Re: [RFC PATCH] rev-parse: fix segfault with missing --path-format argument
From: Junio C Hamano <hidden>
Date: 2021-05-16 12:53:11
Wolfgang Müller [off-list ref] writes:
Calling "git rev-parse --path-format" without an argument segfaults instead of giving an error message. Commit fac60b8925 (rev-parse: add option for absolute or relative path formatting, 2020-12-13) added the argument parsing code but forgot to handle NULL. Returning an error makes sense here because there is no default value we could use. Add a test case to verify. Signed-off-by: Wolfgang Müller <redacted> --- Since this is my first contribution to the project and I'm still learning the ropes, I left this patch as RFC. For a bit of background information, I ran into this expecting the following to work: git rev-parse --path-format relative --show-toplevel I'm unsure how many git subcommands specifically require "=" between the option and the argument, but before now I always expected things to "just work" when leaving it out. This fix is based on maint. Thanks for your time and attention.
Nicely done.
quoted hunk
builtin/rev-parse.c | 2 ++ t/t1500-rev-parse.sh | 4 ++++ 2 files changed, 6 insertions(+)diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c index 85bad9052e..7af8dab8bc 100644 --- a/builtin/rev-parse.c +++ b/builtin/rev-parse.c@@ -759,6 +759,8 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix) continue; } if (opt_with_value(arg, "--path-format", &arg)) { + if (!arg) + die("--path-format requires an argument");
As die() is end-user facing, you'd probably want
die(_("--path-format requires an argument"));
We do have untranslated die() nearby for the same option, which may
want to be cleaned up either in a preliminary patch, or in this same
patch as an unrelated fix "while we are at it".
quoted hunk
if (!strcmp(arg, "absolute")) { format = FORMAT_CANONICAL; } else if (!strcmp(arg, "relative")) {diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh index deae916707..a1a8ce5265 100755 --- a/t/t1500-rev-parse.sh +++ b/t/t1500-rev-parse.sh@@ -146,6 +146,10 @@ test_expect_success '--path-format can change in the middle of the command line' test_cmp expect actual ' +test_expect_success '--path-format does not segfault without an argument' ' + test_must_fail git rev-parse --path-format --show-toplevel
The above is certainly worth testing for, but if we ever upgrade the command line parser of "rev-parse" to be compatible with the parser based on the parse-options API to allow both "--opt=val" and "--opt val", it will start to fail for an entirely different reason, namely "--show-toplevel" will be taken as the argument to "--path-format", and we'd get "unknown argument to --path-format". So it might be prudent to test both, i.e. test_must_fail git rev-parse --path-format --show-toplevel && test_must_fail git rev-parse --show-toplevel --path-format