fix(core): implement ChatPromptTemplate.save by delegating to BasePromptTemplate

[antznette1]

• Implemented
  ChatPromptTemplate.save by delegating to BasePromptTemplate.save, matching existing patterns in other prompt templates, enabling serialization to JSON/YAML consistent with other prompt templates.

• Aligns
  ChatPromptTemplate with FewShotPromptTemplate’s pattern.

• Changes
  libs/core/langchain_core/prompts/chat.py

  • Implemented save(self, file_path) to call super().save(file_path).

• Behavior

  • No breaking changes.
  • New behavior:
    ChatPromptTemplate.save("path/to/file.yaml") now works as expected.

• Test

  • “Added a roundtrip unit test for ChatPromptTemplate.save to JSON/YAML.”

• Issue
  Fixes ChatPromptTemplate save() not implemented #32637

[codspeed-hq]

CodSpeed Performance Report

Merging #33852 will not alter performance

_{Comparing antznette1:fix/chatprompttemplate-save-32637 (c9700da) with master (d40e340)}

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

✅ 13 untouched
⏩ 21 skipped¹

Footnotes

1. 21 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩