convert: quote filter names in error messages

Git filter driver commands with spaces (e.g. `filter.sh foo`) are hard
to read in error messages. Quote them to improve the readability.

Signed-off-by: Lars Schneider <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: larsxschneider

convert.c

@@ -412,7 +412,7 @@ static int filter_buffer_or_fd(int in, int out, void *data)
 	child_process.out = out;
 
 	if (start_command(&child_process))
-		return error("cannot fork to run external filter %s", params->cmd);
+		return error("cannot fork to run external filter '%s'", params->cmd);
 
 	sigchain_push(SIGPIPE, SIG_IGN);
 
@@ -430,13 +430,13 @@ static int filter_buffer_or_fd(int in, int out, void *data)
 	if (close(child_process.in))
 		write_err = 1;
 	if (write_err)
-		error("cannot feed the input to external filter %s", params->cmd);
+		error("cannot feed the input to external filter '%s'", params->cmd);
 
 	sigchain_pop(SIGPIPE);
 
 	status = finish_command(&child_process);
 	if (status)
-		error("external filter %s failed %d", params->cmd, status);
+		error("external filter '%s' failed %d", params->cmd, status);
 
 	strbuf_release(&cmd);
 	return (write_err || status);
@@ -477,15 +477,15 @@ static int apply_filter(const char *path, const char *src, size_t len, int fd,
 		return 0;	/* error was already reported */
 
 	if (strbuf_read(&nbuf, async.out, len) < 0) {
-		error("read from external filter %s failed", cmd);
+		error("read from external filter '%s' failed", cmd);
 		ret = 0;
 	}
 	if (close(async.out)) {
-		error("read from external filter %s failed", cmd);
+		error("read from external filter '%s' failed", cmd);
 		ret = 0;
 	}
 	if (finish_async(&async)) {
-		error("external filter %s failed", cmd);
+		error("external filter '%s' failed", cmd);
 		ret = 0;
 	}