# Re: \[PATCH 0/2\] Set GIT\_TRACE2\_EVENT\_NESTING in test-lib.sh

- From: Derrick Stolee \<hidden\>
- Date: 2021-11-30 15:34:08 
- List: git
- Page: https://ratatoskr.run/git/2021/11/7913526
- Thread: https://ratatoskr.run/git/2021/11/7913301/t.md

```text
On 11/29/2021 1:40 PM, Jeff King wrote:
> On Mon, Nov 29, 2021 at 01:47:44PM +0000, Derrick Stolee via GitGitGadget wrote:
> 
>> 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 this makes me think about is that we might want to
have items such as trace2_data_intmax() and trace2_data_string()
not be subject to the nesting limit. Only have the nesting apply
to the regions (which nest).

CC'ing Jeff Hostetler for his thoughts on that idea. We will have
a discussion offline to see if the progress regions have started
to cause inconsistencies in our existing telemetry stream of
internal users.

Thanks,
-Stolee
```