From 0fd223d1bd4e9322c11ad57c6bbe4dccd92fbf5a Mon Sep 17 00:00:00 2001
From: rsk-731 <rsk-731@users.noreply.github.com>
Date: Mon, 20 Jul 2026 11:21:14 +0000
Subject: [PATCH] fix(desktop): stop dual main lanes for non-git project
 workspaces

Live overlay always placed sessions under `::branch::main`, while the
backend non-git heuristic keys the lane by folder path (label =
basename). Overlay missed that lane by id/label and forked a phantom
`main` group with the same sessions.

Match existing path-keyed isMain lanes before creating a branch-style
main lane. Covers the codex-research-guardian-style drill-in duplicate.
---
 .../sidebar/projects/workspace-groups.test.ts | 71 +++++++++++++++++++
 .../chat/sidebar/projects/workspace-groups.ts | 15 ++++
 2 files changed, 86 insertions(+)

diff --git a/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.test.ts b/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.test.ts
index b2a893af58..6548d4a3b6 100644
--- a/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.test.ts
+++ b/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.test.ts
@@ -697,6 +697,77 @@ describe('overlayLiveLanes', () => {
     expect(overlaid.repos[0].groups.flatMap(g => g.sessions.map(s => s.id))).toEqual(['dup'])
   })
 
+  it('does not fork a phantom main lane for a non-git backend workspace lane', () => {
+    // Backend non-git heuristic (`project_tree._place_by_heuristic`): lane id =
+    // folder path, label = basename, isMain=true. Live overlay used to always
+    // place under `::branch::main` / label "main", miss that lane by id+label,
+    // and CREATE a second main lane with the same sessions — dual lanes in the
+    // project drill-in (e.g. main + codex-research-guardian).
+    const root = '/home/hermes/hermes-workspace/codex-research-guardian'
+    const a = makeSession(root, { id: 's1' }) // empty git_branch / git_repo_root
+    const b = makeSession(root, { id: 's2' })
+
+    const project = projectNode({
+      id: root,
+      isAuto: true,
+      path: root,
+      repos: [
+        {
+          id: root,
+          label: 'codex-research-guardian',
+          path: root,
+          sessionCount: 2,
+          groups: [
+            lane({
+              id: root,
+              label: 'codex-research-guardian',
+              isMain: true,
+              path: root,
+              sessions: [a, b]
+            })
+          ]
+        }
+      ]
+    })
+
+    const overlaid = overlayLiveLanes(project, [a, b])
+    const groups = overlaid.repos[0].groups
+
+    expect(groups).toHaveLength(1)
+    expect(groups[0].id).toBe(root)
+    expect(groups[0].label).toBe('codex-research-guardian')
+    expect(groups[0].sessions.map(s => s.id).sort()).toEqual(['s1', 's2'])
+    expect(groups.some(g => g.label === 'main' || g.id.endsWith('::branch::main'))).toBe(false)
+  })
+
+  it('joins a fresh live session into an existing non-git workspace lane (no branch id)', () => {
+    const root = '/work/notes'
+    const existing = makeSession(root, { id: 'old' })
+
+    const project = projectNode({
+      id: root,
+      isAuto: true,
+      path: root,
+      repos: [
+        {
+          id: root,
+          label: 'notes',
+          path: root,
+          sessionCount: 1,
+          groups: [lane({ id: root, label: 'notes', isMain: true, path: root, sessions: [existing] })]
+        }
+      ]
+    })
+
+    const fresh = makeSession(root, { id: 'fresh' })
+    const overlaid = overlayLiveLanes(project, [existing, fresh])
+    const groups = overlaid.repos[0].groups
+
+    expect(groups).toHaveLength(1)
+    expect(groups[0].id).toBe(root)
+    expect(groups[0].sessions.map(s => s.id).sort()).toEqual(['fresh', 'old'])
+  })
+
   it('adds a new session to an existing worktree lane keyed by a divergent id (matches by path)', () => {
     // Backend keyed the worktree lane off a branch-style id (no live git probe),
     // but the lane PATH is the worktree dir. A new session under that worktree
diff --git a/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.ts b/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.ts
index 353e9d4ad7..756600d495 100644
--- a/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.ts
+++ b/apps/desktop/src/app/chat/sidebar/projects/workspace-groups.ts
@@ -563,6 +563,21 @@ export function overlayRepoLanes(
         (placed.isMain
           ? lanes.find(g => g.isMain && g.label.toLowerCase() === placed.label.toLowerCase())
           : undefined) ??
+        // Non-git backend heuristic (`project_tree._place_by_heuristic`): one
+        // isMain lane keyed by the folder path itself (id === path, label =
+        // basename) — not `::branch::<name>`. Live placement always emits
+        // `::branch::main` / label "main", so id+label miss and used to FORK a
+        // phantom second main lane with the same sessions. Prefer the existing
+        // path-keyed main lane when present.
+        (placed.isMain && placedKey
+          ? lanes.find(
+              g =>
+                g.isMain &&
+                pathKey(g.path) === placedKey &&
+                !g.id.includes('::branch::') &&
+                !g.id.includes('::kanban')
+            )
+          : undefined) ??
         (!placed.isMain && placedKey ? lanes.find(g => pathKey(g.path) === placedKey) : undefined)
 
       if (!lane) {