Improve error message when a persisted cursor value cannot be parsed (ConcurrentPerPartitionCursor._set_global_state)

[devin-ai-integration]

Problem

When a persisted cursor state value cannot be parsed with the stream's configured cursor_datetime_formats, ConcurrentPerPartitionCursor._set_global_state() lets the raw ValueError escape during stream construction. The sync dies before any record is read, and the user-facing failure is:

No format in ['%s', '%s'] matching 1698686995.0

Observed in production on a manifest-only source (source-slack, threads stream) where the stored global cursor value carried a fractional epoch ("1698686995.0") while the stream declares cursor_datetime_formats: ["%s"].

Why the current message is poor

• Leaks implementation details (%s format tokens, an internal Python list) with no user-meaningful vocabulary.
• Does not say which stream, which cursor field, or that the value came from saved sync state.
• Offers no remediation (e.g. "refresh/clear the stream state").
• Classified as system_error / failure_origin: source, so it looks like a connector crash rather than an unparseable-state condition.
• Duplicate entries in the format list (['%s', '%s']) because CustomFormatConcurrentStreamStateConverter.__init__ appends datetime_format to input_datetime_formats, which makes the message look nonsensical.

Suggested improvements

1. Wrap the failure in an AirbyteTracedException with a config_error-style (non-system_error) failure type, naming the stream, the cursor field, the offending value, and the accepted formats, plus a remediation hint pointing at refreshing the stream's state.
2. Consider mirroring the tolerance already added for record cursor values in #758 (observe() logs a warning and skips instead of raising) so a single unparseable state value degrades to a warning rather than failing the sync.
3. De-duplicate the formats reported in the message.

References

• Raise site: airbyte_cdk/sources/streams/concurrent/state_converters/datetime_stream_state_converter.py (CustomFormatConcurrentStreamStateConverter.parse_timestamp)
• Call path: ConcurrentPerPartitionCursor._set_initial_state → _set_global_state → parse_value
• Prior art for tolerant handling: fix: do not break on bad cursor value in perpartition cursor #758
• Originating oncall issue: https://github.com/airbytehq/oncall/issues/13342

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[airbyte-support-bot]

Thank you for this detailed report!

This request — improving the error surfaced when a persisted cursor state value cannot be parsed (clearer wording, naming the stream/cursor field, config_error classification, de-duplicated formats, and potentially tolerant handling mirroring #758) — has been logged as an enhancement for the CDK maintainers to review.

In the meantime, if you hit this failure, resetting/clearing the affected stream's state and re-syncing typically resolves the immediate error.

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