fix: preserve empty-string text parts in A2A converter#5343
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voidborne-d wants to merge 1 commit intogoogle:mainfrom
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fix: preserve empty-string text parts in A2A converter#5343voidborne-d wants to merge 1 commit intogoogle:mainfrom
voidborne-d wants to merge 1 commit intogoogle:mainfrom
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Part(text='') is valid — it is produced by code_execution_utils.py when code execution returns None, and by interactions_utils.py when the Interactions API returns None text. Gemini 2.5 Flash thinking mode also emits empty text parts. The truthiness check `if part.text:` treats '' as falsy, causing the converter to skip the part entirely. When all parts in a response are empty the A2A message ends up with zero parts and the client sees "broken thinking" with no content. Change the check to `if part.text is not None:` so that empty strings are correctly wrapped as TextPart while None is still skipped. Add a regression test for the empty-string case. Fixes google#5341
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Summary
Fixes #5341 —
convert_genai_part_to_a2a_part()dropsPart(text='')because the truthiness checkif part.text:treats empty strings as falsy.Root Cause
Part(text='')is valid and is produced in at least two places in the ADK:code_executors/code_execution_utils.py— when code execution completes withNoneoutputmodels/interactions_utils.py— when the Interactions API returnsNonetext contentGemini 2.5 Flash (thinking mode) also emits empty text parts.
When the converter drops all parts the A2A message ends up with zero parts and the client sees "broken thinking" with no content.
Fix
Change line 182 from
if part.text:toif part.text is not None:so that empty strings are correctly wrapped asTextPartwhileNoneis still skipped.Test
Added
test_convert_empty_text_part— verifies thatPart(text='')produces a validTextPart(text='')instead of returningNone.