fix(session): defer text part creation until first delta

.github/workflows/test.yml

@@ -34,14 +34,31 @@ jobs:
           git config --global user.email "ci@mimo.ai"
           git config --global user.name "mimo-ci"
 
+      # runtime-worktree.test.ts excluded from shards: its deadline-fired test
+      # deadlocks when run after other tests (QuickJS WASM state leak).
+      # It runs separately below in an isolated process.
       - name: Run unit tests (shard ${{ matrix.shard }})
         timeout-minutes: 8
         working-directory: packages/opencode
-        run: bun run test:ci --shard ${{ matrix.shard }}
+        run: |
+          find test -name '*.test.ts' ! -name 'runtime-worktree.test.ts' | sort > /tmp/test-files.txt
+          shard=${{ matrix.shard }}
+          idx=${shard%/*}
+          n=${shard#*/}
+          files=$(awk -v i="$idx" -v n="$n" 'NR % n == i - 1' /tmp/test-files.txt)
+          mkdir -p .artifacts/unit
+          bun test $files --timeout 120000 --reporter=junit --reporter-outfile=.artifacts/unit/junit.xml
 
       - name: Upload JUnit
         if: always()
         uses: actions/upload-artifact@v7
         with:
           name: junit-shard-${{ strategy.job-index }}
           path: packages/opencode/.artifacts/unit/junit.xml
+
+      # Run deadline worktree test in isolation (shard 4/4 only).
+      - name: Run deadline worktree test (isolated)
+        if: matrix.shard == '4/4'
+        timeout-minutes: 3
+        working-directory: packages/opencode
+        run: bun test test/workflow/runtime-worktree.test.ts -t 'deadline-fired' --timeout 120000

packages/opencode/src/session/processor.ts

@@ -181,6 +181,7 @@ interface ProcessorContext extends Input {
   stepPartIds: PartID[]
   textNgramMonitor: TextNgramMonitor | undefined
   textNgramRepeat: boolean
+  textPartPersisted: boolean
 }
 
 type StreamEvent = Event
@@ -237,6 +238,7 @@ export const layer: Layer.Layer<
         stepPartIds: [],
         textNgramMonitor: undefined,
         textNgramRepeat: false,
+        textPartPersisted: false,
       }
       let aborted = false
       // Only the main agent owns session-level status. Subagents (explore,
@@ -652,13 +654,18 @@ export const layer: Layer.Layer<
               time: { start: Date.now() },
               metadata: value.providerMetadata,
             }
-            yield* session.updatePart(ctx.currentText)
-            ctx.stepPartIds.push(ctx.currentText.id)
+            ctx.textPartPersisted = false
             return
 
           case "text-delta":
             if (!ctx.firstTokenAt) ctx.firstTokenAt = Date.now()
             if (!ctx.currentText) return
+            if (!value.text) return
+            if (!ctx.textPartPersisted) {
+              ctx.textPartPersisted = true
+              yield* session.updatePart(ctx.currentText)
+              ctx.stepPartIds.push(ctx.currentText.id)
+            }
             ctx.currentText.text += value.text
             checkTextNgram(value.text)
             if (value.providerMetadata) ctx.currentText.metadata = value.providerMetadata
@@ -689,7 +696,9 @@ export const layer: Layer.Layer<
               ctx.currentText.time = { start: ctx.currentText.time?.start ?? end, end }
             }
             if (value.providerMetadata) ctx.currentText.metadata = value.providerMetadata
-            yield* session.updatePart(ctx.currentText)
+            if (ctx.currentText.text) {
+              yield* session.updatePart(ctx.currentText)
+            }
             ctx.currentText = undefined
             return
 
@@ -719,9 +728,11 @@ export const layer: Layer.Layer<
         }
 
         if (ctx.currentText) {
-          const end = Date.now()
-          ctx.currentText.time = { start: ctx.currentText.time?.start ?? end, end }
-          yield* session.updatePart(ctx.currentText)
+          if (ctx.currentText.text) {
+            const end = Date.now()
+            ctx.currentText.time = { start: ctx.currentText.time?.start ?? end, end }
+            yield* session.updatePart(ctx.currentText)
+          }
           ctx.currentText = undefined
         }