From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-11.4 required=3.0 tests=AWL,BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id E32DE1FA1A for ; Tue, 24 Nov 2020 20:19:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730104AbgKXUFb (ORCPT ); Tue, 24 Nov 2020 15:05:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730093AbgKXUFa (ORCPT ); Tue, 24 Nov 2020 15:05:30 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85E6CC0613D6 for ; Tue, 24 Nov 2020 12:05:30 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id 143so12412020pfv.16 for ; Tue, 24 Nov 2020 12:05:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=c9J9ZbvBSlHe9bISBGM21/gzvPVhQUdTS7I6Vvj6poU=; b=kbHSavcnHq7yeJDJC71NhYLLQUrFn4/hI/2r2BMztW4IkAu7YvqUcUs+8FHd1mIeTU K0VTNyPis/I6EDEQYo8jEOPxonLLIqoLb4+vDjncTRNtIfb7s52loysM8wzIu7KocKQ3 rGpr8BxDV1Eyv3MHV7EGicMz58oIjvLyb1vi6opTbw5MmWJwvE+/vQfFL8le7NkNOzsK PUAR72LlmWj5VTUYaSoeotrisS0sHDiAfE9SmSiKsSAdjYsm07JVPWkox+H2JOSWWoO3 FqlE0tG0MIXWEK7njHBQDJIw3D5oat/eQludrU/yZh1nyOTvCq1ceG3M6Yn3fHY1/kYk diTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=c9J9ZbvBSlHe9bISBGM21/gzvPVhQUdTS7I6Vvj6poU=; b=IsHXNIEYs8i2jMhkJOv9eTzNkJHTy4Co823YnNU0Fimr42RQQWwJDQg51/VXcLFxGk Ek05CV/jqcrAOcWVzNw4EPqRUm5XT8hJLwsbLmOANpJ0XQWc+jAWwxeROqL8luXjz8Ce 6JsP87kvfbT9g/G5fFjCgqlWmUYNw88L2xVKrk5nK8BZAiqfAHgYmLeN2JJW9tuCR1bI cQduFGlMehWaqH7a039+BvExmUEQnyTk/STedQkOlKoNYts9eTfTZyWhQQYgu/I0w27J el1oHuqibY6jezvFzxR8CiwEoWTox5ibuqs/uvOs1D5P+HVd+swqYGH7nRyL7ZvbI0vw 9Low== X-Gm-Message-State: AOAM532a4EeYY+/AIS9p/rvsLc4eyLeStddv36yvBn/XoXPauK4xL1DD HayenB50kGOj8SheDNWjB38Z+0tdp5BiPPDXcd0K4hoJpgZ5RRxesObvFUwxvvsxeuG25BAMqpG 8JYoelGqE5MVW0l7umbSOuZSwtIiKpZ2sxIAXp7Oz/QVGQSTN+afLphAMABi/EbaXxdZ/0MZjtd lP X-Google-Smtp-Source: ABdhPJzsqKPH09w7Pn7m3uHfp1dIGzKoCG0x9S1lLOlG7M93wqBjdoDBF4z994o5FO3Uf6eJ6gy0yc1vN4enYvXGyRqr Sender: "jonathantanmy via sendgmr" X-Received: from twelve4.c.googlers.com ([fda3:e722:ac3:10:24:72f4:c0a8:437a]) (user=jonathantanmy job=sendgmr) by 2002:a17:90a:f406:: with SMTP id ch6mr288677pjb.134.1606248329938; Tue, 24 Nov 2020 12:05:29 -0800 (PST) Date: Tue, 24 Nov 2020 12:05:27 -0800 In-Reply-To: <20201123190412.101265-1-jonathantanmy@google.com> Message-Id: <20201124200527.890563-1-jonathantanmy@google.com> Mime-Version: 1.0 References: <20201123190412.101265-1-jonathantanmy@google.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH v3] usage: add trace2 entry upon warning() From: Jonathan Tan To: git@vger.kernel.org Cc: Jonathan Tan , gitster@pobox.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org 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 --- Thanks, Junio. That comment looks good. Here is the version with Junio's suggested comment included, for everyone's reference. --- Documentation/technical/api-trace2.txt | 2 +- trace2.h | 5 +++++ usage.c | 6 ++++++ 3 files changed, 12 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/trace2.h b/trace2.h index b18bc5529c..2b5c5c4ba0 100644 --- a/trace2.h +++ b/trace2.h @@ -116,6 +116,11 @@ int trace2_cmd_exit_fl(const char *file, int line, int code); * Emit an 'error' event. * * Write an error message to the TRACE2 targets. + * + * Note that the "va_list ap" the caller has is not touched, because + * it is fed to each of the TRACE2 targets, which must use va_copy() + * and use va_end() on the copy. The caller can still use ap it uses + * to call this function and and call va_end() on it when it is done. */ void trace2_cmd_error_va_fl(const char *file, int line, const char *fmt, va_list ap); 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