[PATCH 2/8] submodule: add die_in_unpopulated_submodule function

[Brandon Williams <bmwill@google.com>]

Currently 'git add' is the only command which dies when launched from an
unpopulated submodule (the place-holder directory for a submodule which
hasn't been checked out).  This is triggered implicitly by passing the
PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE flag to 'parse_pathspec()'.

Instead make this desire more explicit by creating a function
'die_in_unpopulated_submodule()' which dies if the provided 'prefix' has
a leading path component which matches a submodule in the the index.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 builtin/add.c                    |  3 +++
 pathspec.c                       | 29 -----------------------------
 submodule.c                      | 30 ++++++++++++++++++++++++++++++
 submodule.h                      |  2 ++
 t/t6134-pathspec-in-submodule.sh |  6 +-----
 5 files changed, 36 insertions(+), 34 deletions(-)

diff --git a/builtin/add.c b/builtin/add.c
index 9f53f020d..ec58e3679 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -17,6 +17,7 @@
 #include "revision.h"
 #include "bulk-checkin.h"
 #include "argv-array.h"
+#include "submodule.h"
 
 static const char * const builtin_add_usage[] = {
 	N_("git add [<options>] [--] <pathspec>..."),
@@ -379,6 +380,8 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 	if (read_cache() < 0)
 		die(_("index file corrupt"));
 
+	die_in_unpopulated_submodule(&the_index, prefix);
+
 	/*
 	 * Check the "pathspec '%s' did not match any files" block
 	 * below before enabling new magic.
diff --git a/pathspec.c b/pathspec.c
index 61b5b1273..e37256c3b 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -424,27 +424,6 @@ static void strip_submodule_slash_expensive(struct pathspec_item *item)
 	}
 }
 
-static void die_inside_submodule_path(struct pathspec_item *item)
-{
-	int i;
-
-	for (i = 0; i < active_nr; i++) {
-		struct cache_entry *ce = active_cache[i];
-		int ce_len = ce_namelen(ce);
-
-		if (!S_ISGITLINK(ce->ce_mode))
-			continue;
-
-		if (item->len < ce_len ||
-		    !(item->match[ce_len] == '/' || item->match[ce_len] == '\0') ||
-		    memcmp(ce->name, item->match, ce_len))
-			continue;
-
-		die(_("Pathspec '%s' is in submodule '%.*s'"),
-		    item->original, ce_len, ce->name);
-	}
-}
-
 /*
  * Perform the initialization of a pathspec_item based on a pathspec element.
  */
@@ -547,14 +526,6 @@ static void init_pathspec_item(struct pathspec_item *item, unsigned flags,
 	/* sanity checks, pathspec matchers assume these are sane */
 	if (item->nowildcard_len > item->len ||
 	    item->prefix         > item->len) {
-		/*
-		 * This case can be triggered by the user pointing us to a
-		 * pathspec inside a submodule, which is an input error.
-		 * Detect that here and complain, but fallback in the
-		 * non-submodule case to a BUG, as we have no idea what
-		 * would trigger that.
-		 */
-		die_inside_submodule_path(item);
 		die ("BUG: error initializing pathspec_item");
 	}
 }
diff --git a/submodule.c b/submodule.c
index 7c3c4b17f..9e0502f25 100644
--- a/submodule.c
+++ b/submodule.c
@@ -281,6 +281,36 @@ int is_submodule_populated_gently(const char *path, int *return_error_code)
 	return ret;
 }
 
+/*
+ * Dies if the provided 'prefix' corresponds to an unpopulated submodule
+ */
+void die_in_unpopulated_submodule(const struct index_state *istate,
+				  const char *prefix)
+{
+	int i, prefixlen;
+
+	if (!prefix)
+		return;
+
+	prefixlen = strlen(prefix);
+
+	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 (prefixlen <= ce_len)
+			continue;
+		if (strncmp(ce->name, prefix, ce_len))
+			continue;
+		if (prefix[ce_len] != '/')
+			continue;
+
+		die(_("in unpopulated submodule '%s'"), ce->name);
+	}
+}
+
 int parse_submodule_update_strategy(const char *value,
 		struct submodule_update_strategy *dst)
 {
diff --git a/submodule.h b/submodule.h
index 8a8bc49dc..f4fe6374d 100644
--- a/submodule.h
+++ b/submodule.h
@@ -48,6 +48,8 @@ extern int is_submodule_initialized(const char *path);
  * Otherwise the return error code is the same as of resolve_gitdir_gently.
  */
 extern int is_submodule_populated_gently(const char *path, int *return_error_code);
+extern void die_in_unpopulated_submodule(const struct index_state *istate,
+					 const char *prefix);
 extern int parse_submodule_update_strategy(const char *value,
 		struct submodule_update_strategy *dst);
 extern const char *submodule_strategy_to_string(const struct submodule_update_strategy *s);
diff --git a/t/t6134-pathspec-in-submodule.sh b/t/t6134-pathspec-in-submodule.sh
index fd401ca60..0f1cb49ce 100755
--- a/t/t6134-pathspec-in-submodule.sh
+++ b/t/t6134-pathspec-in-submodule.sh
@@ -24,13 +24,9 @@ test_expect_success 'error message for path inside submodule' '
 	test_cmp expect actual
 '
 
-cat <<EOF >expect
-fatal: Pathspec '.' is in submodule 'sub'
-EOF
-
 test_expect_success 'error message for path inside submodule from within submodule' '
 	test_must_fail git -C sub add . 2>actual &&
-	test_cmp expect actual
+	test_i18ngrep "in unpopulated submodule" actual
 '
 
 test_done
-- 
2.13.0.rc2.291.g57267f2277-goog