[PATCH v6 5/6] http: permit unlinking partial packs on Windows
- From
Ted Nyman <tnyman@openai.com>
- Date
- Jul 27, 2026, 00:28 UTC
- Message-ID
- <87a20ac80fcaaaa3f69a24a650f5c135b24956ff.1785111375.git.tnyman@openai.com>
- In-Reply-To
- <cover.1785111375.git.tnyman@openai.com>
On Windows, an open file must permit FILE_SHARE_DELETE before another process can unlink it. MinGW's non-append O_RDWR open enables that sharing mode only for an existing file; adding O_CREAT falls back to _wopen(), which cannot set it.
First try opening the partial pack without O_CREAT. If it does not exist, create it exclusively, close that descriptor, and retry through the existing-file path. A racing creator retries after EEXIST.
This ensures that every retained descriptor permits another downloader to unlink the staging path. Add an unlink-while-indexing test that does not require FIFOs and can therefore run on MinGW.
Signed-off-by: Ted Nyman <tnyman@openai.com> --- http.c | 17 ++++++++++++++++- t/t5550-http-fetch-dumb.sh | 21 +++++++++++++++++++++ 2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/http.c b/http.c index ad07ef3549..a0d399b274 100644 --- a/http.c +++ b/http.c @@ -2746,7 +2746,22 @@ struct http_pack_request *new_direct_http_pack_request( odb_pack_name(the_repository, &preq->tmpfile, packed_git_hash, "pack"); strbuf_addstr(&preq->tmpfile, ".temp"); - fd = open(preq->tmpfile.buf, O_RDWR | O_CREAT, 0666); + /* + * MinGW's non-append O_RDWR open grants FILE_SHARE_DELETE only for an + * existing file; reopen a newly created file so others may unlink it. + */ + for (;;) { + fd = open(preq->tmpfile.buf, O_RDWR); + if (fd >= 0 || errno != ENOENT) + break; + fd = open(preq->tmpfile.buf, O_RDWR | O_CREAT | O_EXCL, 0666); + if (fd >= 0) { + close(fd); + continue; + } + if (errno != EEXIST) + break; + } if (fd < 0) { error_errno("unable to open local file %s for pack", preq->tmpfile.buf); diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh index 86b9d87ef5..b5758f1c9c 100755 --- a/t/t5550-http-fetch-dumb.sh +++ b/t/t5550-http-fetch-dumb.sh @@ -328,6 +328,27 @@ test_expect_success 'http-fetch --packfile resumes a partial download' ' git -C packfileclient-resume cat-file -e "$HASH" ' +test_expect_success 'http-fetch --packfile permits unlink while indexing' ' + git init packfileclient-unlink && + p=$(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git && + ls objects/pack/pack-*.pack) && + tmpfile="packfileclient-unlink/.git/objects/pack/pack-$ARBITRARY.pack.temp" && + write_script git-unlink-index-pack <<-\EOF && + test -f "$GIT_TEST_PACK_TEMP" || exit 1 + rm "$GIT_TEST_PACK_TEMP" || exit 1 + exec git index-pack "$@" + EOF + test_when_finished "rm -f git-unlink-index-pack" && + PATH="$TRASH_DIRECTORY:$PATH" \ + GIT_TEST_PACK_TEMP="$TRASH_DIRECTORY/$tmpfile" \ + git -C packfileclient-unlink http-fetch --packfile="$ARBITRARY" \ + --index-pack-arg=unlink-index-pack \ + --index-pack-arg=--stdin --index-pack-arg=--keep \ + "$HTTPD_URL/dumb/repo_pack.git/$p" >out && + test_path_is_missing "$tmpfile" && + git -C packfileclient-unlink cat-file -e "$HASH" +' + test_expect_success PERL,PIPE 'concurrent http-fetch --packfile cannot corrupt an overlapping download' ' git init packfileclient-overlap && blob=$(test-tool genrandom pack-overlap 2m |
-- 2.55.0.openai.131.g83a728de1eb6