[PATCH 17/19] submodule: use submodule repos for object lookup

[Stefan Beller <sbeller@google.com>]

This converts the 'show_submodule_header' function to use
the repository API properly, such that the submodule objects
are not added to the main object store.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 submodule.c | 48 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 10 deletions(-)

diff --git a/submodule.c b/submodule.c
index 442229bb49..5e1a6c0b7c 100644
--- a/submodule.c
+++ b/submodule.c
@@ -443,7 +443,7 @@ static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 	return prepare_revision_walk(rev);
 }
 
-static void print_submodule_summary(struct rev_info *rev, struct diff_options *o)
+static void print_submodule_summary(struct repository *r, struct rev_info *rev, struct diff_options *o)
 {
 	static const char format[] = "  %m %s";
 	struct strbuf sb = STRBUF_INIT;
@@ -454,7 +454,8 @@ static void print_submodule_summary(struct rev_info *rev, struct diff_options *o
 		ctx.date_mode = rev->date_mode;
 		ctx.output_encoding = get_log_output_encoding();
 		strbuf_setlen(&sb, 0);
-		format_commit_message(commit, format, &sb, &ctx);
+		repo_format_commit_message(r, commit, format, &sb,
+				      &ctx);
 		strbuf_addch(&sb, '\n');
 		if (commit->object.flags & SYMMETRIC_LEFT)
 			diff_emit_submodule_del(o, sb.buf);
@@ -481,12 +482,37 @@ void prepare_submodule_repo_env(struct argv_array *out)
 			 DEFAULT_GIT_DIR_ENVIRONMENT);
 }
 
+/*
+ * Initialize 'out' based on the provided submodule path.
+ *
+ * Unlike repo_submodule_init, this tolerates submodules not present
+ * in .gitmodules. NEEDSWORK: The repo_submodule_init behavior is
+ * preferrable. This function exists only to preserve historical behavior.
+ *
+ * Returns 0 on success, -1 when the submodule is not present.
+ */
+static int open_submodule(struct repository *out, const char *path)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	if (submodule_to_gitdir(&sb, path) || repo_init(out, sb.buf, NULL)) {
+		strbuf_release(&sb);
+		return -1;
+	}
+
+	out->submodule_prefix = xstrdup(path);
+
+	strbuf_release(&sb);
+	return 0;
+}
+
 /* Helper function to display the submodule header line prior to the full
  * summary output. If it can locate the submodule objects directory it will
  * attempt to lookup both the left and right commits and put them into the
  * left and right pointers.
  */
-static void show_submodule_header(struct diff_options *o, const char *path,
+static void show_submodule_header(struct diff_options *o, struct repository *sub,
+		const char *path,
 		struct object_id *one, struct object_id *two,
 		unsigned dirty_submodule,
 		struct commit **left, struct commit **right,
@@ -507,7 +533,7 @@ static void show_submodule_header(struct diff_options *o, const char *path,
 	else if (is_null_oid(two))
 		message = "(submodule deleted)";
 
-	if (add_submodule_odb(path)) {
+	if (open_submodule(sub, path) < 0) {
 		if (!message)
 			message = "(commits not present)";
 		goto output_header;
@@ -517,8 +543,8 @@ static void show_submodule_header(struct diff_options *o, const char *path,
 	 * Attempt to lookup the commit references, and determine if this is
 	 * a fast forward or fast backwards update.
 	 */
-	*left = lookup_commit_reference(the_repository, one);
-	*right = lookup_commit_reference(the_repository, two);
+	*left = lookup_commit_reference(sub, one);
+	*right = lookup_commit_reference(sub, two);
 
 	/*
 	 * Warn about missing commits in the submodule project, but only if
@@ -528,7 +554,7 @@ static void show_submodule_header(struct diff_options *o, const char *path,
 	     (!is_null_oid(two) && !*right))
 		message = "(commits not present)";
 
-	*merge_bases = get_merge_bases(*left, *right);
+	*merge_bases = repo_get_merge_bases(sub, *left, *right);
 	if (*merge_bases) {
 		if ((*merge_bases)->item == *left)
 			fast_forward = 1;
@@ -562,8 +588,9 @@ void show_submodule_summary(struct diff_options *o, const char *path,
 	struct rev_info rev;
 	struct commit *left = NULL, *right = NULL;
 	struct commit_list *merge_bases = NULL;
+	struct repository sub;
 
-	show_submodule_header(o, path, one, two, dirty_submodule,
+	show_submodule_header(o, &sub, path, one, two, dirty_submodule,
 			      &left, &right, &merge_bases);
 
 	/*
@@ -580,7 +607,7 @@ void show_submodule_summary(struct diff_options *o, const char *path,
 		goto out;
 	}
 
-	print_submodule_summary(&rev, o);
+	print_submodule_summary(&sub, &rev, o);
 
 out:
 	if (merge_bases)
@@ -598,8 +625,9 @@ void show_submodule_inline_diff(struct diff_options *o, const char *path,
 	struct commit_list *merge_bases = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf sb = STRBUF_INIT;
+	struct repository sub;
 
-	show_submodule_header(o, path, one, two, dirty_submodule,
+	show_submodule_header(o, &sub, path, one, two, dirty_submodule,
 			      &left, &right, &merge_bases);
 
 	/* We need a valid left and right commit to display a difference */
-- 
2.19.0