feat(scripts): add --dry-run flag to create-new-feature by rhuss · Pull Request #1998 · github/spec-kit

rhuss · 2026-03-27T17:16:17Z

Summary

Add --dry-run / -DryRun flag to both bash and PowerShell create-new-feature scripts
Computes next branch name, spec file path, and feature number without creating branches, directories, or files
Queries remote branches via git ls-remote --heads (read-only) for accurate numbering without mutating local state. This contrasts with the normal (non-dry-run) path which runs git fetch --all --prune to update local remote-tracking refs.
JSON output includes DRY_RUN field when flag is active; omitted otherwise (backwards compatible)
Enables external tools (e.g., worktree-based workflows) to query the next available name before running the full specify workflow

Closes #1931. Also addresses aspects of #1680, #841, and #1921.

Changes

File	Change
`scripts/bash/create-new-feature.sh`	Add `--dry-run` flag, gate branch/dir creation, add `DRY_RUN` to JSON, add `_extract_highest_number` shared helper, add `get_highest_from_remote_refs` using `git ls-remote`, add `skip_fetch` param to `check_existing_branches`
`scripts/powershell/create-new-feature.ps1`	Add `-DryRun` switch, mirror bash logic, add `Get-HighestNumberFromNames` shared helper, add `Get-HighestNumberFromRemoteRefs`, add `-SkipFetch` param to `Get-NextBranchNumber`
`tests/test_timestamp_branches.py`	Add `TestDryRun` class (12 tests including remote branch awareness), add `TestPowerShellDryRun` class (5 tests, skipped without pwsh)

Remote branch handling

Mode	How remotes are queried	Side effects
Normal (no `--dry-run`)	`git fetch --all --prune` then `git branch -a`	Updates local remote-tracking refs
`--dry-run`	`git ls-remote --heads` per remote, plus `git branch -a`	None (read-only query, no local ref updates)

Both modes produce the same numbering result given the same remote state. The difference is that dry-run never modifies .git/refs/remotes/.

Test plan

All 18 existing tests pass unchanged (backwards compatibility)
12 new bash dry-run tests cover: sequential numbering, no branch created, no spec dir created, empty repo, short name, dry-run-then-real-run name match, remote branch awareness, JSON field presence/absence, timestamp mode, number flag, non-git repo
5 PowerShell dry-run tests (skipped without pwsh): name output, no branch, no spec dir, JSON field presence/absence
Manual smoke test: --dry-run --json outputs correct name with zero side effects

Backwards compatibility

Without --dry-run, behavior is 100% unchanged
JSON output shape unchanged when --dry-run is not used (no new fields)
No new dependencies
Refactored shared number extraction helpers reduce code duplication without changing behavior

🤖 Generated with Claude Code

Copilot

Pull request overview

Adds a --dry-run / -DryRun mode to the create-new-feature scripts so external tooling can compute the next branch/spec identifiers (and optionally JSON output) without performing the normal creation workflow.

Changes:

Bash: add --dry-run, skip branch/feature dir/spec file creation when active, and add optional DRY_RUN to JSON output.
PowerShell: add -DryRun with equivalent behavior and JSON shaping.
Tests: add a TestDryRun suite covering dry-run naming and side-effect expectations (bash).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
scripts/bash/create-new-feature.sh	Adds `--dry-run`, gates creation steps, and conditionally emits `DRY_RUN` in JSON output.
scripts/powershell/create-new-feature.ps1	Adds `-DryRun`, mirrors bash dry-run logic, and conditionally emits `DRY_RUN` in JSON output.
tests/test_timestamp_branches.py	Adds dry-run test coverage for naming, JSON field presence/absence, and lack of branch/feature-dir side effects.

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scripts/bash/create-new-feature.sh

scripts/powershell/create-new-feature.ps1

tests/test_timestamp_branches.py

mnriem

Please address Copilot feedback. If not applicable, please explain why

Dry-run was unconditionally creating the root specs/ directory via mkdir -p / New-Item before the dry-run guard. This violated the documented contract of zero side effects. Also adds returncode assertion on git branch --list in tests and adds PowerShell dry-run test coverage (skipped when pwsh unavailable). Addresses review comments on github#1998. Assisted-By: 🤖 Claude Code

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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tests/test_timestamp_branches.py

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

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scripts/powershell/create-new-feature.ps1

Copilot

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Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

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tests/test_timestamp_branches.py

scripts/bash/create-new-feature.sh

scripts/powershell/create-new-feature.ps1

Add a --dry-run / -DryRun flag to both bash and PowerShell create-new-feature scripts that computes the next branch name, spec file path, and feature number without creating any branches, directories, or files. This enables external tools to query the next available name before running the full specify workflow. When combined with --json, the output includes a DRY_RUN field. Without --dry-run, behavior is completely unchanged. Closes github#1931 Assisted-By: 🤖 Claude Code

Dry-run was unconditionally creating the root specs/ directory via mkdir -p / New-Item before the dry-run guard. This violated the documented contract of zero side effects. Also adds returncode assertion on git branch --list in tests and adds PowerShell dry-run test coverage (skipped when pwsh unavailable). Addresses review comments on github#1998. Assisted-By: 🤖 Claude Code

- Gate `mkdir -p $SPECS_DIR` behind DRY_RUN check (bash + PowerShell) so dry-run creates zero directories - Add returncode assertion on `git branch --list` in test - Strengthen spec dir test to verify root `specs/` is not created - Add PowerShell dry-run test class (5 tests, skipped without pwsh) - Fix run_ps_script to use temp repo copy instead of project root Assisted-By: 🤖 Claude Code

Dry-run now queries remote branches via `git ls-remote --heads` (read-only, no fetch) to account for remote-only branches when computing the next sequential number. This prevents dry-run from returning a number that already exists on a remote. Added test verifying dry-run sees remote-only higher-numbered branches and adjusts numbering accordingly. Assisted-By: 🤖 Claude Code

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

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scripts/bash/create-new-feature.sh

tests/test_timestamp_branches.py

Extract shared _extract_highest_number helper (bash) and Get-HighestNumberFromNames (PowerShell) to eliminate duplicated number extraction patterns between local branch and remote ref scanning. Add SkipFetch/skip_fetch parameter to check_existing_branches / Get-NextBranchNumber so dry-run reuses the same function instead of inlining duplicate max-of-branches-and-specs logic. Assisted-By: 🤖 Claude Code

Move remote.git and second_clone directories under git_repo instead of git_repo.parent to prevent path collisions with parallel test workers. Assisted-By: 🤖 Claude Code

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

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tests/test_timestamp_branches.py

scripts/bash/create-new-feature.sh

scripts/powershell/create-new-feature.ps1

- Set GIT_TERMINAL_PROMPT=0 for git ls-remote calls to prevent credential prompts from blocking dry-run in automation scenarios - Add returncode assertion to test_dry_run_with_timestamp git branch --list check Assisted-By: 🤖 Claude Code

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Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

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Copilot AI review requested due to automatic review settings March 27, 2026 17:16

rhuss requested a review from mnriem as a code owner March 27, 2026 17:16

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mnriem requested a review from Copilot March 27, 2026 17:32

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rhuss mentioned this pull request Mar 27, 2026

feat(scripts): add --allow-existing-branch flag to create-new-feature #1999

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rhuss added 3 commits March 28, 2026 06:30

rhuss force-pushed the 001-dry-run-flag branch from c1c467c to ca4f930 Compare March 28, 2026 05:43

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rhuss added 2 commits March 28, 2026 07:09

fix(tests): use isolated paths for remote branch test

594f632

Move remote.git and second_clone directories under git_repo instead of git_repo.parent to prevent path collisions with parallel test workers. Assisted-By: 🤖 Claude Code

Copilot AI review requested due to automatic review settings March 28, 2026 06:11

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fix: address PR review feedback

4da0da6

- Set GIT_TERMINAL_PROMPT=0 for git ls-remote calls to prevent credential prompts from blocking dry-run in automation scenarios - Add returncode assertion to test_dry_run_with_timestamp git branch --list check Assisted-By: 🤖 Claude Code

rhuss requested a review from Copilot March 28, 2026 06:21

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rhuss requested a review from mnriem March 28, 2026 07:14

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rhuss commented Mar 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Changes

Remote branch handling

Test plan

Backwards compatibility

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rhuss commented Mar 27, 2026 •

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