[jespersandnielsen]

Add Sentry.add_feature_flag and Scope#add_feature_flag to record boolean flag evaluations. Flags are kept in a 100-entry LRU buffer on the scope, attached to error events as contexts.flags.values (not transactions), and recorded on the active span as flag.evaluation.* data (max 10 per span).

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Description

Describe your changes:

• resolves: Support for tracking feature flags #2559

[jespersandnielsen]

@sl0thentr0py What is needed in order to merge this PR?

[sl0thentr0py]

thx @jespersandnielsen, I'll make some small changes and then merge it

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Span flags skip updates at cap

Medium Severity

Once a span already holds 10 feature flags, set_flag rejects every write, including a new result for a name that is already stored. The scope buffer still keeps the latest evaluation, so error events and the active span can disagree on the same flag.evaluation.* value after a re-evaluation.

 

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[sl0thentr0py]

matches python behavior 🤷 agree that the logic is a bit whatever