ref(core): Rewrite logger to avoid side effects

[mydea]

This has bugged me often already, and I looked into it again nudged by #16846. Today the logger export from core has a side effect and reads from the global. This is a bit weird...

This PR rewrites this to instead only keep the enabled flag on the carrier. The logger itself is a "normal" method that just looks at the carrier to see if logging is enabled or not.

[github-actions]

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	23.86 kB	+0.19%	+43 B 🔺
@sentry/browser - with treeshaking flags	22.49 kB	-0.22%	-49 B 🔽
@sentry/browser (incl. Tracing)	39.7 kB	+0.07%	+27 B 🔺
@sentry/browser (incl. Tracing, Replay)	77.89 kB	+0.12%	+92 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	67.73 kB	+0.01%	+1 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)	82.57 kB	+0.1%	+82 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)	94.71 kB	+0.12%	+107 B 🔺
@sentry/browser (incl. Feedback)	40.54 kB	+0.11%	+44 B 🔺
@sentry/browser (incl. sendFeedback)	28.53 kB	+0.11%	+31 B 🔺
@sentry/browser (incl. FeedbackAsync)	33.43 kB	+0.13%	+42 B 🔺
@sentry/react	25.6 kB	-0.01%	-2 B 🔽
@sentry/react (incl. Tracing)	41.66 kB	+0.01%	+3 B 🔺
@sentry/vue	28.27 kB	+0.02%	+5 B 🔺
@sentry/vue (incl. Tracing)	41.48 kB	+0.02%	+7 B 🔺
@sentry/svelte	23.87 kB	+0.19%	+45 B 🔺
CDN Bundle	25.24 kB	-0.51%	-128 B 🔽
CDN Bundle (incl. Tracing)	39.47 kB	-0.41%	-161 B 🔽
CDN Bundle (incl. Tracing, Replay)	75.56 kB	-0.01%	-5 B 🔽
CDN Bundle (incl. Tracing, Replay, Feedback)	81.02 kB	-0.01%	-3 B 🔽
CDN Bundle - uncompressed	73.67 kB	-0.56%	-410 B 🔽
CDN Bundle (incl. Tracing) - uncompressed	117.24 kB	-0.39%	-458 B 🔽
CDN Bundle (incl. Tracing, Replay) - uncompressed	231.74 kB	+0.05%	+113 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	244.55 kB	+0.05%	+113 B 🔺
@sentry/nextjs (client)	43.3 kB	-	-
@sentry/sveltekit (client)	40.16 kB	+0.07%	+28 B 🔺
@sentry/node	167.59 kB	-0.17%	-278 B 🔽
@sentry/node - without tracing	100.3 kB	-0.29%	-288 B 🔽
@sentry/aws-serverless	128.43 kB	-0.21%	-266 B 🔽

View base workflow run

[AbhiPrasad]

I wonder if we should rename logger to sentryLogger as well.

This would allow us to export the sentry logging logger from @sentry/core as well.

[cursor]

Bug: Logger Singleton Issue in Non-DEBUG Builds

In non-DEBUG builds, _getLoggerSettings() incorrectly returns a new { enabled: false } object on each call instead of using the global singleton. This breaks the logger's state management: enable() and disable() become no-ops as they modify a discarded temporary object, and isEnabled() always returns false. This behavior differs from the previous implementation, which correctly maintained the logger's enabled state even when logging was disabled.

packages/core/src/utils/logger.ts#L128-L135

sentry-javascript/packages/core/src/utils/logger.ts

Lines 128 to 135 in c82b4e8

	function _getLoggerSettings(): { enabled: boolean } {
	if (!DEBUG_BUILD) {
	return { enabled: false };
	}
	return getGlobalSingleton('loggerSettings', () => ({ enabled: false }));
	}

packages/core/src/utils/logger.ts#L76-L87

sentry-javascript/packages/core/src/utils/logger.ts

Lines 76 to 87 in c82b4e8

	function enable(): void {
	_getLoggerSettings().enabled = true;
	}
	function disable(): void {
	_getLoggerSettings().enabled = false;
	}
	function isEnabled(): boolean {
	return _getLoggerSettings().enabled;
	}

Fix in Cursor • Fix in Web

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[AbhiPrasad]

Going to merge this in so I can work on #16901