From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx> When the user runs git diff --no-index file directory we follow the behavior of POSIX diff and rewrite the arguments as git diff --no-index file directory/file Doing that when "file" is "-" (which means "read from stdin") does not make sense so we should error out if the user asks us to compare "-" to a directory. This matches the behavior of GNU diff and diff on *BSD. Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx> --- diff-no-index.c | 12 +++++++----- t/t4053-diff-no-index.sh | 5 +++++ 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/diff-no-index.c b/diff-no-index.c index 4296940f90..77462ac2a9 100644 --- a/diff-no-index.c +++ b/diff-no-index.c @@ -218,11 +218,13 @@ static void fixup_paths(const char **path, struct strbuf *replacement) { unsigned int isdir0, isdir1; - if (path[0] == file_from_standard_input || - path[1] == file_from_standard_input) - return; - isdir0 = is_directory(path[0]); - isdir1 = is_directory(path[1]); + isdir0 = path[0] != file_from_standard_input && is_directory(path[0]); + isdir1 = path[1] != file_from_standard_input && is_directory(path[1]); + + if ((path[0] == file_from_standard_input && isdir1) || + (isdir0 && path[1] == file_from_standard_input)) + die(_("cannot compare stdin to a directory")); + if (isdir0 == isdir1) return; if (isdir0) { diff --git a/t/t4053-diff-no-index.sh b/t/t4053-diff-no-index.sh index 4e9fa0403d..5bfb282e98 100755 --- a/t/t4053-diff-no-index.sh +++ b/t/t4053-diff-no-index.sh @@ -205,4 +205,9 @@ test_expect_success POSIXPERM,SYMLINKS 'diff --no-index normalizes: mode not lik test_cmp expected actual ' +test_expect_success 'diff --no-index refuses to diff stdin and a directory' ' + test_must_fail git diff --no-index -- - a </dev/null 2>err && + grep "fatal: cannot compare stdin to a directory" err +' + test_done -- 2.40.1.852.g0a1e0755a6