Anchor service metadata patterns so foreach paths do not prefix-match

[winklemad]

PR Type

• Bug fix

Summary

Handles the OSS service-provider side of #3341. Task.parent_tasks and
Task.child_tasks pass foreach execution-path patterns to the metadata
service, whose regex matching is unanchored. An exact path such as middle:1
could therefore also select middle:10 and middle:11.

The local-provider side is handled separately by #3342.

Root Cause

ServiceMetadataProvider.filter_tasks_by_metadata forwarded the raw pattern
to the metadata service:

query_params["pattern"] = pattern

The service applies that pattern as an unanchored regex search.

Fix

Wrap the forwarded pattern in full-string anchors:

query_params["pattern"] = "^(?:%s)$" % pattern

This makes middle:1 exact while preserving the descendant pattern
middle:1,.*. The existing .* match-all case remains short-circuited and
sends no pattern.

Tests

test/unit/test_service_metadata_provider.py covers:

• exact path anchoring;
• descendant pattern anchoring;
• the match-all short circuit.

Run with:

python -m pytest test/unit/test_service_metadata_provider.py -q

Non-Goals

• The local metadata provider and its tests are handled by Anchor metadata pattern matching so foreach paths do not prefix-match #3342.
• No metadata-service repository change is required; anchoring happens at the
  OSS client boundary.

AI Tool Usage

• AI tools were used.

Tool disclosed by the author: Claude Code, used to help implement the original
change and tests. The service-only rescope retains that implementation.

[greptile-apps]

Greptile Summary

The PR anchors metadata-service task-filter patterns so exact foreach execution paths no longer select tasks whose indices merely share a prefix.

• Wraps non-match-all service patterns with full-string regex anchors.
• Preserves the existing match-all behavior by omitting the pattern query parameter.
• Adds unit coverage for exact, descendant, and match-all forwarding.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
metaflow/plugins/metadata_providers/service.py	Anchors forwarded task-metadata regex patterns while preserving the match-all short circuit.
test/unit/test_service_metadata_provider.py	Verifies exact and descendant patterns are anchored and match-all remains unfiltered.

_{Reviews (2): Last reviewed commit: "Scope fix to service metadata provider" | Re-trigger Greptile}

[nileshpatil6]

Thanks for the credit and for laying out the overlap so clearly, that was a considerate way to handle it.

The split you proposed works well from my side: #3342 has been open since Aug 16 with the local provider fix (regex.match to regex.fullmatch) and a prefix-matching test that fails on master, and the service-side anchoring here is genuinely the piece it does not cover. So landing #3342 for the local half and scoping this one to the service provider seems like the cleanest path.

@talsperre happy to go with whatever ordering you prefer.

[winklemad]

Thanks @nileshpatil6, likewise, your #3342 nailed the local-provider side. Hoping we can get both landed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (master@ddef84a). Learn more about missing BASE report.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #3357   +/-   ##
=========================================
  Coverage          ?   31.02%           
=========================================
  Files             ?      382           
  Lines             ?    52717           
  Branches          ?     9303           
=========================================
  Hits              ?    16353           
  Misses            ?    35153           
  Partials          ?     1211           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[winklemad]

Thanks for the review @talsperre 🙏