add global --literal-pathspecs option

Git takes pathspec arguments in many places to limit the
scope of an operation. These pathspecs are treated not as
literal paths, but as glob patterns that can be fed to
fnmatch. When a user is giving a specific pattern, this is a
nice feature.

However, when programatically providing pathspecs, it can be
a nuisance. For example, to find the latest revision which
modified "$foo", one can use "git rev-list -- $foo". But if
"$foo" contains glob characters (e.g., "f*"), it will
erroneously match more entries than desired. The caller
needs to quote the characters in $foo, and even then, the
results may not be exactly the same as with a literal
pathspec. For instance, the depth checks in
match_pathspec_depth do not kick in if we match via fnmatch.

This patch introduces a global command-line option (i.e.,
one for "git" itself, not for specific commands) to turn
this behavior off. It also has a matching environment
variable, which can make it easier if you are a script or
porcelain interface that is going to issue many such
commands.

This option cannot turn off globbing for particular
pathspecs. That could eventually be done with a ":(noglob)"
magic pathspec prefix. However, that level of granularity is
more cumbersome to use for many cases, and doing ":(noglob)"
right would mean converting the whole codebase to use
"struct pathspec", as the usual "const char **pathspec"
cannot represent extra per-item flags.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 18fdd18f3..95608d9dc 100644
--- a/cache.h
+++ b/cache.h
@@ -362,6 +362,7 @@ static inline enum object_type object_type(unsigned int mode)
 #define GIT_NOTES_DISPLAY_REF_ENVIRONMENT "GIT_NOTES_DISPLAY_REF"
 #define GIT_NOTES_REWRITE_REF_ENVIRONMENT "GIT_NOTES_REWRITE_REF"
 #define GIT_NOTES_REWRITE_MODE_ENVIRONMENT "GIT_NOTES_REWRITE_MODE"
+#define GIT_LITERAL_PATHSPECS_ENVIRONMENT "GIT_LITERAL_PATHSPECS"
 
 /*
  * Repository-local GIT_* environment variables
@@ -490,6 +491,8 @@ extern int init_pathspec(struct pathspec *, const char **);
 extern void free_pathspec(struct pathspec *);
 extern int ce_path_match(const struct cache_entry *ce, const struct pathspec *pathspec);
 
+extern int limit_pathspec_to_literal(void);
+
 #define HASH_WRITE_OBJECT 1
 #define HASH_FORMAT_CHECK 2
 extern int index_fd(unsigned char *sha1, int fd, struct stat *st, enum object_type type, const char *path, unsigned flags);