fix(sdk): improve force flush logic

[grvmishra788]

Description

Fixes #4631

Before: SynchronousMultiSpanProcessor.force_flush and SynchronousMultiLogRecordProcessor.force_flush used if not sp.force_flush(...): return False, which stopped iterating through processors as soon as any one returned a falsy value. This meant that a processor returning None would cause all subsequent processors to be silently skipped. The concurrent variants had the same truthiness check on results, incorrectly treating None as failure.

After: All multi-processor force_flush implementations now:

• Continue calling every registered processor regardless of individual return values (timeout-based early exit is preserved).
• Use is False instead of not result to distinguish between an explicit False (timeout exceeded) and None (not implemented / nothing to flush).
• SpanProcessor.force_flush returns True by default instead of implicitly returning None.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Unit tests (SDK)
• Typecheck
• Lint
• Pre-commit
• Spellcheck

Does This PR Require a Contrib Repo Change?

• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added

[grvmishra788]

Hi @alexmojaki! Could you please review this one? TIA.

[MikeGoldsmith]

Looks good, thanks @grvmishra788

[alexmojaki]

Thanks!

[aabmass]

@DylanRussell can you take a look?

[Copilot]

Pull request overview

Fixes an SDK bug where multi-processor force_flush() could incorrectly stop iterating when a processor returned None (or other falsy values), causing later processors to be skipped. This aligns behavior with the documented “only fail on explicit timeout/False” semantics and ensures all registered processors are invoked (unless the overall timeout is exceeded).

Changes:

• Make SpanProcessor.force_flush() return True by default (instead of implicitly None).
• Update synchronous and concurrent multi span/log processor force_flush() implementations to treat only an explicit False as failure and to continue invoking all processors.
• Add unit tests covering None and False return values for both synchronous and concurrent multi-processor variants; add a changelog entry.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
opentelemetry-sdk/src/opentelemetry/sdk/trace/init.py	Fixes multi span processor force_flush() logic to distinguish None vs explicit False, and makes base SpanProcessor.force_flush() return True.
opentelemetry-sdk/src/opentelemetry/sdk/_logs/_internal/init.py	Fixes multi log record processor force_flush() logic to distinguish None vs explicit False.
opentelemetry-sdk/tests/trace/test_span_processor.py	Adds coverage ensuring None does not short-circuit and that all span processors are still invoked.
opentelemetry-sdk/tests/logs/test_multi_log_processor.py	Adds coverage for None/False return handling in synchronous and concurrent multi log record processors.
CHANGELOG.md	Documents the bug fix in the Unreleased section.

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