supabase / supabase-flutter / 35886870210

94%

Build Type

push

github

Committed by web-flow

Commit Message

feat(supabase): warn when trace propagation attaches no headers (#1872)

## What

Every failure mode of trace propagation was silent, so a misconfigured
setup looked exactly like a working one until someone went looking in
the Supabase logs.

Two warnings, each logged once per client through `clientLogger`:

- propagation enabled with no `traceContextProvider`
- the provider returned a `traceparent` that is not well-formed

A value shaped like a `sentry-trace` header, three parts rather than
four, names `formatAsW3CHeader` in the warning, the way supabase-js
names `propagateTraceparent` when it sees a Sentry propagator.

A malformed `traceparent` is now **dropped** rather than sent. It
correlates with nothing on the server, so forwarding it only hid the
mistake. This is a deliberate divergence from supabase-js, which
forwards: there the header comes from the OpenTelemetry API and is
well-formed by construction, whereas here it comes from application
code.

## Scope

No public API change. `isSampledTraceparent` now assumes a validated
header, since the caller checks first.

---

Part 3 of a stack of 3, based on #1871:

1. #1870, sampling
2. #1871, `TraceContext` constructors
3. **This PR**, diagnostics

https://linear.app/supabase/issue/SDK-1937

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Malformed trace headers are omitted from outgoing requests instead of
being propagated, and a warning is logged when one is encountered. Valid
headers from future traceparent versions continue to be supported.
* A warning is logged when trace propagation is enabled without a trace
context provider.
* **Documentation**
* Clarified that malformed trace headers are dropped with a warning
rather than propagated.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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34 existing lines in 3 files now uncovered.

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