1f2e05f0b7 ("wildmatch: fix exponential behavior", 2023-03-20)
introduced a new test with a background process. Backgrounding
necessarily gives a result of 0, so that a seemingly broken && chain is
not really broken.
Adjust t3070 slightly so that our chain lint test recognizes the
construct for what it is and does not raise a false positive.
Signed-off-by: Michael J Gruber <git@grubix.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
WM_ABORT_ALL and WM_ABORT_TO_STARSTAR are used internally to limit
backtracking when a match fails, they are not of interest to the caller
and so should not be public.
Suggested-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code changed in this commit is designed to check if the pattern
starts with "**/" or contains "/**/" (see 3a078dec33 (wildmatch: fix
"**" special case, 2013-01-01)). Unfortunately when the pattern begins
with "**/" `prev_p = p - 2` is evaluated when `p` points to the second
"*" and so the subtraction is undefined according to section 6.5.6 of
the C standard because the result does not point within the same object
as `p`. Fix this by avoiding the subtraction unless it is well defined.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When dowild() cannot match a '*' or '/**/' wildcard then it must return
WM_ABORT_TO_STARSTAR or WM_ABORT_ALL respectively. Failure to observe
this results in unnecessary backtracking and the time taken for a failed
match increases exponentially with the number of wildcards in the
pattern [1]. Unfortunately in some instances dowild() returns WM_NOMATCH
for a failed match resulting in long match times for patterns containing
multiple wildcards as can be seen in the following benchmark.
(Note that the timings in the Benchmark 1 are really measuring the time
to execute test-tool rather than the time to match the pattern)
Benchmark 1: t/helper/test-tool wildmatch wildmatch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab "*a"
Time (mean ± σ): 22.8 ms ± 1.7 ms [User: 12.1 ms, System: 10.6 ms]
Range (min … max): 19.4 ms … 26.9 ms 113 runs
Warning: Ignoring non-zero exit code.
Benchmark 2: t/helper/test-tool wildmatch wildmatch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab "*a*a*a*a*a*a*a*a*a"
Time (mean ± σ): 5.244 s ± 0.228 s [User: 5.229 s, System: 0.010 s]
Range (min … max): 4.969 s … 5.707 s 10 runs
Warning: Ignoring non-zero exit code.
Summary
't/helper/test-tool wildmatch wildmatch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab "*a"' ran
230.37 ± 20.04 times faster than 't/helper/test-tool wildmatch wildmatch aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab "*a*a*a*a*a*a*a*a*a"'
The security implications are limited as it only affects operations that
are potentially DoS vectors. For example by creating a blob containing
such a pattern a malicious user can exploit this behavior to use large
amounts of CPU time on a remote server by pushing the blob and then
creating a new clone with --filter=sparse:oid. However this filter type
is usually disabled as it is known to consume large amounts of CPU time
even without this bug.
The WM_MATCH changed in the first hunk of this patch comes from the
original implementation imported from rsync in 5230f605e1 (Import
wildmatch from rsync, 2012-10-15). Compared to the others converted here
it is fairly harmless as it only triggers at the end of the pattern and
so will only cause a single unnecessary backtrack. The others introduced
by 6f1a31f0aa (wildmatch: advance faster in <asterisk> + <literal>
patterns, 2013-01-01) and 46983441ae (wildmatch: make a special case for
"*/" with FNM_PATHNAME, 2013-01-01) are more pernicious and will cause
exponential behavior.
A new test is added to protect against future regressions.
[1] https://research.swtch.com/glob
Helped-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up around unused function parameters.
* jk/unused-post-2.39:
userdiff: mark unused parameter in internal callback
list-objects-filter: mark unused parameters in virtual functions
diff: mark unused parameters in callbacks
xdiff: mark unused parameter in xdl_call_hunk_func()
xdiff: drop unused parameter in def_ff()
ws: drop unused parameter from ws_blank_line()
list-objects: drop process_gitlink() function
blob: drop unused parts of parse_blob_buffer()
ls-refs: use repository parameter to iterate refs
Clarify how "checkout -b/-B" and "git branch [-f]" are similar but
different in the documentation.
* jc/doc-checkout-b:
checkout: document -b/-B to highlight the differences from "git branch"
Document that "branch -f <branch>" disables only the safety to
avoid recreating an existing branch.
* jc/doc-branch-update-checked-out-branch:
branch: document `-f` and linked worktree behaviour
"git ls-tree --format='%(path) %(path)' $tree $path" showed the
path three times, which has been corrected.
* rs/ls-tree-path-expansion-fix:
ls-tree: remove dead store and strbuf for quote_c_style()
ls-tree: fix expansion of repeated %(path)
Document ORIG_HEAD a bit more.
* pb/doc-orig-head:
git-rebase.txt: add a note about 'ORIG_HEAD' being overwritten
revisions.txt: be explicit about commands writing 'ORIG_HEAD'
git-merge.txt: mention 'ORIG_HEAD' in the Description
git-reset.txt: mention 'ORIG_HEAD' in the Description
git-cherry-pick.txt: do not use 'ORIG_HEAD' in example
The logic to see if we are using the "cone" mode by checking the
sparsity patterns has been tightened to avoid mistaking a pattern
that names a single file as specifying a cone.
* ws/single-file-cone:
dir: check for single file cone patterns
"git diff --relative" did not mix well with "git diff --ext-diff",
which has been corrected.
* jk/ext-diff-with-relative:
diff: drop "name" parameter from prepare_temp_file()
diff: clean up external-diff argv setup
diff: use filespec path to set up tempfiles for ext-diff
Fix to a small regression in 2.38 days.
* ab/bundle-wo-args:
bundle <cmd>: have usage_msg_opt() note the missing "<file>"
builtin/bundle.c: remove superfluous "newargc" variable
bundle: don't segfault on "git bundle <subcmd>"
Fix the sequence to fsync $GIT_DIR/packed-refs file that forgot to
flush its output to the disk..
* ps/fsync-refs-fix:
refs: fix corruption by not correctly syncing packed-refs to disk
When given a pattern that matches an empty string at the end of a
line, the code to parse the "git diff" line-ranges fell into an
infinite loop, which has been corrected.
* lk/line-range-parsing-fix:
line-range: fix infinite loop bug with '$' regex
Newer regex library macOS stopped enabling GNU-like enhanced BRE,
where '\(A\|B\)' works as alternation, unless explicitly asked with
the REG_ENHANCED flag. "git grep" now can be compiled to do so, to
retain the old behaviour.
* rs/use-enhanced-bre-on-macos:
use enhanced basic regular expressions on macOS
Deal with a few deprecation warning from cURL library.
* jk/curl-avoid-deprecated-api:
http: support CURLOPT_PROTOCOLS_STR
http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION
http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT
Redefining system functions for a few functions did not follow our
usual "implement git_foo() and #define foo(args) git_foo(args)"
pattern, which has broken build for some folks.
* jk/avoid-redef-system-functions-2.30:
git-compat-util: undefine system names before redeclaring them
git-compat-util: avoid redefining system function names
CI updates. We probably want a clean-up to move the long shell
script embedded in yaml file into a separate file, but that can
come later.
* cw/ci-whitespace:
ci (check-whitespace): move to actions/checkout@v3
ci (check-whitespace): add links to job output
ci (check-whitespace): suggest fixes for errors
* maint-2.35:
Git 2.35.7
Git 2.34.7
http: support CURLOPT_PROTOCOLS_STR
http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION
http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT
Git 2.33.7
Git 2.32.6
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
* maint-2.34:
Git 2.34.7
http: support CURLOPT_PROTOCOLS_STR
http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION
http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT
Git 2.33.7
Git 2.32.6
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
* maint-2.33:
Git 2.33.7
Git 2.32.6
Git 2.31.7
Git 2.30.8
apply: fix writing behind newly created symbolic links
dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS
clone: delay picking a transport until after get_repo_path()
t5619: demonstrate clone_local() with ambiguous transport
Deal with a few deprecation warning from cURL library.
* jk/curl-avoid-deprecated-api:
http: support CURLOPT_PROTOCOLS_STR
http: prefer CURLOPT_SEEKFUNCTION to CURLOPT_IOCTLFUNCTION
http-push: prefer CURLOPT_UPLOAD to CURLOPT_PUT
