Re: [PATCH] pkt-line: do not report packet write errors twice

From

Matheus Tavares <matheus.bernardino@usp.br>

Date

Apr 15, 2021, 20:48 UTC

Message-ID

<20210415204809.1818959-1-matheus.bernardino@usp.br>

In-Reply-To

<xmqqlf9jp9v5.fsf@gitster.g>

On Thu, Apr 15, 2021 at 5:32 PM Junio C Hamano <gitster@pobox.com> wrote:

>
> Matheus Tavares Bernardino <matheus.bernardino@usp.br> writes:
>
> > Nice! :) Maybe we could also avoid the static strings without
> > repeating the literals by making `do_packet_write()` receive a `struct
> > strbuf *err` and save the error message in it? Then the two callers
> > can decide whether to pass it to error() or die() accordingly.
>
> Sorry, but I do not understand what benefit we are trying to gain by
> introducing an extra strbuf (which I assume is used to strbuf_add()
> the error message into).  Wouldn't the caller need two messages and
> flip between <error,error_errno> vs <die,die_errno> pair?

diff --git a/pkt-line.c b/pkt-line.c
index 39c9ca4212..98304ce374 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -195,16 +195,14 @@ int packet_write_fmt_gently(int fd, const char *fmt, ...)
 }

 static int do_packet_write(const int fd_out, const char *buf, size_t size,
-			   int gentle)
+			   struct strbuf *err)
 {
 	char header[4];
 	size_t packet_size;

 	if (size > LARGE_PACKET_DATA_MAX) {
-		if (gentle)
-			return error(_("packet write failed - data exceeds max packet size"));
-		else
-			die(_("packet write failed - data exceeds max packet size"));
+		strbuf_addstr(err, _("packet write failed - data exceeds max packet size"));
+		return -1;
 	}

 	packet_trace(buf, size, 1);
@@ -221,22 +219,28 @@ static int do_packet_write(const int fd_out, const char *buf, size_t size,

 	if (write_in_full(fd_out, header, 4) < 0 ||
 	    write_in_full(fd_out, buf, size) < 0) {
-		if (gentle)
-			return error_errno(_("packet write failed"));
-		else
-			die_errno(_("packet write failed"));
+		strbuf_addf(err, _("packet write failed: %s"), strerror(errno));
+		return -1;
 	}
 	return 0;
 }

 static int packet_write_gently(const int fd_out, const char *buf, size_t size)
 {
-	return do_packet_write(fd_out, buf, size, 1);
+	struct strbuf err = STRBUF_INIT;
+	if (do_packet_write(fd_out, buf, size, &err)) {
+		error("%s", err.buf);
+		strbuf_release(&err);
+		return -1;
+	}
+	return 0;
 }

 void packet_write(int fd_out, const char *buf, size_t size)
 {
-	do_packet_write(fd_out, buf, size, 0);
+	struct strbuf err = STRBUF_INIT;
+	if (do_packet_write(fd_out, buf, size, &err))
+		die("%s", err.buf);
 }

 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)