Merge branch 'py/diff-submodule'

* py/diff-submodule:
  is_racy_timestamp(): do not check timestamp for gitlinks
  diff-lib.c: rename check_work_tree_entity()
  diff: a submodule not checked out is not modified
  Add t7506 to test submodule related functions for git-status
  t4027: test diff for submodule with empty directory

diff-lib.c

@@ -337,11 +337,17 @@ int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 	}
 	return run_diff_files(revs, options);
 }
+
 /*
- * See if work tree has an entity that can be staged.  Return 0 if so,
- * return 1 if not and return -1 if error.
+ * Has the work tree entity been removed?
+ *
+ * Return 1 if it was removed from the work tree, 0 if an entity to be
+ * compared with the cache entry ce still exists (the latter includes
+ * the case where a directory that is not a submodule repository
+ * exists for ce that is a submodule -- it is a submodule that is not
+ * checked out).  Return negative for an error.
  */
-static int check_work_tree_entity(const struct cache_entry *ce, struct stat *st, char *symcache)
+static int check_removed(const struct cache_entry *ce, struct stat *st, char *symcache)
 {
 	if (lstat(ce->name, st) < 0) {
 		if (errno != ENOENT && errno != ENOTDIR)
@@ -352,7 +358,20 @@ static int check_work_tree_entity(const struct cache_entry *ce, struct stat *st,
 		return 1;
 	if (S_ISDIR(st->st_mode)) {
 		unsigned char sub[20];
-		if (resolve_gitlink_ref(ce->name, "HEAD", sub))
+
+		/*
+		 * If ce is already a gitlink, we can have a plain
+		 * directory (i.e. the submodule is not checked out),
+		 * or a checked out submodule.  Either case this is not
+		 * a case where something was removed from the work tree,
+		 * so we will return 0.
+		 *
+		 * Otherwise, if the directory is not a submodule
+		 * repository, that means ce which was a blob turned into
+		 * a directory --- the blob was removed!
+		 */
+		if (!S_ISGITLINK(ce->ce_mode) &&
+		    resolve_gitlink_ref(ce->name, "HEAD", sub))
 			return 1;
 	}
 	return 0;
@@ -402,7 +421,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			memset(&(dpath->parent[0]), 0,
 			       sizeof(struct combine_diff_parent)*5);
 
-			changed = check_work_tree_entity(ce, &st, symcache);
+			changed = check_removed(ce, &st, symcache);
 			if (!changed)
 				dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 			else {
@@ -466,7 +485,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 		if (ce_uptodate(ce))
 			continue;
 
-		changed = check_work_tree_entity(ce, &st, symcache);
+		changed = check_removed(ce, &st, symcache);
 		if (changed) {
 			if (changed < 0) {
 				perror(ce->name);
@@ -527,7 +546,7 @@ static int get_stat_data(struct cache_entry *ce,
 	if (!cached) {
 		int changed;
 		struct stat st;
-		changed = check_work_tree_entity(ce, &st, cbdata->symcache);
+		changed = check_removed(ce, &st, cbdata->symcache);
 		if (changed < 0)
 			return -1;
 		else if (changed) {

read-cache.c

@@ -198,7 +198,8 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 
 static int is_racy_timestamp(const struct index_state *istate, struct cache_entry *ce)
 {
-	return (istate->timestamp &&
+	return (!S_ISGITLINK(ce->ce_mode) &&
+		istate->timestamp &&
 		((unsigned int)istate->timestamp) <= ce->ce_mtime);
 }
 

t/t4027-diff-submodule.sh

@@ -50,4 +50,11 @@ test_expect_success 'git diff-files --raw' '
 	test_cmp expect actual.files
 '
 
+test_expect_success 'git diff (empty submodule dir)' '
+	: >empty &&
+	rm -rf sub/* sub/.git &&
+	git diff > actual.empty &&
+	test_cmp empty actual.empty
+'
+
 test_done

t/t7506-status-submodule.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+test_description='git-status for submodule'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_create_repo sub
+	cd sub &&
+	: >bar &&
+	git add bar &&
+	git commit -m " Add bar" &&
+	cd .. &&
+	git add sub &&
+	git commit -m "Add submodule sub"
+'
+
+test_expect_success 'status clean' '
+	git status |
+	grep "nothing to commit"
+'
+test_expect_success 'status -a clean' '
+	git status -a |
+	grep "nothing to commit"
+'
+test_expect_success 'rm submodule contents' '
+	rm -rf sub/* sub/.git
+'
+test_expect_success 'status clean (empty submodule dir)' '
+	git status |
+	grep "nothing to commit"
+'
+test_expect_success 'status -a clean (empty submodule dir)' '
+	git status -a |
+	grep "nothing to commit"
+'
+
+test_done