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@xxxxxxxxxx/ Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> --- 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
