git worktree add -b ignores branch name when ref matches remote (guess-remote override)

[damianlewis]

Description

When using git gtr new <branch> --from <ref> where <ref> matches a remote tracking branch, git's guess-remote logic overrides the explicit -b flag, creating a tracking branch with the remote branch name instead of the specified branch name.

Steps to Reproduce

1. Have a remote branch origin/feat/my-feature
2. Ensure no local branch feat/my-feature exists
3. Run: git gtr new my-branch --from feat/my-feature --track none

Expected Behavior

• Worktree created with a new branch called my-branch based on feat/my-feature

Actual Behavior

• Worktree folder is named my-branch (correct)
• Branch checked out is feat/my-feature (wrong — should be my-branch)
• No my-branch branch is created
• Git output shows: Preparing worktree (new branch 'feat/my-feature') despite -b my-branch being passed

Trace Evidence

The bash -x trace confirms the correct command is executed by gtr:

++ git worktree add /path/to/worktrees/my-branch -b my-branch feat/my-feature
Preparing worktree (new branch 'feat/my-feature')
branch 'feat/my-feature' set up to track 'origin/feat/my-feature'.
HEAD is now at c630c3f Merge branch 'main' into feat/my-feature

Git ignores -b my-branch and instead creates feat/my-feature as a tracking branch.

Root Cause

The issue is git's DWIM (Do What I Mean) / guess-remote logic. When git worktree add -b <new-branch> <start-point> is called and <start-point> is a string that matches a remote tracking branch name, git overrides the explicit -b flag and creates a tracking branch using the remote branch name instead.

This happens because gtr passes the ref as a branch name string (e.g., feat/my-feature) rather than as an unambiguous commit reference. Git sees the string, matches it to origin/feat/my-feature, and activates its guess-remote behaviour — ignoring the -b flag entirely.

Note: the --no-guess-remote flag could prevent this but requires Git 2.21+. Since gtr targets Git 2.17+ (macOS default), the fix should work across all supported versions.

Environment

• OS: macOS 15.7.4 (Sequoia)
• Git: 2.50.1 (Apple Git-155)
• gtr: 2.4.0
• Shell: zsh / bash

[traycerai]

Plan

Observations

In file:lib/core.sh, _try_worktree_add() (line 352) runs:

git worktree add "$wt_path" "$@" >&2

The >&2 redirect makes git see a non-TTY stdout, which activates git's worktree.guessRemote heuristic. When the from_ref argument (e.g. feat/my-feature) matches a remote tracking branch (origin/feat/my-feature), git silently ignores the explicit -b my-branch flag and creates a tracking branch named feat/my-feature instead.

The two affected call sites in create_worktree() are:

• none track mode (line 475–478): _try_worktree_add … -b "$branch_name" "$from_ref"
• auto fallback (line 492–495): _try_worktree_add … -b "$branch_name" "$from_ref"

Approach

Add --no-guess-remote directly inside _try_worktree_add() before forwarding the remaining args to git worktree add. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when -b is not used and has been available since git 2.18, which is within the supported range (Git 2.17+).

Implementation

1. Update _try_worktree_add in file:lib/core.sh

In the _try_worktree_add function (lines 346–358), change the git worktree add invocation to include --no-guess-remote immediately after add:

git worktree add --no-guess-remote "$wt_path" "$@" >&2

This change ensures that regardless of TTY state, git will never override an explicit -b <branch> flag by guessing a remote tracking branch name. The --no-guess-remote flag prevents git's DWIM (Do What I Mean) logic from activating when a from_ref string matches a remote tracking branch name.

sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch

Loading

No other files need to change. The remote and local track modes and _worktree_add_tracked are unaffected in behaviour since --no-guess-remote is a no-op when the ref is already fully qualified (e.g. origin/branch_name) or when no -b flag is present.

Import In IDE

🤖 Prompt for AI Agents

## Observations

In `file:lib/core.sh`, `_try_worktree_add()` (line 352) runs:
```
git worktree add "$wt_path" "$@" >&2
```
The `>&2` redirect makes git see a non-TTY stdout, which activates git's `worktree.guessRemote` heuristic. When the `from_ref` argument (e.g. `feat/my-feature`) matches a remote tracking branch (`origin/feat/my-feature`), git silently ignores the explicit `-b my-branch` flag and creates a tracking branch named `feat/my-feature` instead.

The two affected call sites in `create_worktree()` are:
- **`none` track mode** (line 475–478): `_try_worktree_add … -b "$branch_name" "$from_ref"`
- **`auto` fallback** (line 492–495): `_try_worktree_add … -b "$branch_name" "$from_ref"`

## Approach

Add `--no-guess-remote` directly inside `_try_worktree_add()` before forwarding the remaining args to `git worktree add`. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when `-b` is not used and has been available since git 2.18, which is within the supported range (Git 2.17+).

## Implementation

### 1. Update `_try_worktree_add` in `file:lib/core.sh`

In the `_try_worktree_add` function (lines 346–358), change the `git worktree add` invocation to include `--no-guess-remote` immediately after `add`:

```
git worktree add --no-guess-remote "$wt_path" "$@" >&2
```

This change ensures that regardless of TTY state, git will never override an explicit `-b <branch>` flag by guessing a remote tracking branch name. The `--no-guess-remote` flag prevents git's DWIM (Do What I Mean) logic from activating when a `from_ref` string matches a remote tracking branch name.

```mermaid
sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch
```

No other files need to change. The `remote` and `local` track modes and `_worktree_add_tracked` are unaffected in behaviour since `--no-guess-remote` is a no-op when the ref is already fully qualified (e.g. `origin/branch_name`) or when no `-b` flag is present.

---

Execution Information

Branch: main
Commit: 0403d74

---

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[traycerai]

I have updated the Implementation Plan to reflect the recent changes in the ticket.

Previous Plan

Observations

In file:lib/core.sh, _try_worktree_add() (line 352) runs:

git worktree add "$wt_path" "$@" >&2

The >&2 redirect makes git see a non-TTY stdout, which activates git's worktree.guessRemote heuristic. When the from_ref argument (e.g. feat/my-feature) matches a remote tracking branch (origin/feat/my-feature), git silently ignores the explicit -b my-branch flag and creates a tracking branch named feat/my-feature instead.

The two affected call sites in create_worktree() are:

• none track mode (line 475–478): _try_worktree_add … -b "$branch_name" "$from_ref"
• auto fallback (line 492–495): _try_worktree_add … -b "$branch_name" "$from_ref"

Approach

Add --no-guess-remote directly inside _try_worktree_add() before forwarding the remaining args to git worktree add. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when -b is not used and has been available since git 2.27.

Implementation

1. Update _try_worktree_add in file:lib/core.sh

In the _try_worktree_add function (lines 346–358), change the git worktree add invocation to include --no-guess-remote immediately after add:

git worktree add --no-guess-remote "$wt_path" "$@" >&2

This single-character change ensures that regardless of TTY state, git will never override an explicit -b <branch> flag by guessing a remote tracking branch name.

sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch

Loading

No other files need to change. The remote and local track modes and _worktree_add_tracked are unaffected in behaviour since --no-guess-remote is a no-op when the ref is already fully qualified (e.g. origin/branch_name) or when no -b flag is present.

Import In IDE

🤖 Prompt for AI Agents

## Observations

In `file:lib/core.sh`, `_try_worktree_add()` (line 352) runs:
```
git worktree add "$wt_path" "$@" >&2
```
The `>&2` redirect makes git see a non-TTY stdout, which activates git's `worktree.guessRemote` heuristic. When the `from_ref` argument (e.g. `feat/my-feature`) matches a remote tracking branch (`origin/feat/my-feature`), git silently ignores the explicit `-b my-branch` flag and creates a tracking branch named `feat/my-feature` instead.

The two affected call sites in `create_worktree()` are:
- **`none` track mode** (line 475–478): `_try_worktree_add … -b "$branch_name" "$from_ref"`
- **`auto` fallback** (line 492–495): `_try_worktree_add … -b "$branch_name" "$from_ref"`

## Approach

Add `--no-guess-remote` directly inside `_try_worktree_add()` before forwarding the remaining args to `git worktree add`. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when `-b` is not used and has been available since git 2.27.

## Implementation

### 1. Update `_try_worktree_add` in `file:lib/core.sh`

In the `_try_worktree_add` function (lines 346–358), change the `git worktree add` invocation to include `--no-guess-remote` immediately after `add`:

```
git worktree add --no-guess-remote "$wt_path" "$@" >&2
```

This single-character change ensures that regardless of TTY state, git will never override an explicit `-b <branch>` flag by guessing a remote tracking branch name.

```mermaid
sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch
```

No other files need to change. The `remote` and `local` track modes and `_worktree_add_tracked` are unaffected in behaviour since `--no-guess-remote` is a no-op when the ref is already fully qualified (e.g. `origin/branch_name`) or when no `-b` flag is present.

---

Execution Information

Branch: main
Commit: 0403d74

New Plan

Observations

In file:lib/core.sh, _try_worktree_add() (line 352) runs:

git worktree add "$wt_path" "$@" >&2

The >&2 redirect makes git see a non-TTY stdout, which activates git's worktree.guessRemote heuristic. When the from_ref argument (e.g. feat/my-feature) matches a remote tracking branch (origin/feat/my-feature), git silently ignores the explicit -b my-branch flag and creates a tracking branch named feat/my-feature instead.

The two affected call sites in create_worktree() are:

• none track mode (line 475–478): _try_worktree_add … -b "$branch_name" "$from_ref"
• auto fallback (line 492–495): _try_worktree_add … -b "$branch_name" "$from_ref"

Approach

Add --no-guess-remote directly inside _try_worktree_add() before forwarding the remaining args to git worktree add. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when -b is not used and has been available since git 2.18, which is within the supported range (Git 2.17+).

Implementation

1. Update _try_worktree_add in file:lib/core.sh

In the _try_worktree_add function (lines 346–358), change the git worktree add invocation to include --no-guess-remote immediately after add:

git worktree add --no-guess-remote "$wt_path" "$@" >&2

This change ensures that regardless of TTY state, git will never override an explicit -b <branch> flag by guessing a remote tracking branch name. The --no-guess-remote flag prevents git's DWIM (Do What I Mean) logic from activating when a from_ref string matches a remote tracking branch name.

sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch

Loading

No other files need to change. The remote and local track modes and _worktree_add_tracked are unaffected in behaviour since --no-guess-remote is a no-op when the ref is already fully qualified (e.g. origin/branch_name) or when no -b flag is present.

Import In IDE

🤖 Prompt for AI Agents

## Observations

In `file:lib/core.sh`, `_try_worktree_add()` (line 352) runs:
```
git worktree add "$wt_path" "$@" >&2
```
The `>&2` redirect makes git see a non-TTY stdout, which activates git's `worktree.guessRemote` heuristic. When the `from_ref` argument (e.g. `feat/my-feature`) matches a remote tracking branch (`origin/feat/my-feature`), git silently ignores the explicit `-b my-branch` flag and creates a tracking branch named `feat/my-feature` instead.

The two affected call sites in `create_worktree()` are:
- **`none` track mode** (line 475–478): `_try_worktree_add … -b "$branch_name" "$from_ref"`
- **`auto` fallback** (line 492–495): `_try_worktree_add … -b "$branch_name" "$from_ref"`

## Approach

Add `--no-guess-remote` directly inside `_try_worktree_add()` before forwarding the remaining args to `git worktree add`. This is a single-point fix that covers all current and future callers uniformly. The flag is harmless when `-b` is not used and has been available since git 2.18, which is within the supported range (Git 2.17+).

## Implementation

### 1. Update `_try_worktree_add` in `file:lib/core.sh`

In the `_try_worktree_add` function (lines 346–358), change the `git worktree add` invocation to include `--no-guess-remote` immediately after `add`:

```
git worktree add --no-guess-remote "$wt_path" "$@" >&2
```

This change ensures that regardless of TTY state, git will never override an explicit `-b <branch>` flag by guessing a remote tracking branch name. The `--no-guess-remote` flag prevents git's DWIM (Do What I Mean) logic from activating when a `from_ref` string matches a remote tracking branch name.

```mermaid
sequenceDiagram
    participant User
    participant gtr as git gtr new
    participant core as _try_worktree_add
    participant git as git worktree add

    User->>gtr: git gtr new my-branch --from feat/my-feature --track none
    gtr->>core: _try_worktree_add <path> … -b my-branch feat/my-feature
    core->>git: git worktree add --no-guess-remote <path> -b my-branch feat/my-feature
    git-->>core: Preparing worktree (new branch 'my-branch') ✓
    core-->>User: Worktree created with new branch my-branch
```

No other files need to change. The `remote` and `local` track modes and `_worktree_add_tracked` are unaffected in behaviour since `--no-guess-remote` is a no-op when the ref is already fully qualified (e.g. `origin/branch_name`) or when no `-b` flag is present.

---

Execution Information

Branch: main
Commit: 0403d74