Re: [PATCH 0/2] Set GIT_TRACE2_EVENT_NESTING in test-lib.sh

On Mon, Nov 29, 2021 at 01:40:00PM -0500, Jeff King wrote:

On Mon, Nov 29, 2021 at 01:47:44PM +0000, Derrick Stolee via GitGitGadget wrote:

quoted

As reported by Ævar [1] and diagnosed by Peff in a reply, the default
GIT_TRACE2_EVENT_NESTING is set so low that tests that look for trace2
events can start failing due to an added trace2 region. This can even be
subtle, including the fact that the progress API adds trace2 regions when in
use (which can depend on the verbose output of a test script).

I think this is a good change for fixing the immediate problem of the
test suite failing.

But I have to wonder if this is masking a problem that real users will
see. Aren't we silently discarding trace2 output that could be useful to
somebody debugging or trying to get performance metrics?

I.e., should we be bumping the internal nesting max of 2 to something
higher? If that would that cause problems with existing metrics, should
we be designing new metrics to avoid nesting?

One thing I should have added to the first paragraph: the patches
themselves look fine and I'm OK with this as a band-aid in the short
term.

-Peff