Refactor exporter API: setExporters + sampler on interface

[loks0n]

Summary

• Replace Span::addExporter() with variadic Span::setExporters(Exporter ...) (replaces the full set; no-arg call clears).
• Move sampling onto the Exporter interface via sample(Span): bool. Built-in exporters take an optional sampler closure as their first constructor argument by convention.
• Sentry is hard-wired to error spans only; a user-supplied sampler is composed (AND) with the error filter, so it can further restrict but not broaden.
• Span::setStorage() now accepts ?Storage — pass null to clear. resetStorage() and reset() removed.
• Adds CHANGELOG.md documenting the 3.0.0 breaking changes.

Test plan

• ./vendor/bin/phpunit — 91 tests pass
• Verify downstream consumers update bootstrap to setExporters(...) and any setStorage(null) swaps for resetStorage()

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR ships the 3.0.0 breaking-change refactor of the exporter API: addExporter / resetExporters / resetStorage / reset are removed in favour of the variadic setExporters(Exporter ...) and a nullable setStorage(?Storage). Sampling responsibility moves from a per-registration closure on Span into an Exporter::sample(Span): bool interface method; built-in exporters accept an optional sampler closure as their first constructor argument.

• Sentry gains robust DSN validation (empty-string guard + component checks for public key, host, and project ID), and its sampler is AND-composed with the built-in error-only filter so a custom sampler can only narrow, never widen, what is sent.
• Span.php's finish loop is simplified: it now iterates a plain array<Exporter> and delegates the sample/export decision entirely to each exporter.
• All 91 tests pass; CHANGELOG and README are fully updated for 3.0.0 consumers.

Confidence Score: 5/5

Safe to merge; the breaking changes are intentional, well-documented, and all tests pass.

The refactor is cleanly scoped: the core Span loop is simpler, the Sentry DSN validation is now robust (empty-string guard + component checks), and the sampling contract is enforced at the interface level. No logic errors were found in the changed paths.

Minor gaps in tests/Exporter/SentryTest.php — Sentry::sample() behavior is not directly tested.

Important Files Changed

Filename	Overview
src/Span/Exporter/Sentry.php	Adds sampler composition (AND with built-in error filter), empty-DSN guard, and component validation; parameter order changed (sampler first, dsn second with '' default and runtime guard). parse_url===false branch may be dead code in PHP 8.x.
src/Span/Span.php	Replaces addExporter/resetExporters/reset/resetStorage with setExporters(variadic) and setStorage(?Storage); sampling loop delegates to Exporter::sample(). Clean refactor.
src/Span/Exporter/Exporter.php	Adds sample(Span): bool to the interface; existing export() doc updated. Straightforward interface extension.
tests/Exporter/SentryTest.php	Adds tests for empty DSN, missing public key, and missing project ID guards. No coverage for sample() returning false for non-error spans or composed-sampler behavior.
tests/SpanTest.php	Migrates all tests to new API (setExporters, setStorage(null)); sampler logic moved into createExporter helper. Coverage is thorough.

_{Reviews (2): Last reviewed commit: "Apply rector suggestions" | Re-trigger Greptile}