[Cases][Templates] Extend cases search by template field label

[MykhailoKondrat]

What & Why

Extends the Cases search bar to also match against template extended field labels. Previously, free-text input only searched title, description, and incremental ID. Now the server tokenizes the search string and checks each token (substring match) against known template field labels — returning cases that have any extended field whose label contains the search term. Quoted phrases like "Start date" are treated as a single multi-word token. Results are OR'd with the existing free-text search, so no existing behavior changes. The search bar placeholder was updated to communicate all three capabilities: free text, field label, and field:value filtering.

How to Test

• Create a template with extended fields (e.g., "Priority", "Start date operation", "End date").
• Create cases using that template and fill in the extended fields.
• Type priority in the All Cases search bar — cases with a "Priority" field should appear alongside title/description matches.
• Type start — cases with fields containing "start" in the label (e.g., "Start date operation") should appear, but not "End date".
• Type "start date" (with quotes) — only fields whose label contains the phrase "start date" should match.
• Combine: priority:high network should filter by Priority=high AND return cases matching "network" in title/description or as a field label.

Checklist

Check the PR satisfies following conditions.

Reviewers should verify this PR satisfies this list as well.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios

[infra-vault-gh-plugin-prod]

Pinging @elastic/kibana-cases (Team:Cases)

[MykhailoKondrat]

@elasticmachine merge upstream

[macroscopeapp]

🟠 High cases/extended_field_search_utils.ts:344

When the same storageKey appears under multiple labels (e.g., "Priority" and "Priority Level" both mapping to priority_as_keyword), the deduplication at line 373 discards all but the first match using seen.has(meta.storageKey). This loses templateVersions from the discarded matches, so buildFieldLabelExistsClauses generates queries that omit those template versions—cases created with those templates won't be found. Consider merging templateVersions arrays when deduplicating instead of skipping entirely.

🤖 Copy this AI Prompt to have your agent fix this:

In file x-pack/platform/plugins/shared/cases/server/services/cases/extended_field_search_utils.ts around line 344:

When the same `storageKey` appears under multiple labels (e.g., "Priority" and "Priority Level" both mapping to `priority_as_keyword`), the deduplication at line 373 discards all but the first match using `seen.has(meta.storageKey)`. This loses `templateVersions` from the discarded matches, so `buildFieldLabelExistsClauses` generates queries that omit those template versions—cases created with those templates won't be found. Consider merging `templateVersions` arrays when deduplicating instead of skipping entirely.

Evidence trail:
x-pack/platform/plugins/shared/cases/server/services/cases/extended_field_search_utils.ts lines 302-338 (buildLabelToMetasIndex - separate entries per label, each with own templateVersions), lines 344-385 (resolveFieldLabelSearch - dedup with seen.has drops subsequent entries), lines 412-440 (buildFieldLabelExistsClauses - uses templateVersions to build query filters). All at REVIEWED_COMMIT.

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 1fe492b

Failed CI Steps

• FTR Configs #184
• FTR Configs #184

Test Failures

• [job] [logs] FTR Configs #184 / Entity Analytics - Entity Resolution @ess @serverless @skipInServerlessMKI Entity Resolution CSV Upload "before all" hook for "should link matching entities to a target"
• [job] [logs] FTR Configs #184 / Entity Analytics - Entity Resolution @ess @serverless @skipInServerlessMKI Entity Resolution CSV Upload "before all" hook for "should link matching entities to a target"

Metrics [docs]

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
cases	172.0KB	172.1KB	+31.0B

History

• 💛 Build #437159 was flaky 22bff01
• 💛 Build #435748 was flaky b8a8624