fix(models): keep merged baseline empty after a conflict

Extra High on #1053: three raw ids sharing a provider + display
name cleared then refilled savingsBaselineModel because empty
meant both "none seen" and "conflict". Track distinct baselines
in a Set and emit one only when a single non-empty value remains.

src/models-report.ts

@@ -167,6 +167,10 @@ export async function aggregateModels(projects: ProjectSummary[], opts: Aggregat
   const foldedCategoryCost = new Map<string, Map<CategoryKey, number>>()
   const foldedTotalCost = new Map<string, number>()
   const foldedRawSeen = new Set<string>()
+  // Empty string on the row means both "none seen" and "conflict". Track
+  // distinct non-empty baselines separately so a later bucket cannot
+  // repopulate a conflict that was already detected.
+  const baselinesByKey = new Map<string, Set<string>>()
 
   for (const bucket of buckets.values()) {
     const meta = await resolveProvider(bucket.provider)
@@ -184,6 +188,11 @@ export async function aggregateModels(projects: ProjectSummary[], opts: Aggregat
         })
       : null
 
+    const baselines = baselinesByKey.get(resolvedKey) ?? new Set<string>()
+    if (bucket.savingsBaselineModel) baselines.add(bucket.savingsBaselineModel)
+    baselinesByKey.set(resolvedKey, baselines)
+    const resolvedBaseline = baselines.size === 1 ? [...baselines][0]! : ''
+
     const existing = rowsByKey.get(resolvedKey)
     if (existing) {
       existing.inputTokens += bucket.inputTokens
@@ -195,12 +204,7 @@ export async function aggregateModels(projects: ProjectSummary[], opts: Aggregat
       existing.savingsUSD += bucket.savingsUSD
       existing.calls += bucket.calls
       if (bucket.model < existing.model) existing.model = bucket.model
-      if (existing.savingsBaselineModel && bucket.savingsBaselineModel
-        && existing.savingsBaselineModel !== bucket.savingsBaselineModel) {
-        existing.savingsBaselineModel = ''
-      } else if (!existing.savingsBaselineModel && bucket.savingsBaselineModel) {
-        existing.savingsBaselineModel = bucket.savingsBaselineModel
-      }
+      existing.savingsBaselineModel = resolvedBaseline
       if (existing.credits === null || bucketCredits === null) existing.credits = null
       else existing.credits += bucketCredits
     } else {
@@ -218,7 +222,7 @@ export async function aggregateModels(projects: ProjectSummary[], opts: Aggregat
         totalTokens: total,
         costUSD: bucket.costUSD,
         savingsUSD: bucket.savingsUSD,
-        savingsBaselineModel: bucket.savingsBaselineModel,
+        savingsBaselineModel: resolvedBaseline,
         calls: bucket.calls,
         credits: bucketCredits,
       })

tests/models-report.test.ts

@@ -37,6 +37,8 @@ function makeCall(opts: {
   output?: number
   cacheWrite?: number
   cacheRead?: number
+  savingsUSD?: number
+  savingsBaselineModel?: string
 }): ParsedApiCall {
   return {
     provider: opts.provider,
@@ -58,6 +60,8 @@ function makeCall(opts: {
     timestamp: '2026-05-09T00:00:00.000Z',
     bashCommands: [],
     deduplicationKey: `${opts.provider}-${opts.model}-${opts.costUSD}`,
+    savingsUSD: opts.savingsUSD,
+    savingsBaselineModel: opts.savingsBaselineModel,
   }
 }
 
@@ -228,6 +232,29 @@ describe('aggregateModels', () => {
     expect(rows[0]!.topCategoryShare).toBeCloseTo(0.246 / 0.265, 3)
   })
 
+  it('clears a merged savings baseline when three raw ids disagree', async () => {
+    const rows = await aggregateModels([makeProject([
+      makeTurn('feature', [makeCall({
+        provider: 'cline-cli', model: 'glm-5p2',
+        costUSD: 1, savingsUSD: 2, savingsBaselineModel: 'gpt-4o',
+      })]),
+      makeTurn('feature', [makeCall({
+        provider: 'cline-cli', model: 'GLM-5.2',
+        costUSD: 1, savingsUSD: 2, savingsBaselineModel: 'claude-sonnet-4-6',
+      })]),
+      makeTurn('feature', [makeCall({
+        provider: 'cline-cli', model: 'accounts/fireworks/models/glm-5p2',
+        costUSD: 1, savingsUSD: 2, savingsBaselineModel: 'gpt-5',
+      })]),
+    ])])
+    expect(rows).toHaveLength(1)
+    expect(rows[0]!.provider).toBe('cline-cli')
+    expect(rows[0]!.modelDisplayName).toBe('GLM-5.2')
+    expect(rows[0]!.savingsUSD).toBe(6)
+    expect(rows[0]!.savingsBaselineModel).toBe('')
+    expect(rows[0]!.calls).toBe(3)
+  })
+
   it('does not merge the same display name across providers', async () => {
     const rows = await aggregateModels([makeProject([
       makeTurn('feature', [makeCall({ provider: 'cline-cli', model: 'glm-5p2', costUSD: 1 })]),