[Span First #3]: Add active span parenting behaviour and more api scaffolding

[buenaflor]

📜 Description

Span first initiative

💡 Motivation and Context

Part of #3331

💚 How did you test it?

Unit tests

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPii is enabled
• I updated the docs if needed
• All tests passing
• No breaking changes

🔮 Next steps

#skip-changelog

[codecov]

Codecov Report

❌ Patch coverage is 66.15385% with 22 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (feat/span-first@fd7a63c). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
packages/dart/lib/src/protocol/unset_span.dart	0.00%	14 Missing ⚠️
packages/dart/lib/src/protocol/noop_span.dart	33.33%	4 Missing ⚠️
packages/dart/lib/src/hub_adapter.dart	0.00%	2 Missing ⚠️
packages/dart/lib/src/noop_hub.dart	0.00%	1 Missing ⚠️
packages/dart/lib/src/scope.dart	90.90%	1 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##             feat/span-first    #3377   +/-   ##
==================================================
  Coverage                   ?   87.94%           
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  Files                      ?      295           
  Lines                      ?    10069           
  Branches                   ?        0           
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  Hits                       ?     8855           
  Misses                     ?     1214           
  Partials                   ?        0           

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[buenaflor]

cursor review

[cursor]

Bug: Scope clear() does not reset active spans list

The Scope.clear() method, intended to reset the scope, doesn't clear the _activeSpans list. This leaves stale spans, leading to incorrect parenting for new spans and inconsistency with other cleared collection fields.

packages/dart/lib/src/scope.dart#L297-L316

sentry-dart/packages/dart/lib/src/scope.dart

Lines 297 to 316 in 144405e

	/// Resets the Scope to its default state
	Future<void> clear() async {
	clearAttachments();
	level = null;
	span = null;
	_transaction = null;
	_fingerprint = [];
	_tags.clear();
	_extra.clear();
	_eventProcessors.clear();
	_replayId = null;
	propagationContext = PropagationContext();
	_attributes.clear();
	_clearBreadcrumbsSync();
	_setUserSync(null);
	await clearBreadcrumbs();
	await setUser(null);
	}

packages/dart/lib/src/scope.dart#L45-L78

sentry-dart/packages/dart/lib/src/scope.dart

Lines 45 to 78 in 144405e

	final List<Span> _activeSpans = [];
	@visibleForTesting
	List<Span> get activeSpans => List.unmodifiable(_activeSpans);
	/// Returns the currently active span, or `null` if no span is active.
	///
	/// The active span is the most recently set span via [setActiveSpan].
	/// When starting a new span with `active: true` (the default), the new span
	/// becomes a child of this active span.
	@internal
	Span? getActiveSpan() {
	return _activeSpans.lastOrNull;
	}
	/// Sets the given [span] as the currently active span.
	///
	/// Active spans are used to automatically parent new spans.
	/// When a new span is started with `active: true` (the default), it becomes
	/// a child of the currently active span.
	@internal
	void setActiveSpan(Span span) {
	_activeSpans.add(span);
	}
	/// Removes the given [span] from the active spans list.
	///
	/// This should be called when a span ends to remove it from the active
	/// span hierarchy.
	@internal
	void removeActiveSpan(Span span) {
	_activeSpans.remove(span);
	}

 

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