "on"
with "in".

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-01-08 10:28:34 +09:00
Junio C Hamano
4e09e0dae6 Merge branch 'sx/pthread-error-check-fix'
Correct pthread API usage.

* sx/pthread-error-check-fix:
  maintenance: compare output of pthread functions for inequality with 0
2022-12-19 11:46:17 +09:00
Seija
786e67611d maintenance: compare output of pthread functions for inequality with 0
The documentation for pthread_create and pthread_sigmask state that:

"On success, pthread_create() returns 0;
on error, it returns an error number"

As such, we ought to check for an error
by seeing if the output is not 0.

Checking for "less than" is a mistake
as the error code numbers can be greater than 0.

Signed-off-by: Seija <doremylover123@gmail.com>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-12-05 10:15:54 +09:00
Taylor Blau
be4ac3b197 Merge branch 'rs/no-more-run-command-v'
Simplify the run-command API.

* rs/no-more-run-command-v:
  replace and remove run_command_v_opt()
  replace and remove run_command_v_opt_cd_env_tr2()
  replace and remove run_command_v_opt_tr2()
  replace and remove run_command_v_opt_cd_env()
  use child_process members "args" and "env" directly
  use child_process member "args" instead of string array variable
  sequencer: simplify building argument list in do_exec()
  bisect--helper: factor out do_bisect_run()
  bisect: simplify building "checkout" argument list
  am: simplify building "show" argument list
  run-command: fix return value comment
  merge: remove always-the-same "verbose" arguments
2022-11-08 17:15:12 -05:00
René Scharfe
ddbb47fde9 replace and remove run_command_v_opt()
Replace the remaining calls of run_command_v_opt() with run_command()
calls and explict struct child_process variables.  This is more verbose,
but not by much overall.  The code becomes more flexible, e.g. it's easy
to extend to conditionally add a new argument.

Then remove the now unused function and its own flag names, simplifying
the run-command API.

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 14:04:51 -04:00
René Scharfe
ef249b398e replace and remove run_command_v_opt_cd_env_tr2()
The convenience function run_command_v_opt_cd_env_tr2() has no external
callers left.  Inline it and remove it from the API.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 14:04:50 -04:00
René Scharfe
d82dbbd849 replace and remove run_command_v_opt_tr2()
The convenience function run_command_v_opt_tr2() is only used by a
single caller.  Use struct child_process and run_command() directly
instead and remove the underused function.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 14:04:48 -04:00
René Scharfe
eb5b6b57d0 replace and remove run_command_v_opt_cd_env()
run_command_v_opt_cd_env() is only used in an example in a comment.  Use
the struct child_process member "env" and run_command() directly instead
and then remove the unused convenience function.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-10-30 14:04:47 -04:00
Ævar Arnfjörð Bjarmason
0b0ab95f17 run-command.c: remove "max_processes", add "const" to signal() handler
As with the *_fn members removed in a preceding commit, let's not copy
the "processes" member of the "struct run_process_parallel_opts" over
to the "struct parallel_processes".

In this case we need the number of processes for the kill_children()
function, which will be called from a signal handler. To do that
adjust this code added in c553c72eed (run-command: add an
asynchronous parallel child processor, 2015-12-15) so that we use a
dedicated "struct parallel_processes_for_signal" for passing data to
the signal handler, in addition to the "struct parallel_process" it'll
now have access to our "opts" variable.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:42 -07:00
Ævar Arnfjörð Bjarmason
d1610eef3f run-command.c: pass "opts" further down, and use "opts->processes"
Continue the migration away from the "max_processes" member of "struct
parallel_processes" to the "processes" member of the "struct
run_process_parallel_opts", in this case we needed to pass the "opts"
further down into pp_cleanup() and pp_buffer_stderr().

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:42 -07:00
Ævar Arnfjörð Bjarmason
9f3df6c048 run-command.c: use "opts->processes", not "pp->max_processes"
Neither the "processes" nor "max_processes" members ever change after
their initialization, and they're always equivalent, but some existing
code used "pp->max_processes" when we were already passing the "opts"
to the function, let's use the "opts" directly instead.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:42 -07:00
Ævar Arnfjörð Bjarmason
2aa8d2259f run-command.c: don't copy "data" to "struct parallel_processes"
As with the *_fn members removed in a preceding commit, let's not copy
the "data" member of the "struct run_process_parallel_opts" over to
the "struct parallel_processes". Now that we're passing the "opts"
down there's no reason to do so.

This makes the code easier to follow, as we have a "const" attribute
on the "struct run_process_parallel_opts", but not "struct
parallel_processes". We do not alter the "ungroup" argument, so
storing it in the non-const structure would make this control flow
less obvious.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:42 -07:00
Ævar Arnfjörð Bjarmason
357f8e6e18 run-command.c: don't copy "ungroup" to "struct parallel_processes"
As with the *_fn members removed in the preceding commit, let's not
copy the "ungroup" member of the "struct run_process_parallel_opts"
over to the "struct parallel_processes". Now that we're passing the
"opts" down there's no reason to do so.

This makes the code easier to follow, as we have a "const" attribute
on the "struct run_process_parallel_opts", but not "struct
parallel_processes". We do not alter the "ungroup" argument, so
storing it in the non-const structure would make this control flow
less obvious.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
fa93951d79 run-command.c: don't copy *_fn to "struct parallel_processes"
The only remaining reason for copying the callbacks in the "struct
run_process_parallel_opts" over to the "struct parallel_processes" was
to avoid two if/else statements in case the "start_failure" and
"task_finished" callbacks were NULL.

Let's handle those cases in pp_start_one() and pp_collect_finished()
instead, and avoid the default_* stub functions, and the need to copy
this data around.

Organizing the code like this made more sense before the "struct
run_parallel_parallel_opts" existed, as we'd have needed to pass each
of these as a separate parameter.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
e39c9de860 run-command.c: make "struct parallel_processes" const if possible
Add a "const" to two "struct parallel_processes" parameters where
we're not modifying anything in "pp". For kill_children() we'll call
it from both the signal handler, and from run_processes_parallel()
itself. Adding a "const" there makes it clear that we don't need to
modify any state when killing our children.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
36d69bf77e run-command API: move *_tr2() users to "run_processes_parallel()"
Have the users of the "run_processes_parallel_tr2()" function use
"run_processes_parallel()" instead. In preceding commits the latter
was refactored to take a "struct run_process_parallel_opts" argument,
since the only reason for "run_processes_parallel_tr2()" to exist was
to take arguments that are now a part of that struct we can do away
with it.

See ee4512ed48 (trace2: create new combined trace facility,
2019-02-22) for the addition of the "*_tr2()" variant of the function,
it was used by every caller except "t/helper/test-run-command.c"..

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
6e5ba0bae4 run-command API: have run_process_parallel() take an "opts" struct
As noted in fd3aaf53f7 (run-command: add an "ungroup" option to
run_process_parallel(), 2022-06-07) which added the "ungroup" passing
it to "run_process_parallel()" via the global
"run_processes_parallel_ungroup" variable was a compromise to get the
smallest possible regression fix for "maint" at the time.

This follow-up to that is a start at passing that parameter and others
via a new "struct run_process_parallel_opts", as the earlier
version[1] of what became fd3aaf53f7 did.

Since we need to change all of the occurrences of "n" to
"opt->SOMETHING" let's take the opportunity and rename the terse "n"
to "processes". We could also have picked "max_processes", "jobs",
"threads" etc., but as the API is named "run_processes_parallel()"
let's go with "processes".

Since the new "run_processes_parallel()" function is able to take an
optional "tr2_category" and "tr2_label" via the struct we can at this
point migrate all of the users of "run_processes_parallel_tr2()" over
to it.

But let's not migrate all the API users yet, only the two users that
passed the "ungroup" parameter via the
"run_processes_parallel_ungroup" global

1. https://lore.kernel.org/git/cover-v2-0.8-00000000000-20220518T195858Z-avarab@gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
c333e6f3a8 run-command.c: use designated init for pp_init(), add "const"
Use a designated initializer to initialize those parts of pp_init()
that don't need any conditionals for their initialization, this sets
us on a path to pp_init() itself into mostly a validation and
allocation function.

Since we're doing that we can add "const" to some of the members of
the "struct parallel_processes", which helps to clarify and
self-document this code. E.g. we never alter the "data" pointer we
pass t user callbacks, nor (after the preceding change to stop
invoking online_cpus()) do we change "max_processes", the same goes
for the "ungroup" option.

We can also do away with a call to strbuf_init() in favor of macro
initialization, and to rely on other fields being NULL'd or zero'd.

Making members of a struct "const" rather that the pointer to the
struct itself is usually painful, as e.g. it precludes us from
incrementally setting up the structure. In this case we only set it up
with the assignment in run_process_parallel() and pp_init(), and don't
pass the struct pointer around as "const", so making individual
members "const" is worth the potential hassle for extra safety.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
51243f9f0f run-command API: don't fall back on online_cpus()
When a "jobs = 0" is passed let's BUG() out rather than fall back on
online_cpus(). The default behavior was added when this API was
implemented in c553c72eed (run-command: add an asynchronous parallel
child processor, 2015-12-15).

Most of our code in-tree that scales up to "online_cpus()" by default
calls that function by itself. Keeping this default behavior just for
the sake of two callers means that we'd need to maintain this one spot
where we're second-guessing the config passed down into pp_init().

The preceding commit has an overview of the API callers that passed
"jobs = 0". There were only two of them (actually three, but they
resolved to these two config parsing codepaths).

The "fetch.parallel" caller already had a test for the
"fetch.parallel=0" case added in 0353c68818 (fetch: do not run a
redundant fetch from submodule, 2022-05-16), but there was no such
test for "submodule.fetchJobs". Let's add one here.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:41 -07:00
Ævar Arnfjörð Bjarmason
6a48b428b4 run-command API: make "n" parameter a "size_t"
Make the "n" variable added in c553c72eed (run-command: add an
asynchronous parallel child processor, 2015-12-15) a "size_t". As
we'll see in a subsequent commit we do pass "0" here, but never "jobs
< 0".

We could have made it an "unsigned int", but as we're having to change
this let's not leave another case in the codebase where a size_t and
"unsigned int" size differ on some platforms. In this case it's likely
to never matter, but it's easier to not need to worry about it.

After this and preceding changes:

	make run-command.o DEVOPTS=extra-all CFLAGS=-Wno-unused-parameter

Only has one (and new) -Wsigned-compare warning relevant to a
comparison about our "n" or "{nr,max}_processes": About using our
"n" (size_t) in the same expression as online_cpus() (int). A
subsequent commit will adjust & deal with online_cpus() and that
warning.

The only users of the "n" parameter are:

 * builtin/fetch.c: defaults to 1, reads from the "fetch.parallel"
   config. As seen in the code that parses the config added in
   d54dea77db (fetch: let --jobs=<n> parallelize --multiple, too,
   2019-10-05) will die if the git_config_int() return value is < 0.

   It will however pass us n = 0, as we'll see in a subsequent commit.

 * submodule.c: defaults to 1, reads from "submodule.fetchJobs"
   config. Read via code originally added in a028a1930c (fetching
   submodules: respect `submodule.fetchJobs` config option, 2016-02-29).

   It now piggy-backs on the the submodule.fetchJobs code and
   validation added in f20e7c1ea2 (submodule: remove
   submodule.fetchjobs from submodule-config parsing, 2017-08-02).

   Like builtin/fetch.c it will die if the git_config_int() return
   value is < 0, but like builtin/fetch.c it will pass us n = 0.

 * builtin/submodule--helper.c: defaults to 1. Read via code
   originally added in 2335b870fa (submodule update: expose parallelism
   to the user, 2016-02-29).

   Since f20e7c1ea2 (submodule: remove submodule.fetchjobs from
   submodule-config parsing, 2017-08-02) it shares a config parser and
   semantics with the submodule.c caller.

 * hook.c: hardcoded to 1, see 96e7225b31 (hook: add 'run'
   subcommand, 2021-12-22).

 * t/helper/test-run-command.c: can be -1 after parsing the arguments,
   but will then be overridden to online_cpus() before passing it to
   this API. See be5d88e112 (test-tool run-command: learn to run (parts
   of) the testsuite, 2019-10-04).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:40 -07:00
Ævar Arnfjörð Bjarmason
7dd5762d9f run-command API: have "run_processes_parallel{,_tr2}()" return void
Change the "run_processes_parallel{,_tr2}()" functions to return void,
instead of int. Ever since c553c72eed (run-command: add an
asynchronous parallel child processor, 2015-12-15) they have
unconditionally returned 0.

To get a "real" return value out of this function the caller needs to
get it via the "task_finished_fn" callback, see the example in hook.c
added in 96e7225b31 (hook: add 'run' subcommand, 2021-12-22).

So the "result = " and "if (!result)" code added to "builtin/fetch.c"
d54dea77db (fetch: let --jobs=<n> parallelize --multiple, too,
2019-10-05) has always been redundant, we always took that "if"
path. Likewise the "ret =" in "t/helper/test-run-command.c" added in
be5d88e112 (test-tool run-command: learn to run (parts of) the
testsuite, 2019-10-04) wasn't used, instead we got the return value
from the "if (suite.failed.nr > 0)" block seen in the context.

Subsequent commits will alter this API interface, getting rid of this
always-zero return value makes it easier to understand those changes.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-10-12 14:12:40 -07:00
Jeff King
716c1f649e pipe_command(): mark stdin descriptor as non-blocking
Our pipe_command() helper lets you both write to and read from a child
process on its stdin/stdout. It's supposed to work without deadlocks
because we use poll() to check when descriptors are ready for reading or
writing. But there's a bug: if both the data to be written and the data
to be read back exceed the pipe buffer, we'll deadlock.

The issue is that the code assumes that if you have, say, a 2MB buffer
to write and poll() tells you that the pipe descriptor is ready for
writing, that calling:

  write(cmd->in, buf, 2*1024*1024);

will do a partial write, filling the pipe buffer and then returning what
it did write. And that is what it would do on a socket, but not for a
pipe. When writing to a pipe, at least on Linux, it will block waiting
for the child process to read() more. And now we have a potential
deadlock, because the child may be writing back to us, waiting for us to
read() ourselves.

An easy way to trigger this is:

  git -c add.interactive.useBuiltin=true \
      -c interactive.diffFilter=cat \
      checkout -p HEAD~200

The diff against HEAD~200 will be big, and the filter wants to write all
of it back to us (obviously this is a dummy filter, but in the real
world something like diff-highlight would similarly stream back a big
output).

If you set add.interactive.useBuiltin to false, the problem goes away,
because now we're not using pipe_command() anymore (instead, that part
happens in perl). But this isn't a bug in the interactive code at all.
It's the underlying pipe_command() code which is broken, and has been
all along.

We presumably didn't notice because most calls only do input _or_
output, not both. And the few that do both, like gpg calls, may have
large inputs or outputs, but never both at the same time (e.g., consider
signing, which has a large payload but a small signature comes back).

The obvious fix is to put the descriptor into non-blocking mode, and
indeed, that makes the problem go away. Callers shouldn't need to
care, because they never see the descriptor (they hand us a buffer to
feed into it).

The included test fails reliably on Linux without this patch. Curiously,
it doesn't fail in our Windows CI environment, but has been reported to
do so for individual developers. It should pass in any environment after
this patch (courtesy of the compat/ layers added in the last few
commits).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-17 09:21:41 -07:00
Jeff King
c6d3cce6f3 pipe_command(): handle ENOSPC when writing to a pipe
When write() to a non-blocking pipe fails because the buffer is full,
POSIX says we should see EAGAIN. But our mingw_write() compat layer on
Windows actually returns ENOSPC for this case. This is probably
something we want to correct, but given that we don't plan to use
non-blocking descriptors in a lot of places, we can work around it by
just catching ENOSPC alongside EAGAIN. If we ever do fix mingw_write(),
then this patch can be reverted.

We don't actually use a non-blocking pipe yet, so this is still just
preparation.

Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-17 09:21:41 -07:00