[PATCH 3/8] pathspec: change PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE flag

[Brandon Williams <bmwill@google.com>]

It's confusing to have two different 'strip submodule slash' flags which
do subtly different things.  Both
PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE and
PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP will accomplish the same task of
striping a slash from a pathspec which matches a submodule entry in the
index.  The only difference is that
PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE will perform additional checks
and die if a pathspec has a leading path component which corresponds to
a submodule.  This additional functionality should be split out into its
own flag.

To this end, rename the PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE flag to
PATHSPEC_SUBMODULE_LEADING_PATH and change its behavior to only die if a
path descends into a submodule.  In addition add the
PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP flag to callers which relied on the
old slash stripping functionality.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 builtin/add.c          |  3 ++-
 builtin/check-ignore.c |  3 ++-
 pathspec.c             | 32 ++++++++++++++++----------------
 pathspec.h             |  9 +++------
 4 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/builtin/add.c b/builtin/add.c
index ec58e3679..2aa9aeab9 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -389,7 +389,8 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 	parse_pathspec(&pathspec, 0,
 		       PATHSPEC_PREFER_FULL |
 		       PATHSPEC_SYMLINK_LEADING_PATH |
-		       PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE,
+		       PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
+		       PATHSPEC_SUBMODULE_LEADING_PATH,
 		       prefix, argv);
 
 	if (add_new_files) {
diff --git a/builtin/check-ignore.c b/builtin/check-ignore.c
index 1d73d3ca3..73237b2b1 100644
--- a/builtin/check-ignore.c
+++ b/builtin/check-ignore.c
@@ -87,7 +87,8 @@ static int check_ignore(struct dir_struct *dir,
 	parse_pathspec(&pathspec,
 		       PATHSPEC_ALL_MAGIC & ~PATHSPEC_FROMTOP,
 		       PATHSPEC_SYMLINK_LEADING_PATH |
-		       PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE |
+		       PATHSPEC_SUBMODULE_LEADING_PATH |
+		       PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP |
 		       PATHSPEC_KEEP_ORDER,
 		       prefix, argv);
 
diff --git a/pathspec.c b/pathspec.c
index e37256c3b..f37d5769d 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -398,29 +398,29 @@ static void strip_submodule_slash_cheap(struct pathspec_item *item)
 	}
 }
 
-static void strip_submodule_slash_expensive(struct pathspec_item *item)
+static void die_path_inside_submodule(const struct pathspec_item *item,
+				      const struct index_state *istate)
 {
 	int i;
 
-	for (i = 0; i < active_nr; i++) {
-		struct cache_entry *ce = active_cache[i];
+	for (i = 0; i < istate->cache_nr; i++) {
+		struct cache_entry *ce = istate->cache[i];
 		int ce_len = ce_namelen(ce);
 
 		if (!S_ISGITLINK(ce->ce_mode))
 			continue;
 
-		if (item->len <= ce_len || item->match[ce_len] != '/' ||
-		    memcmp(ce->name, item->match, ce_len))
+		if (item->len <= ce_len)
+			continue;
+		if (item->match[ce_len] != '/')
+			continue;
+		if (strncmp(ce->name, item->match, ce_len))
+			continue;
+		if (item->len == ce_len + 1)
 			continue;
 
-		if (item->len == ce_len + 1) {
-			/* strip trailing slash */
-			item->len--;
-			item->match[item->len] = '\0';
-		} else {
-			die(_("Pathspec '%s' is in submodule '%.*s'"),
-			    item->original, ce_len, ce->name);
-		}
+		die(_("Pathspec '%s' is in submodule '%.*s'"),
+		    item->original, ce_len, ce->name);
 	}
 }
 
@@ -499,9 +499,6 @@ static void init_pathspec_item(struct pathspec_item *item, unsigned flags,
 	if (flags & PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP)
 		strip_submodule_slash_cheap(item);
 
-	if (flags & PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE)
-		strip_submodule_slash_expensive(item);
-
 	if (magic & PATHSPEC_LITERAL) {
 		item->nowildcard_len = item->len;
 	} else {
@@ -639,6 +636,9 @@ void parse_pathspec(struct pathspec *pathspec,
 			die(_("pathspec '%s' is beyond a symbolic link"), entry);
 		}
 
+		if (flags & PATHSPEC_SUBMODULE_LEADING_PATH)
+			die_path_inside_submodule(item + i, &the_index);
+
 		if (item[i].nowildcard_len < item[i].len)
 			pathspec->has_wildcard = 1;
 		pathspec->magic |= item[i].magic;
diff --git a/pathspec.h b/pathspec.h
index 55e976972..93a819cbf 100644
--- a/pathspec.h
+++ b/pathspec.h
@@ -63,13 +63,10 @@ struct pathspec {
 /* die if a symlink is part of the given path's directory */
 #define PATHSPEC_SYMLINK_LEADING_PATH (1<<4)
 /*
- * This is like a combination of ..LEADING_PATH and .._SLASH_CHEAP
- * (but not the same): it strips the trailing slash if the given path
- * is a gitlink but also checks and dies if gitlink is part of the
- * leading path (i.e. the given path goes beyond a submodule). It's
- * safer than _SLASH_CHEAP and also more expensive.
+ * Checks and dies if gitlink is part of the leading path
+ * (i.e. the given path goes beyond a submodule).
  */
-#define PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE (1<<5)
+#define PATHSPEC_SUBMODULE_LEADING_PATH (1<<5)
 #define PATHSPEC_PREFIX_ORIGIN (1<<6)
 #define PATHSPEC_KEEP_ORDER (1<<7)
 /*
-- 
2.13.0.rc2.291.g57267f2277-goog