fix(odin): Fix oversize metadata field truncation issue

[vikramlc-cognite]

Summary

Fixes truncated custom-action result messages so the explanation of why metadata fields were dropped always survives truncation, instead of being pushed off the end by an unbounded list of field names.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that changes existing behavior)
• Refactor (no functional change)
• Documentation update
• Chore / tooling / CI

What changed

• cognite/extractorutils/unstable/core/base.py — _handle_custom_action success path: reordered the oversized-metadata message so the fixed explanation ("N metadata field(s) exceeded the byte limit and were dropped") comes before the unbounded field-name list, and reports a count instead of only names.
• Same reordering applied to the parallel ActionError branch's message.
• tests/test_unstable/test_action_dispatch.py — added regression assertions to the many-fields test confirming "exceeded"/"dropped" survive truncation.

Why it changed

• Related issue: EDG-825
• Related docs / discussion: PR fix(odin): Fixed cancelling an in-flight action #572 review comment discussion (discussion_r3911633979)

truncate_message() truncates from the end at 1000 chars. With the old ordering, a large enough number of oversized fields (e.g. 45, as in the existing regression test) pushed the trailing explanation entirely off the message, leaving only a cut-off list of field names with no indication of what happened or why.

What to focus on during review

• The ActionError branch still has str(e) (itself unbounded) ahead of the reordered explanation — reordering doesn't fully protect against a pathologically long ActionError message on its own; that's a separate, pre-existing concern out of scope here.
• Message wording change is user-facing (result_message surfaced to Odin/callers) — confirm no downstream parsing depends on the old phrasing.

Test evidence

• python -m pytest tests/test_unstable/test_action_dispatch.py -q → 37 passed.
• python -m pytest tests/test_unstable/ -q → 248 passed / 1 failed / 48 errors, identical to the pre-change baseline (verified via git stash) — failures are pre-existing KeyError: 'COGNITE...' env-fixture issues unrelated to this change.

Risks and unknowns

• ActionError.__str__() can itself exceed 1000 chars, in which case the explanation still gets truncated away regardless of ordering — not addressed here, flagged as a possible follow-up.

Rollout and rollback

• No config/migration changes; pure message-formatting fix. Revert the commit to roll back.

Checklist

• Self-reviewed the diff
• Tests added or updated
• Docs updated (N/A — no user-facing docs describe this message format)
• No secrets, credentials, or PII committed
• Breaking changes called out above and communicated to affected teams (N/A — non-breaking)

[vikramlc-cognite]

/gemini review

[gemini-code-assist]

Code Review

This pull request improves the result messages when custom action metadata fields exceed the byte limit by including the count of oversized fields and appending the list of dropped fields to the end of the message. It also adds corresponding regression tests. The reviewer suggested reordering the error message format to ensure the metadata dropped warning survives truncation even if the exception message is extremely long.

[gemini-code-assist]

Code Review

This pull request improves the reporting of oversized metadata fields in custom actions by including the count of oversized fields and appending the list of fields to the end of the message. It also adds corresponding regression tests. The reviewer pointed out that if the exception message is extremely long, the explanation of dropped metadata fields could be lost during truncation, and suggested truncating the exception message to a safe limit first.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.09%. Comparing base (e5cf9ab) to head (8d1e65d).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #576   +/-   ##
=======================================
  Coverage   84.09%   84.09%           
=======================================
  Files          46       46           
  Lines        4709     4709           
=======================================
  Hits         3960     3960           
  Misses        749      749           

Files with missing lines	Coverage Δ
cognite/extractorutils/unstable/core/base.py	86.90% <ø> (ø)

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[Khyat-Cognite]

/gemini review

[gemini-code-assist]

Code Review

This pull request improves the formatting of error and result messages when custom action metadata fields exceed the size limit. By placing the count of oversized fields and the explanation of the limit violation before the list of dropped fields, the explanation is guaranteed to survive message truncation. Additionally, regression tests have been added to verify that key terms like 'exceeded' and 'dropped' remain in the truncated messages. No review comments were provided, so there is no additional feedback.

[Khyat-Cognite]

🦄 -- LGTM ^^