fix: guard against double-unsubscribe removing wrong subscriber in cache.ts

[tomohiro86]

Summary

Fixes #4251

• subscribe in src/_internal/utils/cache.ts returned () => subs.splice(subs.indexOf(callback), 1)
• When the unsubscribe function was called a second time, indexOf returned -1 and splice(-1, 1) silently removed the last subscriber in the array instead of being a no-op
• Fix adds an index >= 0 guard and uses the same O(1) swap-and-pop pattern already present in src/_internal/utils/subscribe-key.ts

Changes

• src/_internal/utils/cache.ts: align the unsubscribe logic with subscribeCallback in subscribe-key.ts

Test plan

• All existing tests pass (pnpm test: 360 passed, 5 skipped)
• TypeScript type check passes (tsc --noEmit)
• Build succeeds (pnpm build)

[Copilot]

Pull request overview

Fixes an internal cache subscription bug where calling the returned unsubscribe function more than once could remove the wrong subscriber (due to splice(-1, 1) when indexOf returns -1). This aligns the unsubscribe behavior with the existing subscribeCallback utility’s guarded swap-and-pop removal pattern.

Changes:

• Make unsubscribe idempotent by guarding against indexOf returning -1.
• Replace splice removal with an O(1) swap-and-pop removal approach (consistent with subscribe-key.ts).

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[promer94]

@tomohiro86 Could you signed the commit ?

[tomohiro86]

@promer94
Is this okay?

[promer94]

Sorry I did not give you the correct context.

@tomohiro86 You can follow this documention https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits to sign the commit.

[tomohiro86]

@promer94
I have committed with a signing.

[promer94]

@tomohiro86 It’s required that you have to sign all your commits. You might need to rebase your current commits. Coding agent can help you with that.

[tomohiro86]

Thanks for the heads-up! I've rebased and signed the commit — GitHub now shows it as verified.