pathspec: stop --*-pathspecs impact on internal parse_pathspec() uses

Normally parse_pathspec() is used on command line arguments where it
can do fancy thing like parsing magic on each argument or adding magic
for all pathspecs based on --*-pathspecs options.

There's another use of parse_pathspec(), where pathspec is needed, but
the input is known to be pure paths. In this case we usually don't
want --*-pathspecs to interfere. And we definitely do not want to
parse magic in these paths, regardless of --literal-pathspecs.

Add new flag PATHSPEC_LITERAL_PATH for this purpose. When it's set,
--*-pathspecs are ignored, no magic is parsed. And if the caller
allows PATHSPEC_LITERAL (i.e. the next calls can take literal magic),
then PATHSPEC_LITERAL will be set.

This fixes cases where git chokes when GIT_*_PATHSPECS are set because
parse_pathspec() indicates it won't take any magic. But
GIT_*_PATHSPECS add them anyway. These are

   export GIT_LITERAL_PATHSPECS=1
   git blame -- something
   git log --follow something
   git log --merge

"git ls-files --with-tree=path" (aka parse_pathspec() in
overlay_tree_on_cache()) is safe because the input is empty, and
producing one pathspec due to PATHSPEC_PREFER_CWD does not take any
magic into account.

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

1 files changed, 8 insertions, 1 deletions

diff --git a/pathspec.c b/pathspec.c
index ad1a9f5b28..4cf2bd365a 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -128,7 +128,11 @@ static unsigned prefix_pathspec(struct pathspec_item *item,
 		die(_("global 'literal' pathspec setting is incompatible "
 		      "with all other global pathspec settings"));
 
-	if (elt[0] != ':' || literal_global) {
+	if (flags & PATHSPEC_LITERAL_PATH)
+		global_magic = 0;
+
+	if (elt[0] != ':' || literal_global ||
+	    (flags & PATHSPEC_LITERAL_PATH)) {
 		; /* nothing to do */
 	} else if (elt[1] == '(') {
 		/* longhand */
@@ -405,6 +409,9 @@ void parse_pathspec(struct pathspec *pathspec,
 		item[i].magic = prefix_pathspec(item + i, &short_magic,
 						argv + i, flags,
 						prefix, prefixlen, entry);
+		if ((flags & PATHSPEC_LITERAL_PATH) &&
+		    !(magic_mask & PATHSPEC_LITERAL))
+			item[i].magic |= PATHSPEC_LITERAL;
 		if (item[i].magic & magic_mask)
 			unsupported_magic(entry,
 					  item[i].magic & magic_mask,