git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Jonathan Tan <jonathantanmy@google.com>
To: git@vger.kernel.org
Cc: Jonathan Tan <jonathantanmy@google.com>, git@jeffhostetler.com
Subject: [RFC PATCH v2] usage: add trace2 entry upon warning()
Date: Mon, 23 Nov 2020 12:45:22 -0800	[thread overview]
Message-ID: <20201123204522.675836-1-jonathantanmy@google.com> (raw)
In-Reply-To: <20201123190412.101265-1-jonathantanmy@google.com>

Emit a trace2 error event whenever warning() is called, just like when
die(), error(), or usage() is called.

This helps debugging issues that would trigger warnings but not errors.
In particular, this might have helped debugging an issue I encountered
with commit graphs at $DAYJOB [1].

There is a tradeoff between including potentially relevant messages and
cluttering up the trace output produced. I think that warning() messages
should be included in traces, because by its nature, Git is used over
multiple invocations of the Git tool, and a failure (currently traced)
in a Git invocation might be caused by an unexpected interaction in a
previous Git invocation that only has a warning (currently untraced) as
a symptom - as is the case in [1].

[1] https://lore.kernel.org/git/20200629220744.1054093-1-jonathantanmy@google.com/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
Whoops...I ran a compile for the first version but I sent the email out
before looking at the results. The first version had a compile error,
but this one should be fine.
---
 Documentation/technical/api-trace2.txt | 2 +-
 usage.c                                | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt
index 6b6085585d..c65ffafc48 100644
--- a/Documentation/technical/api-trace2.txt
+++ b/Documentation/technical/api-trace2.txt
@@ -466,7 +466,7 @@ completed.)
 
 `"error"`::
 	This event is emitted when one of the `error()`, `die()`,
-	or `usage()` functions are called.
+	`warning()`, or `usage()` functions are called.
 +
 ------------
 {
diff --git a/usage.c b/usage.c
index 06665823a2..1868a24f7a 100644
--- a/usage.c
+++ b/usage.c
@@ -81,6 +81,12 @@ static void error_builtin(const char *err, va_list params)
 
 static void warn_builtin(const char *warn, va_list params)
 {
+	/*
+	 * We call this trace2 function first and expect it to va_copy 'params'
+	 * before using it (because an 'ap' can only be walked once).
+	 */
+	trace2_cmd_error_va(warn, params);
+
 	vreportf("warning: ", warn, params);
 }
 
-- 
2.29.2.454.gaff20da3a2-goog


  reply	other threads:[~2020-11-23 20:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-23 19:04 [RFC PATCH] usage: add trace2 entry upon warning() Jonathan Tan
2020-11-23 20:45 ` Jonathan Tan [this message]
2020-11-23 22:30   ` [RFC PATCH v2] " Junio C Hamano
2020-11-24 20:05 ` [PATCH v3] " Jonathan Tan
2020-11-24 22:15   ` Junio C Hamano
2020-11-30 16:16 ` [RFC PATCH] " Jeff Hostetler

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201123204522.675836-1-jonathantanmy@google.com \
    --to=jonathantanmy@google.com \
    --cc=git@jeffhostetler.com \
    --cc=git@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).