fix(codex-usage): count fork-copied Codex token events once (#33478)

Codex usage no longer double-counts forked sessions: forks copy the parent's token_count events with fresh timestamps, so cumulative events are now keyed on turn id + totals (timestamp fallback when no turn id); the turn id is kept in the incremental-scan checkpoint and the usage cache is rebuilt once.

Fixes #19139
Supersedes #19152

Co-authored-by: Jio Kim <26668612+MeroZemory@users.noreply.github.com>

src/main/codex-usage/codex-rollout-file-parse.ts

@@ -76,6 +76,7 @@ function createParseContext(
       sessionCwd: resume.sessionCwd,
       currentCwd: resume.currentCwd,
       currentModel: resume.currentModel,
+      currentTurnId: resume.currentTurnId,
       previousTotals: resume.previousTotals,
       totalOnlyBaselinePending: false
     }

src/main/codex-usage/codex-rollout-resume-state.ts

@@ -29,6 +29,7 @@ export async function buildCodexRolloutResumeState(
         sessionCwd: context.sessionCwd,
         currentCwd: context.currentCwd,
         currentModel: context.currentModel,
+        currentTurnId: context.currentTurnId,
         previousTotals: context.previousTotals
       }
 }

src/main/codex-usage/codex-usage-provider.ts

@@ -2,8 +2,9 @@ import type { UsageProvider } from '../usage/usage-provider-contract'
 import { scanCodexUsageFilesViaWorker } from '../usage/usage-scan-worker-spawn'
 import type { CodexUsageDailyAggregate, CodexUsageSession } from './types'
 
-// Rescan older caches: v5 deduplicates forks across sessions; v6 adds per-request long-context counts.
-export const CODEX_USAGE_SCHEMA_VERSION = 6
+// Rescan older caches: v5 deduplicates forks across sessions; v6 adds per-request long-context counts;
+// v7 keys fork copies on turn id because forks rewrite copied timestamps.
+export const CODEX_USAGE_SCHEMA_VERSION = 7
 
 export const codexUsageProvider = {
   id: 'codex',

src/main/codex-usage/codex-usage-record-parser.ts

@@ -19,6 +19,7 @@ export type CodexUsageParseContext = {
   sessionCwd: string | null
   currentCwd: string | null
   currentModel: string | null
+  currentTurnId?: string | null
   previousTotals: CodexUsageRawUsage | null
   totalOnlyBaselinePending?: boolean
 }
@@ -86,6 +87,7 @@ export function parseCodexUsageRecord(
   }
 
   if (parsed.type === 'turn_context') {
+    context.currentTurnId = extractString(parsed.payload.turn_id)
     context.currentCwd =
       extractString(parsed.payload.cwd) ?? context.currentCwd ?? context.sessionCwd
     context.currentModel = extractModel(parsed.payload) ?? context.currentModel
@@ -149,7 +151,12 @@ export function parseCodexUsageRecord(
   return {
     sessionId: context.sessionId,
     timestamp: parsed.timestamp,
-    eventKey: buildCodexUsageEventKey(parsed.timestamp, totalUsage, lastUsage),
+    eventKey: buildCodexUsageEventKey(
+      // Fork copies rewrite timestamps but keep turn ids; last-only deltas need the timestamp to stay distinct.
+      totalUsage && context.currentTurnId ? context.currentTurnId : parsed.timestamp,
+      totalUsage,
+      lastUsage
+    ),
     cwd: context.currentCwd ?? context.sessionCwd,
     model: resolvedModel,
     hasInferredPricing,

src/main/codex-usage/codex-usage-token-delta.ts

@@ -153,7 +153,7 @@ export function resolveCodexUsageDelta(
 }
 
 export function buildCodexUsageEventKey(
-  timestamp: string,
+  recordIdentity: string,
   totalUsage: CodexUsageRawUsage | null,
   lastUsage: CodexUsageRawUsage | null
 ): string {
@@ -168,5 +168,5 @@ export function buildCodexUsageEventKey(
           usage.totalTokens
         ].join(',')
       : ''
-  return [timestamp, tupleOf(totalUsage), tupleOf(lastUsage)].join('|')
+  return [recordIdentity, tupleOf(totalUsage), tupleOf(lastUsage)].join('|')
 }

src/main/codex-usage/scanner-paths.test.ts

@@ -464,6 +464,40 @@ describe('listCodexSessionFiles', () => {
     expect(result.processedFiles[1]?.hasDeferredClaims).toBe(true)
   })
 
+  it('dedupes fork copies whose timestamps Codex rewrote to the fork time', async () => {
+    const sessionsDir = join(userDataDir, 'codex-runtime-home', 'home', 'sessions')
+    mkdirSync(sessionsDir, { recursive: true })
+    const meta = (id: string): string =>
+      `${JSON.stringify({ type: 'session_meta', payload: { id, cwd: join(fakeHomeDir, 'repo') } })}\n`
+    const turn = (turnId: string): string =>
+      `${JSON.stringify({ type: 'turn_context', payload: { turn_id: turnId, cwd: join(fakeHomeDir, 'repo') } })}\n`
+    const parentTurns = (at: string): string =>
+      [turn('turn-1'), usageRecord(at, 10), turn('turn-2'), usageRecord(at, 5, 15)].join('')
+    writeFileSync(
+      join(sessionsDir, 'aaaa-parent.jsonl'),
+      `${meta('parent')}${parentTurns('2026-05-25T12:00:00.000Z')}`
+    )
+    // Each fork copies the parent with rewritten timestamps, then runs an identical new turn.
+    for (const [name, turnId] of [
+      ['bbbb-fork', 'turn-b'],
+      ['cccc-fork', 'turn-c']
+    ]) {
+      writeFileSync(
+        join(sessionsDir, `${name}.jsonl`),
+        `${meta(name)}${meta('parent')}${parentTurns('2026-05-27T12:00:00.000Z')}${turn(turnId)}${usageRecord('2026-05-27T12:01:00.000Z', 7, 22)}`
+      )
+    }
+
+    const result = await scanCodexUsageFiles([], [])
+
+    expect(
+      result.dailyAggregates.reduce((total, aggregate) => total + aggregate.totalTokens, 0)
+    ).toBe(29)
+    expect(
+      result.dailyAggregates.find((aggregate) => aggregate.day === '2026-05-27')?.totalTokens
+    ).toBe(14)
+  })
+
   it('does not re-count the cumulative session for copied total-only records', async () => {
     const sessionsDir = join(userDataDir, 'codex-runtime-home', 'home', 'sessions')
     mkdirSync(sessionsDir, { recursive: true })

src/main/codex-usage/store-persistence.test.ts

@@ -88,7 +88,7 @@ describe('CodexUsageStore', () => {
     } as unknown as CodexUsagePersistedState)
 
     expect(normalized).toEqual({
-      schemaVersion: 6,
+      schemaVersion: CODEX_USAGE_SCHEMA_VERSION,
       worktreeFingerprint: null,
       processedFiles: [],
       sessions: [],

src/main/codex-usage/types.ts

@@ -29,6 +29,7 @@ export type CodexUsageParseResumeState = {
   sessionCwd: string | null
   currentCwd: string | null
   currentModel: string | null
+  currentTurnId?: string | null
   previousTotals: CodexUsageRawUsage | null
 }