fix(fn-dashboard): do not mask empty panel query fields

[GurinderRawala]

Problem

A reporting-backed custom dashboard panel failed to render:

error: [Grafana proxy]:: Failed to resolve FN-redacted query {
  dashboardUID: 'cd-7e2676fddaf74e218328',
  queryCount: 1,
  queries: [ { refId: 'A', datasourceUid: 'mfe-bigquery-prod',
               rawSqlPrefix: '[MFE_REDACTED:p:4:A]' } ]
}

Root cause

maskRawQueryFields masked any query field whose value was a string — including the empty string:

if _, err := cur.String(); err == nil {
    obj.Set(field, mask)   // "" -> "[MFE_REDACTED:p:4:A]"
}

Verified against simplejson: CheckGet("rawSql") on "" returns ok=true and String() returns ("", nil), so an empty value took the mask branch.

For a panel that intentionally carries no SQL, that fabricates a marker promising the proxy a query which does not exist. The proxy's contract is to fail closed on any value carrying the redaction prefix — it must parse a valid key rather than forward a literal placeholder upstream. So it resolves panel 4, finds rawSql: "", hits if (!originalSql) return null, and rejects the entire /api/ds/query batch.

Fix

Skip masking when the query field is empty or whitespace-only. Safe by construction: there is no query text to leak, and the marker exists solely to stand in for text that was removed.

Two shapes depend on an intentionally empty query field:

• CodeRabbit reporting-backed panels — data comes from the reporting API via a crReportingTag on the target rather than from SQL.
• Variable metricFindQueries — these already arrive with an empty rawSql and a tempVar<N> refId. The proxy has a dedicated pass-through for exactly this shape (if (raw.length === 0)), which the fabricated marker was routing around. So this also removes a latent inconsistency that predates the reporting work.

Why not gate on "is this a custom dashboard?"

The requested framing was to skip tag generation for custom dashboards specifically, but that isn't the right seam:

1. The fork has no notion of a custom dashboard. pkg/api has no cd- prefix or dashboard-kind concept; introducing one would mean threading a classification through the mask path purely to express "this panel has no SQL" — which the panel already states by having no SQL.
2. Custom dashboards still contain SQL panels. A generated dashboard is typically mixed. Disabling masking per-dashboard would unmask real SQL on the SQL-backed panels — a regression of the property the mask exists to guarantee.
3. An empty query is meaningless to mask on any dashboard. The condition is a property of the value, not of the dashboard.

The narrower predicate fixes the reported failure, keeps every non-empty query masked, and adds no new coupling.

Verification

Check	Result
go build ./pkg/api/	clean
go test ./pkg/api/ -run "TestMask|TestIsCodeRabbitMFE|TestMfe|TestPanelAndVariable"	ok
gofmt -l	clean

Three regression tests added:

• empty rawSql is left untouched, and a sibling crReportingTag survives intact
• whitespace-only query is left untouched
• a mixed dashboard still masks the non-empty query on another panel -> [MFE_REDACTED:p:5:A]

I confirmed the tests actually catch the bug: with the guard removed all three fail with actual: "[MFE_REDACTED:p:4:A]"; with it restored all pass.

Pre-existing failure, unrelated: TestDashboardSnapshotAPIEndpoint_singleSnapshot panics with no guardian factory implementation provided. I confirmed it fails identically on a stashed/clean tree.

Related

Pairs with mono#25309, which generates these reporting-backed panels. Both are needed for a reporting panel to render.

Summary by CodeRabbit

• Bug Fixes
  • Empty or whitespace-only dashboard query fields are now preserved instead of being redacted.
  • Non-empty query fields continue to be masked as expected.
  • Reporting metadata remains unchanged during masking.

[coderabbitai]

📝 Walkthrough

Walkthrough

maskRawQueryFields now leaves empty and whitespace-only string query fields unchanged. It continues to replace non-empty query strings with the supplied redaction marker. Regression tests cover empty rawSql, whitespace-only rawSql, unrelated reporting tags, and mixed empty and non-empty queries.

Poem

I’m a rabbit with queries tucked tight,
Empty fields stay clear and bright.
Whitespace rests without a scar,
Busy queries mask what they are.
Hop, hop—tests guard the bar!

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: preventing masking of empty panel query fields.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch custom-dashboards-reporting-empty-rawsql

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch custom-dashboards-reporting-empty-rawsql

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