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67869 commits

Author SHA1 Message Date
Victoria Dye 8e2841890a scalar: update technical doc roadmap with FSMonitor support
Update the Scalar roadmap to reflect completion of enabling the built-in
FSMonitor in Scalar.

Note that implementation of 'scalar help' was moved to the final set of
changes to move Scalar out of 'contrib/'. This is due to a dependency on
changes to 'git help', as all changes to the main Git tree *exclusively*
implemented to support Scalar are part of that series.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Johannes Schindelin ec4c23116b scalar unregister: stop FSMonitor daemon
Especially on Windows, we will need to stop that daemon, just in case
that the directory needs to be removed (the daemon would otherwise hold
a handle to that directory, preventing it from being deleted).

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Matthew John Cheetham 3f1917dc60 scalar: enable built-in FSMonitor on register
Using the built-in FSMonitor makes many common commands quite a bit
faster. So let's teach the `scalar register` command to enable the
built-in FSMonitor and kick-start the fsmonitor--daemon process (for
convenience).

For simplicity, we only support the built-in FSMonitor (and no external
file system monitor such as e.g. Watchman).

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Victoria Dye d934a11c71 scalar: move config setting logic into its own function
Create function 'set_scalar_config()' to contain the logic used in setting
Scalar-defined Git config settings, including how to handle reconfiguring &
overwriting existing values. This function allows future patches to set
config values in parts of 'scalar.c' other than 'set_recommended_config()'.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Victoria Dye 9b24bb9205 scalar-delete: do not 'die()' in 'delete_enlistment()'
Rather than exiting with 'die()' when 'delete_enlistment()' encounters an
error, return an error code with the appropriate message. There's no need
for an abrupt exit with 'die()' in 'delete_enlistment()' because its only
caller ('cmd_delete()') properly cleans up allocated resources and returns
the 'delete_enlistment()' return value as its own exit code.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Victoria Dye d2a79bc953 scalar-[un]register: clearly indicate source of error
When a step in 'register_dir()' or 'unregister_dir()' fails, indicate which
step failed with an error message, rather than silently assigning a nonzero
return code.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:32 -07:00
Victoria Dye adedcee811 scalar-unregister: handle error codes greater than 0
When 'scalar unregister' tries to disable maintenance and remove an
enlistment, ensure that the return value is nonzero if either operation
produces *any* nonzero return value, not just when they return a value less
than 0.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:31 -07:00
Victoria Dye 65f6a9eb0b scalar: constrain enlistment search
Make the search for repository and enlistment root in
'setup_enlistment_directory()' more constrained to simplify behavior and
adhere to 'GIT_CEILING_DIRECTORIES'.

Previously, 'setup_enlistment_directory()' would check whether the provided
path (or current working directory) '<dir>' or its subdirectory '<dir>/src'
was a repository root. If not, the process would repeat on the parent of
'<dir>' until the repository was found or it reached the root of the
filesystem. This meant that a user could specify a path *anywhere* inside an
enlistment (including paths not in the repository contained within the
enlistment) and it would be found.

The downside to this process is that the search would not account for
'GIT_CEILING_DIRECTORIES', so the upward search could result in modifying
repository contents past 'GIT_CEILING_DIRECTORIES'. Similarly, operations
like 'scalar delete' could end up unintentionally deleting the parent of a
repo if its root was named 'src'.

To make this 'setup_enlistment_directory()' both adhere to
'GIT_CEILING_DIRECTORIES' and avoid unwanted deletions, the search for an
enlistment directory is simplified to:

- if '<dir>/src' is a repository root, '<dir>' is the enlistment root
- if '<dir>' is either the repository root or contained within a repository,
  the repository root is the enlistment root

Now, only 'setup_git_directory()' (called by 'setup_enlistment_directory()')
searches upwards from the 'scalar' specified path, enforcing
'GIT_CEILING_DIRECTORIES' in the process. Additionally, 'scalar delete
<dir>/src' will not delete '<dir>' (if users would like to delete it, they
can still specify the enlistment root with 'scalar delete <dir>'). This is
true of any 'scalar' operation; users can invoke 'scalar' on the enlistment
root, but paths must otherwise be inside the repository to be valid.

To help clarify the updated behavior, new tests are added to
't9099-scalar.sh'.

Finally, this change leaves 'strbuf_parent_directory()' with only a single,
WIN32-specific caller in 'delete_enlistment()'. Rather than wrap
'strbuf_parent_directory()' in '#ifdef WIN32' to avoid the "unused function"
compiler error, move the contents of 'strbuf_parent_directory()' into
'delete_enlistment()' and remove the function.

Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 21:35:31 -07:00
Junio C Hamano 795ea8776b The fourteenth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 13:07:05 -07:00
Junio C Hamano fddd8b4801 Merge branch 'll/disk-usage-humanise'
"git rev-list --disk-usage" learned to take an optional value
"human" to show the reported value in human-readable format, like
"3.40MiB".

* ll/disk-usage-humanise:
  rev-list: support human-readable output for `--disk-usage`
2022-08-18 13:07:05 -07:00
Junio C Hamano 9b9445cfde Merge branch 'sy/sparse-rm'
"git rm" has become more aware of the sparse-index feature.

* sy/sparse-rm:
  rm: integrate with sparse-index
  rm: expand the index only when necessary
  pathspec.h: move pathspec_needs_expanded_index() from reset.c to here
  t1092: add tests for `git-rm`
2022-08-18 13:07:05 -07:00
Junio C Hamano 80ffc849bd Merge branch 'vd/sparse-reset-checkout-fixes'
Fixes to sparse index compatibility work for "reset" and "checkout"
commands.

* vd/sparse-reset-checkout-fixes:
  unpack-trees: unpack new trees as sparse directories
  cache.h: create 'index_name_pos_sparse()'
  oneway_diff: handle removed sparse directories
  checkout: fix nested sparse directory diff in sparse index
2022-08-18 13:07:04 -07:00
Junio C Hamano 0d133a3dcf Merge branch 'ds/bundle-uri-more'
The "bundle URI" design gets documented.

* ds/bundle-uri-more:
  bundle-uri: add example bundle organization
  docs: document bundle URI standard
2022-08-18 13:07:04 -07:00
Junio C Hamano 363a193c3a Merge branch 'jk/fsck-tree-mode-bits-fix'
"git fsck" reads mode from tree objects but canonicalizes the mode
before passing it to the logic to check object sanity, which has
hid broken tree objects from the checking logic.  This has been
corrected, but to help exiting projects with broken tree objects
that they cannot fix retroactively, the severity of anomalies this
code detects has been demoted to "info" for now.

* jk/fsck-tree-mode-bits-fix:
  fsck: downgrade tree badFilemode to "info"
  fsck: actually detect bad file modes in trees
  tree-walk: add a mechanism for getting non-canonicalized modes
2022-08-18 13:07:04 -07:00
Junio C Hamano 4d8074bf8e Merge branch 'fc/vimdiff-layout-vimdiff3-fix'
"vimdiff3" regression fix.

* fc/vimdiff-layout-vimdiff3-fix:
  mergetools: vimdiff: simplify tabfirst
  mergetools: vimdiff: fix single window layouts
  mergetools: vimdiff: rework tab logic
  mergetools: vimdiff: fix for diffopt
  mergetools: vimdiff: silence annoying messages
  mergetools: vimdiff: make vimdiff3 actually work
  mergetools: vimdiff: fix comment
2022-08-18 13:07:04 -07:00
Junio C Hamano 58ded4a4dc Merge branch 'po/doc-add-renormalize'
Documentation for "git add --renormalize" has been improved.

* po/doc-add-renormalize:
  doc add: renormalize is not idempotent for CRCRLF
2022-08-18 13:07:03 -07:00
Elijah Newren 565577ed88 merge-ort: provide helpful submodule update message when possible
In commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04), a more detailed message was provided when submodules
conflict, in order to help users know how to resolve those conflicts.
There were a couple situations for which a different message would be
more appropriate, but that commit left handling those for future work.
Unfortunately, that commit would check if any submodules were of the
type that it didn't know how to explain, and, if so, would avoid
providing the more detailed explanation even for the submodules it did
know how to explain.

Change this to have the code print the helpful messages for the subset
of submodules it knows how to explain.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 09:49:30 -07:00
Elijah Newren 34ce504a33 merge-ort: avoid surprise with new sub_flag variable
Commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04) added a sub_flag variable that is used to store a value from
enum conflict_and_info_types, but initializes it with a value of -1 that
does not correspond to any of the conflict_and_info_types.  The code may
never set it to a valid value and yet still use it, which can be
surprising when reading over the code at first.  Initialize it instead
to the generic CONFLICT_SUBMODULE_FAILED_TO_MERGE value, which is still
distinct from the two values we need to special case.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 09:49:30 -07:00
Elijah Newren a5834b775b merge-ort: remove translator lego in new "submodule conflict suggestion"
In commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04), the new "submodule conflict suggestion" code was
translating 6 different pieces of the new message and then used
carefully crafted logic to allow stitching it back together with special
formatting.  Keep the components of the message together as much as
possible, so that:
  * we reduce the number of things translators have to translate
  * translators have more control over the format of the output
  * the code is much easier for developers to understand too

Also, reformat some comments running beyond the 80th column while at it.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-18 09:49:30 -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
Jeff King 14eab817e4 pipe_command(): avoid xwrite() for writing to pipe
If xwrite() sees an EAGAIN response, it will loop forever until the
write succeeds (or encounters a real error). This is due to ef1cf0167a
(xwrite: poll on non-blocking FDs, 2016-06-26), with the idea that we
won't be surprised by a descriptor unexpectedly set as non-blocking.

But that will make things awkward when we do want a non-blocking
descriptor, and a future patch will switch pipe_command() to using one.
In that case, looping on EAGAIN is bad, because the process on the other
end of the pipe may be waiting on us before doing another read() on the
pipe, which would mean we deadlock.

In practice we're not supposed to ever see EAGAIN here, since poll()
will have just told us the descriptor is ready for writing. But our
Windows emulation of poll() will always return "ready" for writing to a
pipe descriptor! This is due to 94f4d01932 (mingw: workaround for hangs
when sending STDIN, 2020-02-17).

Our best bet in that case is to keep handling other descriptors, as any
read() we do may allow the child command to make forward progress (i.e.,
its write() finishes, and then it read()s from its stdin, freeing up
space in the pipe buffer). This means we might busy-loop between poll()
and write() on Windows if the child command is slow to read our input,
but it's much better than the alternative of deadlocking.

In practice, this busy-looping should be rare:

  - for small inputs, we'll just write the whole thing in a single
    write() anyway, non-blocking or not

  - for larger inputs where the child reads input and then processes it
    before writing (e.g., gpg verifying a signature), we may make a few
    extra write() calls that get EAGAIN during the initial write, but
    once it has taken in the whole input, we'll correctly block waiting
    to read back the data.

  - for larger inputs where the child process is streaming output back
    (like a diff filter), we'll likewise see some extra EAGAINs, but
    most of them will be followed immediately by a read(), which will
    let the child command make forward progress.

Of course it won't happen at all for now, since we don't yet use a
non-blocking pipe. This is just preparation for when we do.

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 09:21:40 -07:00
Jeff King ec4f39b233 git-compat-util: make MAX_IO_SIZE define globally available
We define MAX_IO_SIZE within wrapper.c, but it's useful for any code
that wants to do a raw write() for whatever reason (say, because they
want different EAGAIN handling). Let's make it available everywhere.

The alternative would be adding xwrite_foo() variants to give callers
more options. But there's really no reason MAX_IO_SIZE needs to be
abstracted away, so this give callers the most flexibility.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-17 09:21:40 -07:00
René Scharfe 24b56ae4ae nonblock: support Windows
Implement enable_pipe_nonblock() using the Windows API. This works only
for pipes, but that is sufficient for this limited interface. Despite
the API calls used, it handles both "named" and anonymous pipes from our
pipe() emulation.

Signed-off-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 09:21:40 -07:00
Jeff King 10f743389c compat: add function to enable nonblocking pipes
We'd like to be able to make some of our pipes nonblocking so that
poll() can be used effectively, but O_NONBLOCK isn't portable. Let's
introduce a compat wrapper so this can be abstracted for each platform.

The interface is as narrow as possible to let platforms do what's
natural there (rather than having to implement fcntl() and a fake
O_NONBLOCK for example, or having to handle other types of descriptors).

The next commit will add Windows support, at which point we should be
covering all platforms in practice. But if we do find some other
platform without O_NONBLOCK, we'll return ENOSYS. Arguably we could just
trigger a build-time #error in this case, which would catch the problem
earlier. But since we're not planning to use this compat wrapper in many
code paths, a seldom-seen runtime error may be friendlier for such a
platform than blocking compilation completely. Our test suite would
still notice it.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-17 09:21:40 -07:00
Josh Steadmon a29263cf5f fetch-pack: add tracing for negotiation rounds
Currently, negotiation for V0/V1/V2 fetch have trace2 regions covering
the entire negotiation process. However, we'd like additional data, such
as timing for each round of negotiation or the number of "haves" in each
round. Additionally, "independent negotiation" (AKA push negotiation)
has no tracing at all. Having this data would allow us to compare the
performance of the various negotation implementations, and to debug
unexpectedly slow fetch & push sessions.

Add per-round trace2 regions for all negotiation implementations (V0+V1,
V2, and independent negotiation), as well as an overall region for
independent negotiation. Add trace2 data logging for the number of haves
and "in vain" objects for each round, and for the total number of rounds
once negotiation completes.  Finally, add a few checks into various
tests to verify that the number of rounds is logged as expected.

Signed-off-by: Josh Steadmon <steadmon@google.com>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-15 09:17:03 -07:00
Junio C Hamano 9bf691b78c The thirteenth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-14 23:19:28 -07:00
Junio C Hamano 7fac7b563b Merge branch 'js/safe-directory-plus'
Platform-specific code that determines if a directory is OK to use
as a repository has been taught to report more details, especially
on Windows.

* js/safe-directory-plus:
  mingw: handle a file owned by the Administrators group correctly
  mingw: be more informative when ownership check fails on FAT32
  mingw: provide details about unsafe directories' ownership
  setup: prepare for more detailed "dubious ownership" messages
  setup: fix some formatting
2022-08-14 23:19:28 -07:00
Junio C Hamano 7d0a1c8895 Merge branch 'pw/use-glibc-tunable-for-malloc-optim'
Avoid repeatedly running getconf to ask libc version in the test
suite, and instead just as it once per script.

* pw/use-glibc-tunable-for-malloc-optim:
  tests: cache glibc version check
2022-08-14 23:19:28 -07:00
Junio C Hamano c0f6dd49f1 Merge branch 'ab/tech-docs-to-help'
Expose a lot of "tech docs" via "git help" interface.

* ab/tech-docs-to-help:
  docs: move http-protocol docs to man section 5
  docs: move cruft pack docs to gitformat-pack
  docs: move pack format docs to man section 5
  docs: move signature docs to man section 5
  docs: move index format docs to man section 5
  docs: move protocol-related docs to man section 5
  docs: move commit-graph format docs to man section 5
  git docs: add a category for file formats, protocols and interfaces
  git docs: add a category for user-facing file, repo and command UX
  git help doc: use "<doc>" instead of "<guide>"
  help.c: remove common category behavior from drop_prefix() behavior
  help.c: refactor drop_prefix() to use a "switch" statement"
2022-08-14 23:19:28 -07:00
Junio C Hamano 3adacc2817 Merge branch 'jc/rerere-autoupdate-doc'
Update documentation on the "--[no-]rerere-autoupdate" option.

* jc/rerere-autoupdate-doc:
  doc: clarify rerere-autoupdate
  doc: consolidate --rerere-autoupdate description
2022-08-14 23:19:27 -07:00
Junio C Hamano d86ac14dd7 Merge branch 'ab/hooks-regression-fix'
A follow-up fix to a fix for a regression in 2.36.

* ab/hooks-regression-fix:
  hook API: don't segfault on strbuf_addf() to NULL "out"
2022-08-14 23:19:27 -07:00
Matheus Tavares 4d1d843be7 tests: use the new C rot13-filter helper to avoid PERL prereq
The previous commit implemented a C version of the t0021/rot13-filter.pl
script. Let's use this new C helper to eliminate the PERL prereq from
various tests, and also remove the superseded Perl script.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-14 22:57:12 -07:00
Matheus Tavares 52917a998e t0021: implementation the rot13-filter.pl script in C
This script is currently used by three test files: t0021-conversion.sh,
t2080-parallel-checkout-basics.sh, and
t2082-parallel-checkout-attributes.sh. To avoid the need for the PERL
dependency at these tests, let's convert the script to a C test-tool
command. The following commit will take care of actually modifying the
said tests to use the new C helper and removing the Perl script.

The Perl script flushes the log file handler after each write. As
commented in [1], this seems to be an early design decision that was
later reconsidered, but possibly ended up being left in the code by
accident:

	>> +$debug->flush();
	>
	> Isn't $debug flushed automatically?

	Maybe, but autoflush is not explicitly enabled. I will
	enable it again (I disabled it because of Eric's comment
	but I re-read the comment and he is only talking about
	pipes).

Anyways, this behavior is not really needed for the tests and the
flush() calls make the code slightly larger, so let's avoid them
altogether in the new C version.

[1]: https://lore.kernel.org/git/7F1F1A0E-8FC3-4FBD-81AA-37786DE0EF50@gmail.com/

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-14 22:57:12 -07:00
Matheus Tavares bed8947751 t0021: avoid grepping for a Perl-specific string at filter output
This test sets the t0021/rot13-filter.pl script as a long-running
process filter for a git checkout command. It then expects the filter to
fail producing a specific error message at stderr. In the following
commits we are going to replace the script with a C test-tool helper,
but the test currently expects the error message in a Perl-specific
format. That is, when you call `die <msg>` in Perl, it emits
"<msg> at - line 1." In preparation for the conversion, let's avoid the
Perl-specific part and only grep for <msg> itself.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-14 22:57:11 -07:00
Jeff King 1490d7d82d is_promisor_object(): fix use-after-free of tree buffer
Since commit fcc07e980b (is_promisor_object(): free tree buffer after
parsing, 2021-04-13), we'll always free the buffers attached to a
"struct tree" after searching them for promisor links. But there's an
important case where we don't want to do so: if somebody else is already
using the tree!

This can happen during a "rev-list --missing=allow-promisor" traversal
in a partial clone that is missing one or more trees or blobs. The
backtrace for the free looks like this:

      #1 free_tree_buffer tree.c:147
      #2 add_promisor_object packfile.c:2250
      #3 for_each_object_in_pack packfile.c:2190
      #4 for_each_packed_object packfile.c:2215
      #5 is_promisor_object packfile.c:2272
      #6 finish_object__ma builtin/rev-list.c:245
      #7 finish_object builtin/rev-list.c:261
      #8 show_object builtin/rev-list.c:274
      #9 process_blob list-objects.c:63
      #10 process_tree_contents list-objects.c:145
      #11 process_tree list-objects.c:201
      #12 traverse_trees_and_blobs list-objects.c:344
      [...]

We're in the middle of walking through the entries of a tree object via
process_tree_contents(). We see a blob (or it could even be another tree
entry) that we don't have, so we call is_promisor_object() to check it.
That function loops over all of the objects in the promisor packfile,
including the tree we're currently walking. When we're done with it
there, we free the tree buffer. But as we return to the walk in
process_tree_contents(), it's still holding on to a pointer to that
buffer, via its tree_desc iterator, and it accesses the freed memory.

Even a trivial use of "--missing=allow-promisor" triggers this problem,
as the included test demonstrates (it's just a vanilla --blob:none
clone).

We can detect this case by only freeing the tree buffer if it was
allocated on our behalf. This is a little tricky since that happens
inside parse_object(), and it doesn't tell us whether the object was
already parsed, or whether it allocated the buffer itself. But by
checking for an already-parsed tree beforehand, we can distinguish the
two cases.

That feels a little hacky, and does incur an extra lookup in the
object-hash table. But that cost is fairly minimal compared to actually
loading objects (and since we're iterating the whole pack here, we're
likely to be loading most objects, rather than reusing cached results).

It may also be a good direction for this function in general, as there
are other possible optimizations that rely on doing some analysis before
parsing:

  - we could detect blobs and avoid reading their contents; they can't
    link to other objects, but parse_object() doesn't know that we don't
    care about checking their hashes.

  - we could avoid allocating object structs entirely for most objects
    (since we really only need them in the oidset), which would save
    some memory.

  - promisor commits could use the commit-graph rather than loading the
    object from disk

This commit doesn't do any of those optimizations, but I think it argues
that this direction is reasonable, rather than relying on parse_object()
and trying to teach it to give us more information about whether it
parsed.

The included test fails reliably under SANITIZE=address just when
running "rev-list --missing=allow-promisor". Checking the output isn't
strictly necessary to detect the bug, but it seems like a reasonable
addition given the general lack of coverage for "allow-promisor" in the
test suite.

Reported-by: Andrew Olsen <andrew.olsen@koordinates.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-14 18:03:36 -07:00
Victoria Dye 43370b1e91 scalar: update technical doc roadmap
Update the Scalar roadmap to reflect the completion of generalizing 'scalar
diagnose' into 'git diagnose' and 'git bugreport --diagnose'.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:03 -07:00
Victoria Dye 672196a307 scalar-diagnose: use 'git diagnose --mode=all'
Replace implementation of 'scalar diagnose' with an internal invocation of
'git diagnose --mode=all'. This simplifies the implementation of
'cmd_diagnose' by making it a direct alias of 'git diagnose' and removes
some code in 'scalar.c' that is duplicated in 'builtin/diagnose.c'. The
simplicity of the alias also sets up a clean deprecation path for 'scalar
diagnose' (in favor of 'git diagnose'), if that is desired in the future.

This introduces one minor change to the output of 'scalar diagnose', which
is that the prefix of the created zip archive is changed from 'scalar_' to
'git-diagnostics-'.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye aac0e8ffee builtin/bugreport.c: create '--diagnose' option
Create a '--diagnose' option for 'git bugreport' to collect additional
information about the repository and write it to a zipped archive.

The '--diagnose' option behaves effectively as an alias for simultaneously
running 'git bugreport' and 'git diagnose'. In the documentation, users are
explicitly recommended to attach the diagnostics alongside a bug report to
provide additional context to readers, ideally reducing some back-and-forth
between reporters and those debugging the issue.

Note that '--diagnose' may take an optional string arg (either 'stats' or
'all'). If specified without the arg, the behavior corresponds to running
'git diagnose' without '--mode'. As with 'git diagnose', this default is
intended to help reduce unintentional leaking of sensitive information).
Users can also explicitly specify '--diagnose=(stats|all)' to generate the
respective archive created by 'git diagnose --mode=(stats|all)'.

Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 7ecf193f7d builtin/diagnose.c: add '--mode' option
Create '--mode=<mode>' option in 'git diagnose' to allow users to optionally
select non-default diagnostic information to include in the output archive.
Additionally, document the currently-available modes, emphasizing the
importance of not sharing a '--mode=all' archive publicly due to the
presence of sensitive information.

Note that the option parsing callback - 'option_parse_diagnose()' - is added
to 'diagnose.c' rather than 'builtin/diagnose.c' so that it may be reused in
future callers configuring a diagnostics archive.

Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 6783fd3cef builtin/diagnose.c: create 'git diagnose' builtin
Create a 'git diagnose' builtin to generate a standalone zip archive of
repository diagnostics.

The "diagnose" functionality was originally implemented for Scalar in
aa5c79a331 (scalar: implement `scalar diagnose`, 2022-05-28). However, the
diagnostics gathered are not specific to Scalar-cloned repositories and
can be useful when diagnosing issues in any Git repository.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 33cba726f0 diagnose.c: add option to configure archive contents
Update 'create_diagnostics_archive()' to take an argument 'mode'. When
archiving diagnostics for a repository, 'mode' is used to selectively
include/exclude information based on its value. The initial options for
'mode' are:

* DIAGNOSE_NONE: do not collect any diagnostics or create an archive
  (no-op).
* DIAGNOSE_STATS: collect basic repository metadata (Git version, repo path,
  filesystem available space) as well as sizing and count statistics for the
  repository's objects and packfiles.
* DIAGNOSE_ALL: collect basic repository metadata, sizing/count statistics,
  and copies of the '.git', '.git/hooks', '.git/info', '.git/logs', and
  '.git/objects/info' directories.

These modes are introduced to provide users the option to collect
diagnostics without the sensitive information included in copies of '.git'
dir contents. At the moment, only 'scalar diagnose' uses
'create_diagnostics_archive()' (with a hardcoded 'DIAGNOSE_ALL' mode to
match existing functionality), but more callers will be introduced in
subsequent patches.

Finally, refactor from a hardcoded set of 'add_directory_to_archiver()'
calls to iterative invocations gated by 'DIAGNOSE_ALL'. This allows for
easier future modification of the set of directories to archive and improves
error reporting when 'add_directory_to_archiver()' fails.

Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye bb2c34956a scalar-diagnose: move functionality to common location
Move the core functionality of 'scalar diagnose' into a new 'diagnose.[c,h]'
library to prepare for new callers in the main Git tree generating
diagnostic archives. These callers will be introduced in subsequent patches.

While this patch appears large, it is mostly made up of moving code out of
'scalar.c' and into 'diagnose.c'. Specifically, the functions

- dir_file_stats_objects()
- dir_file_stats()
- count_files()
- loose_objs_stats()
- add_directory_to_archiver()

are all copied verbatim from 'scalar.c'. The 'create_diagnostics_archive()'
function is a mostly identical (partial) copy of 'cmd_diagnose()', with the
primary changes being that 'zip_path' is an input and "Enlistment root" is
corrected to "Repository root" in the archiver log.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 435a2535b7 scalar-diagnose: move 'get_disk_info()' to 'compat/'
Move 'get_disk_info()' function into 'compat/'. Although Scalar-specific
code is generally not part of the main Git tree, 'get_disk_info()' will be
used in subsequent patches by additional callers beyond 'scalar diagnose'.
This patch prepares for that change, at which point this platform-specific
code should be part of 'compat/' as a matter of convention.

The function is copied *mostly* verbatim, with two exceptions:

* '#ifdef WIN32' is replaced with '#ifdef GIT_WINDOWS_NATIVE' to allow
  'statvfs' to be used with Cygwin.
* the 'struct strbuf buf' and 'int res' (as well as their corresponding
  cleanup & return) are moved outside of the '#ifdef' block.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye ba307a5046 scalar-diagnose: add directory to archiver more gently
If a directory added to the 'scalar diagnose' archiver does not exist, warn
and return 0 from 'add_directory_to_archiver()' rather than failing with a
fatal error. This handles a failure edge case where the '.git/logs' has not
yet been created when running 'scalar diagnose', but extends to any
situation where a directory may be missing in the '.git' dir.

Now, when a directory is missing a warning is captured in the diagnostic
logs. This provides a user with more complete information than if 'scalar
diagnose' simply failed with an error.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 91be401945 scalar-diagnose: avoid 32-bit overflow of size_t
Avoid 32-bit size_t overflow when reporting the available disk space in
'get_disk_info' by casting the block size and available block count to
'off_t' before multiplying them. Without this change, 'st_mult' would
(correctly) report a size_t overflow on 32-bit systems at or exceeding 2^32
bytes of available space.

Note that 'off_t' is a 64-bit integer even on 32-bit systems due to the
inclusion of '#define _FILE_OFFSET_BITS 64' in 'git-compat-util.h' (see
b97e911643 (Support for large files on 32bit systems., 2007-02-17)).

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Victoria Dye 81ad551343 scalar-diagnose: use "$GIT_UNZIP" in test
Use the "$GIT_UNZIP" test variable rather than verbatim 'unzip' to unzip the
'scalar diagnose' archive. Using "$GIT_UNZIP" is needed to run the Scalar
tests on systems where 'unzip' is not in the system path.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:20:02 -07:00
Junio C Hamano afa70145a2 The twelfth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-12 13:19:08 -07:00
Junio C Hamano 83489a5b20 Merge branch 'ab/plug-revisions-leak'
Plug a bit more leaks in the revisions API.

* ab/plug-revisions-leak:
  revisions API: don't leak memory on argv elements that need free()-ing
  bisect.c: partially fix bisect_rev_setup() memory leak
  log: refactor "rev.pending" code in cmd_show()
  log: fix a memory leak in "git show <revision>..."
  test-fast-rebase helper: use release_revisions() (again)
  bisect.c: add missing "goto" for release_revisions()
2022-08-12 13:19:08 -07:00
Junio C Hamano 657c7403a3 Merge branch 'ab/leak-check'
Extend SANITIZE=leak checking and declare more tests "currently leak-free".

* ab/leak-check:
  CI: use "GIT_TEST_SANITIZE_LEAK_LOG=true" in linux-leaks
  upload-pack: fix a memory leak in create_pack_file()
  leak tests: mark passing SANITIZE=leak tests as leak-free
  leak tests: don't skip some tests under SANITIZE=leak
  test-lib: have the "check" mode for SANITIZE=leak consider leak logs
  test-lib: add a GIT_TEST_PASSING_SANITIZE_LEAK=check mode
  test-lib: simplify by removing test_external
  tests: move copy/pasted PERL + Test::More checks to a lib-perl.sh
  t/Makefile: don't remove test-results in "clean-except-prove-cache"
  test-lib: add a SANITIZE=leak logging mode
  t/README: reword the "GIT_TEST_PASSING_SANITIZE_LEAK" description
  test-lib: add a --invert-exit-code switch
  test-lib: fix GIT_EXIT_OK logic errors, use BAIL_OUT
  test-lib: don't set GIT_EXIT_OK before calling test_atexit_handler
  test-lib: use $1, not $@ in test_known_broken_{ok,failure}_
2022-08-12 13:19:08 -07:00