From cb7bd777dc228a0a53b1ad3d60db91bfb03fcad8 Mon Sep 17 00:00:00 2001 From: Michael Montalbo Date: Sun, 31 May 2026 13:01:06 -0700 Subject: [PATCH] sub-process: use gentle handshake to avoid die() on startup failure When the configured subprocess command contains shell metacharacters (such as a space), prepare_shell_cmd() wraps it in "sh -c ". The shell itself always starts successfully, so start_command() returns zero even if the tool inside does not exist. The subsequent handshake then reads from a dead pipe and calls die() via the non-gentle packet_read_line(), killing the parent process instead of letting it handle the error. Before this change, a missing filter process at a path containing spaces produces a confusing error: $ git -c filter.myfilter.process="/path with space/tool" \ -c filter.myfilter.required=true add file.txt /path with space/tool: line 1: /path: No such file or directory fatal: the remote end hung up unexpectedly After this change, the proper error is reported: $ git ... add file.txt /path with space/tool: line 1: /path: No such file or directory error: could not read greeting from subprocess '/path with space/tool' error: initialization for subprocess '/path with space/tool' failed fatal: file.txt: clean filter 'myfilter' failed Switch the subprocess handshake from the dying packet_read_line() to packet_read_line_gently() so that a process that exits during startup produces an error return instead of killing the caller. This affects any subprocess consumer whose command path contains spaces. On Windows this routinely happens because programs live under "C:/Program Files/...", and MSYS2 path conversion can rewrite absolute paths to include that prefix. On POSIX it triggers whenever the configured path naturally contains a space or other metacharacter. convert.c (filter..process, used by git-lfs and custom clean/smudge filters) is the primary affected consumer. Signed-off-by: Michael Montalbo --- sub-process.c | 26 ++++++++++++++++++++------ t/t0021-conversion.sh | 17 +++++++++++++++++ 2 files changed, 37 insertions(+), 6 deletions(-) diff --git a/sub-process.c b/sub-process.c index 83bf0a0e82e56d..2d5c965169727b 100644 --- a/sub-process.c +++ b/sub-process.c @@ -132,17 +132,24 @@ static int handshake_version(struct child_process *process, if (packet_flush_gently(process->in)) return error("Could not write flush packet"); - if (!(line = packet_read_line(process->out, NULL)) || - !skip_prefix(line, welcome_prefix, &p) || + if (packet_read_line_gently(process->out, NULL, &line) < 0) + return error("could not read greeting from subprocess '%s'", + process->args.v[0]); + if (!line || !skip_prefix(line, welcome_prefix, &p) || strcmp(p, "-server")) return error("Unexpected line '%s', expected %s-server", line ? line : "", welcome_prefix); - if (!(line = packet_read_line(process->out, NULL)) || - !skip_prefix(line, "version=", &p) || + if (packet_read_line_gently(process->out, NULL, &line) < 0) + return error("could not read version from subprocess '%s'", + process->args.v[0]); + if (!line || !skip_prefix(line, "version=", &p) || strtol_i(p, 10, chosen_version)) return error("Unexpected line '%s', expected version", line ? line : ""); - if ((line = packet_read_line(process->out, NULL))) + if (packet_read_line_gently(process->out, NULL, &line) < 0) + return error("could not read version flush from subprocess '%s'", + process->args.v[0]); + if (line) return error("Unexpected line '%s', expected flush", line); /* Check to make sure that the version received is supported */ @@ -171,8 +178,15 @@ static int handshake_capabilities(struct child_process *process, if (packet_flush_gently(process->in)) return error("Could not write flush packet"); - while ((line = packet_read_line(process->out, NULL))) { + for (;;) { const char *p; + int len = packet_read_line_gently(process->out, NULL, &line); + + if (len < 0) + return error("could not read capabilities from subprocess '%s'", + process->args.v[0]); + if (!line) + break; if (!skip_prefix(line, "capability=", &p)) continue; diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh index f0d50d769e9fc5..033b00a364ee7a 100755 --- a/t/t0021-conversion.sh +++ b/t/t0021-conversion.sh @@ -857,6 +857,23 @@ test_expect_success 'invalid process filter must fail (and not hang!)' ' ) ' +test_expect_success 'missing process filter with space in path does not die' ' + test_config_global filter.protocol.process "/non existent/tool" && + test_config_global filter.protocol.required true && + rm -rf repo && + mkdir repo && + ( + cd repo && + git init && + + echo "*.r filter=protocol" >.gitattributes && + + cp "$TEST_ROOT/test.o" test.r && + test_must_fail git add . 2>git-stderr.log && + test_grep "clean filter.*protocol.*failed" git-stderr.log + ) +' + test_expect_success 'delayed checkout in process filter' ' test_config_global filter.a.process "test-tool rot13-filter --log=a.log clean smudge delay" && test_config_global filter.a.required true &&