[PATCH v7 04/40] builtin/apply: make find_header() return -1 instead of die()ing

[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, find_header() should return -1 instead of calling
die().

Unfortunately find_header() already returns -1 when no header is found,
so let's make it return -2 instead in this case.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 builtin/apply.c       | 33 ++++++++++++++++++++++-----------
 t/t4254-am-corrupt.sh |  2 +-
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index 2ff8450..630c01c 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -1419,6 +1419,14 @@ static int parse_fragment_header(const char *line, int len, struct fragment *fra
 	return offset;
 }
 
+/*
+ * Find file diff header
+ *
+ * Returns:
+ *  -1 in case of error
+ *  -2 if no header was found
+ *   the size of the header in bytes (called "offset") otherwise
+ */
 static int find_header(struct apply_state *state,
 		       const char *line,
 		       unsigned long size,
@@ -1452,8 +1460,8 @@ static int find_header(struct apply_state *state,
 			struct fragment dummy;
 			if (parse_fragment_header(line, len, &dummy) < 0)
 				continue;
-			die(_("patch fragment without header at line %d: %.*s"),
-			    state->linenr, (int)len-1, line);
+			return error(_("patch fragment without header at line %d: %.*s"),
+				     state->linenr, (int)len-1, line);
 		}
 
 		if (size < len + 6)
@@ -1469,18 +1477,18 @@ static int find_header(struct apply_state *state,
 				continue;
 			if (!patch->old_name && !patch->new_name) {
 				if (!patch->def_name)
-					die(Q_("git diff header lacks filename information when removing "
-					       "%d leading pathname component (line %d)",
-					       "git diff header lacks filename information when removing "
-					       "%d leading pathname components (line %d)",
-					       state->p_value),
-					    state->p_value, state->linenr);
+					return error(Q_("git diff header lacks filename information when removing "
+							"%d leading pathname component (line %d)",
+							"git diff header lacks filename information when removing "
+							"%d leading pathname components (line %d)",
+							state->p_value),
+						     state->p_value, state->linenr);
 				patch->old_name = xstrdup(patch->def_name);
 				patch->new_name = xstrdup(patch->def_name);
 			}
 			if (!patch->is_delete && !patch->new_name)
-				die("git diff header lacks filename information "
-				    "(line %d)", state->linenr);
+				return error("git diff header lacks filename information "
+					     "(line %d)", state->linenr);
 			patch->is_toplevel_relative = 1;
 			*hdrsize = git_hdr_len;
 			return offset;
@@ -1505,7 +1513,7 @@ static int find_header(struct apply_state *state,
 		state->linenr += 2;
 		return offset;
 	}
-	return -1;
+	return -2;
 }
 
 static void record_ws_error(struct apply_state *state,
@@ -1996,6 +2004,9 @@ static int parse_chunk(struct apply_state *state, char *buffer, unsigned long si
 	int hdrsize, patchsize;
 	int offset = find_header(state, buffer, size, &hdrsize, patch);
 
+	if (offset == -1)
+		exit(1);
+
 	if (offset < 0)
 		return offset;
 
diff --git a/t/t4254-am-corrupt.sh b/t/t4254-am-corrupt.sh
index 85716dd..9bd7dd2 100755
--- a/t/t4254-am-corrupt.sh
+++ b/t/t4254-am-corrupt.sh
@@ -29,7 +29,7 @@ test_expect_success 'try to apply corrupted patch' '
 '
 
 test_expect_success 'compare diagnostic; ensure file is still here' '
-	echo "fatal: git diff header lacks filename information (line 4)" >expected &&
+	echo "error: git diff header lacks filename information (line 4)" >expected &&
 	test_path_is_file f &&
 	test_cmp expected actual
 '
-- 
2.9.0.rc2.411.g3e2ca28