feat(list): flag a branch checked out in more than one worktree

docs/content/list.md

@@ -172,6 +172,7 @@ An in-progress git operation, a worktree-location attribute, or a branch with no
 | `↻` | `operation_state` `"rebase"`, `"merge"`, `"cherry_pick"`, `"revert"`, `"bisect"` | A git operation is in progress; `git status` names it |
 | `⊟` | `worktree.state` `"prunable"` | Prunable (worktree directory missing) |
 | `⊞` | `worktree.state` `"locked"` | Locked worktree |
+| `⚑` | `worktree.state` `"duplicate_branch"` | Branch checked out in more than one worktree, so `wt` resolves it to whichever git lists first; every worktree on the branch is flagged |
 | `⚑` | `worktree.state` `"branch_worktree_mismatch"` | Branch name doesn't match the worktree path |
 | `/` | `kind` `"branch"` | Branch without a worktree (no `worktree` object) |
 
@@ -243,6 +244,7 @@ One envelope object. Items carry independent facts; rendered strings
                "committed_at": "2025-01-01T08:00:00Z"},
       "worktree": {"path": "/home/user/repo.feature", "main": false, "current": true,
                    "previous": false, "detached": false, "branch_mismatch": false,
+                   "duplicate_branch": false,
                    "changes": {"staged": false, "modified": true, "untracked": false,
                                "renamed": false, "deleted": false, "conflicted": false,
                                "diff": {"added": 10, "deleted": 2}}},
@@ -274,7 +276,7 @@ Item fields:
 | `branch` | Branch name; null for a detached-HEAD worktree. Remote rows carry the bare name with the remote in `remote` |
 | `remote` | Remote name, present only on remote-only branch rows |
 | `head` | `{sha, short_sha, subject, committed_at}`; null for unborn branches. `committed_at` is RFC 3339 UTC |
-| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
+| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, duplicate_branch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
 | `default_branch` | Relation to the default branch: `{ahead, behind, diff, orphan, integration, merge_conflicts}`; absent on the default branch itself. `integration.reason` is one of `same_commit`, `ancestor`, `no_added_changes`, `trees_match`, `merge_adds_nothing`, `patch_id_match`; a dirty tree skips the checks, leaving `integration` null |
 | `upstream` | Tracking branch: `{remote, branch, ahead, behind}`; absent when none is configured |
 | `pr` | Open PR/MR: `{number, url, review, mergeable, repo}`; collected with `--full` or a listed `ci` column. `review` uses the schema 1 `ci.review_state` vocabulary; `mergeable` is false when the forge reports conflicts, null otherwise |
@@ -374,7 +376,7 @@ Present only for worktree-kind items. `state` is the worktree-location attribute
 
 | Field | Type | Description |
 |-------|------|-------------|
-| `state` | string | `"branch_worktree_mismatch"`, `"prunable"`, or `"locked"` (absent when normal) |
+| `state` | string | `"branch_worktree_mismatch"`, `"duplicate_branch"`, `"prunable"`, or `"locked"` (absent when normal) |
 | `reason` | string | Reason for locked/prunable state |
 | `detached` | boolean | HEAD is detached |
 

plugins/worktrunk/skills/worktrunk/reference/list.md

@@ -157,6 +157,7 @@ An in-progress git operation, a worktree-location attribute, or a branch with no
 | `↻` | `operation_state` `"rebase"`, `"merge"`, `"cherry_pick"`, `"revert"`, `"bisect"` | A git operation is in progress; `git status` names it |
 | `⊟` | `worktree.state` `"prunable"` | Prunable (worktree directory missing) |
 | `⊞` | `worktree.state` `"locked"` | Locked worktree |
+| `⚑` | `worktree.state` `"duplicate_branch"` | Branch checked out in more than one worktree, so `wt` resolves it to whichever git lists first; every worktree on the branch is flagged |
 | `⚑` | `worktree.state` `"branch_worktree_mismatch"` | Branch name doesn't match the worktree path |
 | `/` | `kind` `"branch"` | Branch without a worktree (no `worktree` object) |
 
@@ -228,6 +229,7 @@ One envelope object. Items carry independent facts; rendered strings
                "committed_at": "2025-01-01T08:00:00Z"},
       "worktree": {"path": "/home/user/repo.feature", "main": false, "current": true,
                    "previous": false, "detached": false, "branch_mismatch": false,
+                   "duplicate_branch": false,
                    "changes": {"staged": false, "modified": true, "untracked": false,
                                "renamed": false, "deleted": false, "conflicted": false,
                                "diff": {"added": 10, "deleted": 2}}},
@@ -259,7 +261,7 @@ Item fields:
 | `branch` | Branch name; null for a detached-HEAD worktree. Remote rows carry the bare name with the remote in `remote` |
 | `remote` | Remote name, present only on remote-only branch rows |
 | `head` | `{sha, short_sha, subject, committed_at}`; null for unborn branches. `committed_at` is RFC 3339 UTC |
-| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
+| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, duplicate_branch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
 | `default_branch` | Relation to the default branch: `{ahead, behind, diff, orphan, integration, merge_conflicts}`; absent on the default branch itself. `integration.reason` is one of `same_commit`, `ancestor`, `no_added_changes`, `trees_match`, `merge_adds_nothing`, `patch_id_match`; a dirty tree skips the checks, leaving `integration` null |
 | `upstream` | Tracking branch: `{remote, branch, ahead, behind}`; absent when none is configured |
 | `pr` | Open PR/MR: `{number, url, review, mergeable, repo}`; collected with `--full` or a listed `ci` column. `review` uses the schema 1 `ci.review_state` vocabulary; `mergeable` is false when the forge reports conflicts, null otherwise |
@@ -395,7 +397,7 @@ Present only for worktree-kind items. `state` is the worktree-location attribute
 
 | Field | Type | Description |
 |-------|------|-------------|
-| `state` | string | `"branch_worktree_mismatch"`, `"prunable"`, or `"locked"` (absent when normal) |
+| `state` | string | `"branch_worktree_mismatch"`, `"duplicate_branch"`, `"prunable"`, or `"locked"` (absent when normal) |
 | `reason` | string | Reason for locked/prunable state |
 | `detached` | boolean | HEAD is detached |
 

src/cli/mod.rs

@@ -913,6 +913,7 @@ An in-progress git operation, a worktree-location attribute, or a branch with no
 | `↻` | `operation_state` `"rebase"`, `"merge"`, `"cherry_pick"`, `"revert"`, `"bisect"` | A git operation is in progress; `git status` names it |
 | `⊟` | `worktree.state` `"prunable"` | Prunable (worktree directory missing) |
 | `⊞` | `worktree.state` `"locked"` | Locked worktree |
+| `⚑` | `worktree.state` `"duplicate_branch"` | Branch checked out in more than one worktree, so `wt` resolves it to whichever git lists first; every worktree on the branch is flagged |
 | `⚑` | `worktree.state` `"branch_worktree_mismatch"` | Branch name doesn't match the worktree path |
 | `/` | `kind` `"branch"` | Branch without a worktree (no `worktree` object) |
 
@@ -984,6 +985,7 @@ One envelope object. Items carry independent facts; rendered strings
                "committed_at": "2025-01-01T08:00:00Z"},
       "worktree": {"path": "/home/user/repo.feature", "main": false, "current": true,
                    "previous": false, "detached": false, "branch_mismatch": false,
+                   "duplicate_branch": false,
                    "changes": {"staged": false, "modified": true, "untracked": false,
                                "renamed": false, "deleted": false, "conflicted": false,
                                "diff": {"added": 10, "deleted": 2}}},
@@ -1015,7 +1017,7 @@ Item fields:
 | `branch` | Branch name; null for a detached-HEAD worktree. Remote rows carry the bare name with the remote in `remote` |
 | `remote` | Remote name, present only on remote-only branch rows |
 | `head` | `{sha, short_sha, subject, committed_at}`; null for unborn branches. `committed_at` is RFC 3339 UTC |
-| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
+| `worktree` | `{path, main, current, previous, detached, locked, prunable, branch_mismatch, duplicate_branch, operation, changes}`; absent on branch-only rows. `locked`/`prunable` are `{reason}` objects and can co-occur; `operation` is `"rebase"` or `"merge"`; `changes` holds the five working-tree flags plus `conflicted` and `diff {added, deleted}` |
 | `default_branch` | Relation to the default branch: `{ahead, behind, diff, orphan, integration, merge_conflicts}`; absent on the default branch itself. `integration.reason` is one of `same_commit`, `ancestor`, `no_added_changes`, `trees_match`, `merge_adds_nothing`, `patch_id_match`; a dirty tree skips the checks, leaving `integration` null |
 | `upstream` | Tracking branch: `{remote, branch, ahead, behind}`; absent when none is configured |
 | `pr` | Open PR/MR: `{number, url, review, mergeable, repo}`; collected with `--full` or a listed `ci` column. `review` uses the schema 1 `ci.review_state` vocabulary; `mergeable` is false when the forge reports conflicts, null otherwise |
@@ -1151,7 +1153,7 @@ Present only for worktree-kind items. `state` is the worktree-location attribute
 
 | Field | Type | Description |
 |-------|------|-------------|
-| `state` | string | `"branch_worktree_mismatch"`, `"prunable"`, or `"locked"` (absent when normal) |
+| `state` | string | `"branch_worktree_mismatch"`, `"duplicate_branch"`, `"prunable"`, or `"locked"` (absent when normal) |
 | `reason` | string | Reason for locked/prunable state |
 | `detached` | boolean | HEAD is detached |
 

src/commands/list/collect/mod.rs

@@ -1132,6 +1132,11 @@ pub fn collect(
     // (paths from git worktree list may differ based on symlinks or working directory)
     let main_worktree_canonical = canonicalize(&main_worktree.path).ok();
 
+    // Branches living in more than one worktree. Every row on such a branch
+    // is flagged, including the one `wt` resolves to: that choice is git's
+    // listing order, so no row is the legitimate one.
+    let duplicated = worktrunk::git::duplicated_branches(worktrees);
+
     // URL template already fetched in parallel join (layout needs to know if column is needed)
     // Initialize worktree items with identity fields and None for computed fields
     let mut all_items: Vec<ListItem> = sorted_worktrees
@@ -1158,6 +1163,10 @@ pub fn collect(
             let mut worktree_data =
                 WorktreeData::from_worktree(wt, is_main, is_current, is_previous);
             worktree_data.branch_worktree_mismatch = branch_worktree_mismatch;
+            worktree_data.duplicate_branch = wt
+                .branch
+                .as_deref()
+                .is_some_and(|branch| duplicated.contains(branch));
 
             // URL expanded post-skeleton to minimize time-to-skeleton
             ListItem {

src/commands/list/json_output.rs

@@ -214,7 +214,8 @@ pub struct JsonRemote {
 /// Worktree-specific state
 #[derive(Debug, Clone, Serialize, JsonSchema)]
 pub struct JsonWorktree {
-    /// Worktree state: "branch_worktree_mismatch", "prunable", "locked" (absent when normal)
+    /// Worktree state: "branch_worktree_mismatch", "duplicate_branch",
+    /// "prunable", "locked" (absent when normal)
     #[serde(skip_serializing_if = "Option::is_none")]
     pub state: Option<&'static str>,
 
@@ -455,6 +456,7 @@ fn worktree_state_to_json(
         Some(WorktreeState::BranchWorktreeMismatch) => {
             return (Some("branch_worktree_mismatch"), None);
         }
+        Some(WorktreeState::DuplicateBranch) => return (Some("duplicate_branch"), None),
         Some(WorktreeState::Prunable) => return (Some("prunable"), data.prunable.clone()),
         Some(WorktreeState::Locked) => return (Some("locked"), data.locked.clone()),
     }
@@ -825,6 +827,7 @@ mod tests {
             has_working_tree_conflicts: None,
             git_operation: Some(None),
             branch_worktree_mismatch: false,
+            duplicate_branch: false,
         }
     }
 

src/commands/list/json_v2.rs

@@ -179,8 +179,8 @@ pub struct JsonHead {
 }
 
 /// Worktree facts. Location attributes (`locked`, `prunable`,
-/// `branch_mismatch`) are independent fields — unlike schema 1's single
-/// `state`, they can co-occur.
+/// `branch_mismatch`, `duplicate_branch`) are independent fields — unlike
+/// schema 1's single `state`, they can co-occur.
 #[derive(Debug, Serialize, JsonSchema)]
 pub struct JsonWorktreeV2 {
     /// Filesystem path.
@@ -210,6 +210,9 @@ pub struct JsonWorktreeV2 {
     /// created for.
     pub branch_mismatch: bool,
 
+    /// Another worktree has the same branch checked out.
+    pub duplicate_branch: bool,
+
     /// In-progress operation: `"rebase"`, `"merge"`, `"cherry_pick"`,
     /// `"revert"`, or `"bisect"`; absent when none, null while unresolved.
     #[serde(skip_serializing_if = "Tri::is_absent")]
@@ -596,6 +599,7 @@ fn json_worktree(data: &WorktreeData) -> JsonWorktreeV2 {
         locked: reason(&data.locked),
         prunable: reason(&data.prunable),
         branch_mismatch: data.branch_worktree_mismatch,
+        duplicate_branch: data.duplicate_branch,
         operation,
         changes,
     }