Merge a branch only by fast-forward.
Refuse to create an unexpected merge commit.
set -euo pipefail
git switch -qc feature/notes
printf 'second\n' >> notes.txt
git commit -qam 'Add note'
git switch -q main
git merge --ff-only -q feature/notes
git log -1 --format=%sExpected output EXAMPLE
Add note
Details
Requires Git and Bash. Run in a disposable practice repository. The test setup below creates the starting files and commits. --ff-only fails when the histories diverge, leaving you to review the integration.
Tested on Ubuntu 24.04.5 LTS · · git version 2.43.0 · git 1:2.43.0-1ubuntu7.3
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Snippet process uid 65534 with a read-only root filesystem and temporary working files. Networking disabled. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged process) / C.UTF-8
- Interpreter invocation
bash -euo pipefail -c <published code>- Container image ID
sha256:ec91410a8f6ec3e985830b5e3a0560306d36f8c1c5ccd91a6699abe707123fa3- Code SHA-256
b9003a6c2ccd1262339a9145c4bac9c673d66d2e8f1407527dcb2cfdb918e438- Dependencies
- git 1:2.43.0-1ubuntu7.3
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
git init -q -b main . git config user.name 'Example Developer' git config user.email 'developer@example.invalid' git config commit.gpgsign false printf 'first\n' > notes.txt git add notes.txt git commit -qm 'Initial notes'
Observed standard output
Add note
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.