[PATCH v7 18/40] builtin/apply: make build_fake_ancestor() return -1 on error

[Christian Couder <christian.couder@gmail.com>]

To libify `git apply` functionality we have to signal errors to the
caller instead of die()ing.

To do that in a compatible manner with the rest of the error handling
in "builtin/apply.c", build_fake_ancestor() should return -1 instead
of calling die().

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 builtin/apply.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index 429fddd..e74b068 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -3889,11 +3889,12 @@ static int preimage_sha1_in_gitlink_patch(struct patch *p, unsigned char sha1[20
 }
 
 /* Build an index that contains the just the files needed for a 3way merge */
-static void build_fake_ancestor(struct patch *list, const char *filename)
+static int build_fake_ancestor(struct patch *list, const char *filename)
 {
 	struct patch *patch;
 	struct index_state result = { NULL };
 	static struct lock_file lock;
+	int res;
 
 	/* Once we start supporting the reverse patch, it may be
 	 * worth showing the new sha1 prefix, but until then...
@@ -3911,31 +3912,38 @@ static void build_fake_ancestor(struct patch *list, const char *filename)
 			if (!preimage_sha1_in_gitlink_patch(patch, sha1))
 				; /* ok, the textual part looks sane */
 			else
-				die("sha1 information is lacking or useless for submodule %s",
-				    name);
+				return error("sha1 information is lacking or "
+					     "useless for submodule %s", name);
 		} else if (!get_sha1_blob(patch->old_sha1_prefix, sha1)) {
 			; /* ok */
 		} else if (!patch->lines_added && !patch->lines_deleted) {
 			/* mode-only change: update the current */
 			if (get_current_sha1(patch->old_name, sha1))
-				die("mode change for %s, which is not "
-				    "in current HEAD", name);
+				return error("mode change for %s, which is not "
+					     "in current HEAD", name);
 		} else
-			die("sha1 information is lacking or useless "
-			    "(%s).", name);
+			return error("sha1 information is lacking or useless "
+				     "(%s).", name);
 
 		ce = make_cache_entry(patch->old_mode, sha1, name, 0, 0);
 		if (!ce)
-			die(_("make_cache_entry failed for path '%s'"), name);
-		if (add_index_entry(&result, ce, ADD_CACHE_OK_TO_ADD))
-			die ("Could not add %s to temporary index", name);
+			return error(_("make_cache_entry failed for path '%s'"),
+				     name);
+		if (add_index_entry(&result, ce, ADD_CACHE_OK_TO_ADD)) {
+			free(ce);
+			return error("Could not add %s to temporary index",
+				     name);
+		}
 	}
 
 	hold_lock_file_for_update(&lock, filename, LOCK_DIE_ON_ERROR);
-	if (write_locked_index(&result, &lock, COMMIT_LOCK))
-		die ("Could not write temporary index to %s", filename);
-
+	res = write_locked_index(&result, &lock, COMMIT_LOCK);
 	discard_index(&result);
+
+	if (res)
+		return error("Could not write temporary index to %s", filename);
+
+	return 0;
 }
 
 static void stat_patch_list(struct apply_state *state, struct patch *patch)
@@ -4476,8 +4484,11 @@ static int apply_patch(struct apply_state *state,
 		goto end;
 	}
 
-	if (state->fake_ancestor)
-		build_fake_ancestor(list, state->fake_ancestor);
+	if (state->fake_ancestor &&
+	    build_fake_ancestor(list, state->fake_ancestor)) {
+		res = -1;
+		goto end;
+	}
 
 	if (state->diffstat)
 		stat_patch_list(state, list);
-- 
2.9.0.rc2.411.g3e2ca28