fix(ui): preserve distinct log detail rows

ui/src/components/logs/derive-trace-groups.ts

@@ -17,20 +17,30 @@ export interface LeafItem {
 
 export type DerivedItem = LeafItem | TraceGroup;
 
+function stableStringify(value: unknown): string {
+  if (value === undefined) return '';
+  if (value === null || typeof value !== 'object') return JSON.stringify(value);
+  if (Array.isArray(value)) return `[${value.map((item) => stableStringify(item)).join(',')}]`;
+
+  return `{${Object.entries(value as Record<string, unknown>)
+    .sort(([a], [b]) => a.localeCompare(b))
+    .map(([key, item]) => `${JSON.stringify(key)}:${stableStringify(item)}`)
+    .join(',')}}`;
+}
+
 /**
- * Tuple key for coalescing standalone leaves. Includes `message` and
- * `source` so two adjacent logs that share event/module/level but report
- * different content (or come from a different service) stay distinct
- * (e.g. `User logged in: alice` and `User logged in: bob`). Excludes
- * `latencyMs` and `metadata` because those drift per request even on
- * truly redundant polls — including them would prevent any coalescing.
+ * Tuple key for coalescing standalone leaves. The row/detail UI exposes more
+ * than event/module/level, so every inspectable payload field must participate
+ * in equality; otherwise two adjacent logs with different metadata, context,
+ * error, or latency could collapse into one selectable row. `timestamp` stays
+ * out of the key because collapsed rows surface their time span separately.
  *
  * NB: this only applies to *leaves* (entries without `requestId`). Trace
  * children render uncoalesced so retries and duplicated-stage emissions
  * stay individually inspectable.
  */
 function coalesceKey(entry: LogsEntry): string {
-  return [
+  return JSON.stringify([
     entry.event ?? '',
     entry.message ?? '',
     entry.stage ?? '',
@@ -38,7 +48,13 @@ function coalesceKey(entry: LogsEntry): string {
     entry.level,
     entry.requestId ?? '',
     entry.source ?? '',
-  ].join(' ');
+    entry.runId ?? '',
+    String(entry.processId ?? ''),
+    String(entry.latencyMs ?? ''),
+    stableStringify(entry.context),
+    stableStringify(entry.metadata),
+    stableStringify(entry.error),
+  ]);
 }
 
 /**

ui/tests/unit/ui/components/logs-derive-trace-groups.test.ts

@@ -141,6 +141,65 @@ describe('deriveTraceGroups', () => {
     expect(result.every((r) => r.kind === 'leaf' && r.repeatCount === undefined)).toBe(true);
   });
 
+  it('keeps adjacent leaves with different detail payloads as separate rows', () => {
+    const result = deriveTraceGroups(
+      leafEntries(
+        {
+          id: '1',
+          timestamp: 't1',
+          event: 'poll',
+          message: 'same',
+          latencyMs: 25,
+          metadata: { attempt: 1, nested: { status: 'warm' } },
+          context: { account: 'alpha' },
+          error: { code: 'E_ONE', message: 'first' },
+        },
+        {
+          id: '2',
+          timestamp: 't2',
+          event: 'poll',
+          message: 'same',
+          latencyMs: 50,
+          metadata: { attempt: 2, nested: { status: 'cold' } },
+          context: { account: 'beta' },
+          error: { code: 'E_TWO', message: 'second' },
+        }
+      )
+    );
+
+    expect(result).toHaveLength(2);
+    expect(result.every((r) => r.kind === 'leaf' && r.repeatCount === undefined)).toBe(true);
+    expect(result.map((r) => (r.kind === 'leaf' ? r.entry.id : 'trace'))).toEqual(['2', '1']);
+  });
+
+  it('coalesces leaves with semantically identical structured payloads', () => {
+    const result = deriveTraceGroups(
+      leafEntries(
+        {
+          id: '1',
+          timestamp: 't1',
+          event: 'poll',
+          message: 'tick',
+          latencyMs: 25,
+          metadata: { b: 2, a: 1 },
+          context: { nested: { b: false, a: true } },
+        },
+        {
+          id: '2',
+          timestamp: 't2',
+          event: 'poll',
+          message: 'tick',
+          latencyMs: 25,
+          metadata: { a: 1, b: 2 },
+          context: { nested: { a: true, b: false } },
+        }
+      )
+    );
+
+    expect(result).toHaveLength(1);
+    expect((result[0] as LeafItem).repeatCount).toBe(2);
+  });
+
   it('display-sorts items reverse-chronologically', () => {
     // Use distinct events so leaves don't coalesce — testing display sort,
     // not coalesce.