Race condition causes span loss when buffer is at flush threshold (sentry_sdk/_span_batcher.py:19)

When MAX_BEFORE_FLUSH (1000) equals MAX_BEFORE_DROP (1000), a race condition exists where spans are unnecessarily dropped. After the 1000th span triggers a flush and releases the lock, subsequent add() calls can acquire the lock before the flush thread clears the buffer, seeing size >= MAX_BEFORE_DROP and dropping spans. This results in data loss during high-throughput scenarios.

Async Redis spans are not closed when exceptions occur (sentry_sdk/integrations/redis/_async_common.py:135)

In _sentry_execute_command, spans are created via __enter__() but __exit__() is called outside of a try/finally block. If old_execute_command raises an exception, the db_span and cache_span will never be closed, causing span leaks. The sync version in _sync_common.py correctly wraps this in a try/finally block (lines 141-151).

AttributeError when legacy Span is on scope during streaming mode (sentry_sdk/scope.py:1249)

At line 1249, parent_span is assigned from self.span or self.get_current_scope().span, which can be a legacy Span (from sentry_sdk.tracing). However, at line 1284, the code accesses parent_span.segment, an attribute that only exists on StreamedSpan, not on the legacy Span class. If streaming mode is enabled but a legacy Span ends up on the scope (e.g., from a third-party integration or mixed code), this will cause an AttributeError: 'Span' object has no attribute 'segment'.

Span silently dropped when end() called without start() (sentry_sdk/traces.py:341)

When span.end() is called without first calling span.start() or using the context manager, the _context_manager_state attribute is not initialized. The code at line 342 attempts to unpack this attribute, and the resulting AttributeError is swallowed by capture_internal_exceptions(). The span is silently dropped without any warning to the user, and the scope's span reference is not restored.

Identified by Warden find-bugs