Stack parsers use both ? and <anonymous> to denote anonymous functions

[timfish]

Chrome/v8 stack frames use ? to denote anonymous functions but we also use <anonymous> in a few places.

sentry-javascript/packages/utils/src/stacktrace.ts

Line 75 in 78395c6

function: frame.function || '?',

sentry-javascript/packages/utils/src/stacktrace.ts

Line 80 in 78395c6

const defaultFunctionName = '<anonymous>';

[AbhiPrasad]

Hey - you're right that this is kind of a weird inconsistency. @kamilogorek any ideas on why this happens?

[timfish]

If we change this, will it impact fingerprinting?

[AbhiPrasad]

Mostly likely yes - we'll need to understand the grouping impact, but we can get folks more involved there (and run some queries in Sentry to determine possible impact).

[kamilogorek]

@kamilogorek any ideas on why this happens?

Historical reasons. It was called <anonymous> (the same value as anonymous URLs/files in some old browsers) since raven SDK, and we kept it like that. ? comes directly from Tracekit, which was also not changed since the old SDK, as the grouping strategy back then did not group them together afair. Changing this would cause some new issues to pop up.

Now, this will not affect any grouping (at least for one version of it), due to those frames being skipped, see: https://github.com/getsentry/sentry/blob/46d9c2aa672b8abe2e26e52c60e9ffc32eba9c23/src/sentry/grouping/strategies/newstyle.py#L394-L398

Also original references:

sentry-javascript/packages/raven-js/src/raven.js

Line 1122 in 7b664ff

data: {function: orig.name || '<anonymous>'}

sentry-javascript/packages/raven-js/vendor/TraceKit/tracekit.js

Line 29 in 7b664ff

var _slice = [].slice;

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

---

"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[timfish]

I'm going to submit a PR to change everything to ?...

[AbhiPrasad]

yeah that sounds good to me - will be more bundle size efficient. Maybe we should also write this in the developer docs somewhere.

[timfish]

This could potentially be a breaking change since customers might be using RewriteFrames and expecting some specific anonymous frames?

Seems highly unlikely anyone is doing this but worth considering.

[AbhiPrasad]

How about we just backlog for the next major bump then? I don't mind tabling this patch until then since we treat it identically for grouping strategies.

[AbhiPrasad]

resolved with #10732