Update :/abc ambiguity check

:/abc may mean two things:

- as a revision, it means the revision that has "abc" in commit
  message.

- as a pathpec, it means "abc" from root.

Currently we see ":/abc" as a rev (most of the time), but never see it
as a pathspec even if "abc" exists and "git log :/abc" will gladly
take ":/abc" as rev even it's ambiguous. This patch makes it:

- ambiguous when "abc" exists on worktree
- a rev if abc does not exist on worktree
- a path if abc is not found in any commits (although better use
  "--" to avoid ambiguation because searching through commit DAG is
  expensive)

A plus from this patch is, because ":/" never matches anything as a
rev, it is never considered a valid rev and because root directory
always exists, ":/" is always unambiguously seen as a pathspec.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/setup.c b/setup.c
index f108c4b..47acc11 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -66,7 +66,14 @@ int check_filename(const char *prefix, const char *arg)
        const char *name;
        struct stat st;
 
-       name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
+       if (!prefixcmp(arg, ":/")) {
+               if (arg[2] == '\0') /* ":/" is root dir, always exists */
+                       return 1;
+               name = arg + 2;
+       } else if (prefix)
+               name = prefix_filename(prefix, strlen(prefix), arg);
+       else
+               name = arg;
        if (!lstat(name, &st))
                return 1; /* file exists */
        if (errno == ENOENT || errno == ENOTDIR)

diff --git a/t/t4208-log-magic-pathspec.sh b/t/t4208-log-magic-pathspec.sh
index 2c482b6..72300b5 100755 (executable)
--- a/t/t4208-log-magic-pathspec.sh
+++ b/t/t4208-log-magic-pathspec.sh
@@ -11,11 +11,24 @@ test_expect_success 'setup' '
        mkdir sub
 '
 
-test_expect_success '"git log :/" should be ambiguous' '
-       test_must_fail git log :/ 2>error &&
+test_expect_success '"git log :/" should not be ambiguous' '
+       git log :/
+'
+
+test_expect_success '"git log :/a" should be ambiguous (applied both rev and worktree)' '
+       : >a &&
+       test_must_fail git log :/a 2>error &&
        grep ambiguous error
 '
 
+test_expect_success '"git log :/a -- " should not be ambiguous' '
+       git log :/a --
+'
+
+test_expect_success '"git log -- :/a" should not be ambiguous' '
+       git log -- :/a
+'
+
 test_expect_success '"git log :" should be ambiguous' '
        test_must_fail git log : 2>error &&
        grep ambiguous error