custom_major/minor_increment_regex ignored for multiline commits when conventional_commits = false

### Is there an existing issue for this? - [x] I have searched the existing issues ### Description of the bug Summary When conventional_commits = false and a multiline commit is passed via --with-commit, git-cliff silently falls back to a patch bump even when the commit subject matches custom_major_increment_regex or custom_minor_increment_regex. The bump rules are completely ignored. --- Configuration (cliff.toml) [git] conventional_commits = false commit_parsers = [ { message = "^breaking", group = "🚀 🚀 Breaking Changes" }, { message = "^feat", group = "✨ Features" }, { message = "^fix", group = "🐛 Bug Fixes" }, { message = "^other", group = "📦 other", skip = true } ] [bump] custom_major_increment_regex = "^breaking" [changelog] trim = false body = """ ... """ I have intentionally disabled conventional_commits because my commit messages do not follow the type(scope): description structure. They are free-form strings that start with a known prefix (breaking, feat, fix). The custom_*_increment_regex fields exist precisely to support this use case. --- Reproduction # Single-line commit — works correctly, bumps MAJOR git cliff --config cliff.toml \ --tag-pattern '^nati-[0-9]+\.[0-9]+\.[0-9]+$' \ --bump --bumped-version \ --with-commit 'breaking: remove v1 endpoints' \ -- HEAD..HEAD # → nati-2.0.0 ✓ # Multiline commit (subject + body, no blank-line separator) — WRONG, bumps PATCH git cliff --config cliff.toml \ --tag-pattern '^nati-[0-9]+\.[0-9]+\.[0-9]+$' \ --bump --bumped-version \ --with-commit $'breaking: remove v1 endpoints\nThis removes the entire /v1 API surface.' \ -- HEAD..HEAD # → nati-1.0.1 ✗ (expected nati-2.0.0) The only difference between the two calls is a \n followed by body text. The subject line is identical. --- Expected behaviour When conventional_commits = false, git-cliff should evaluate custom_major_increment_regex and custom_minor_increment_regex against the commit subject only (the first line), ignoring everything after the first newline. This is consistent with how conventional commit parsing works — the subject is always the first line. A commit starting with breaking should bump major. A commit starting with feat should bump minor. This should hold whether the commit is single-line or multiline. --- Actual behaviour When a multiline string is passed, git-cliff appears to fail to isolate the subject and applies no bump rule — falling back to patch regardless of the prefix. --- Workaround Passing only the first line to --with-commit for bump calculation, then passing the full multiline string for changelog generation: # bump call: subject only bump_commit_args = " ".join( f"--with-commit {shlex.quote(c.splitlines()[0])}" for c in commits ) # changelog call: full multiline with_commit_args = " ".join( f"--with-commit {shlex.quote(c)}" for c in commits ) This is a functional workaround but requires splitting one logical operation into two separate git-cliff invocations. --- git-cliff version: 2.10.1 OS: Linux ### Steps To Reproduce 1. Create a test git repo mkdir /tmp/cliff-test && cd /tmp/cliff-test git init git commit --allow-empty -m "initial" git tag nati-1.0.0 2. Create cliff.toml [git] conventional_commits = false commit_parsers = [ { message = "^breaking", group = "🚀 Breaking Changes" }, { message = "^feat", group = "✨ Features" }, { message = "^fix", group = "🐛 Bug Fixes" }, ] [bump] custom_major_increment_regex = "^breaking" custom_minor_increment_regex = "^feat" 3. Single-line commit — works correctly git cliff --config cliff.toml \ --tag-pattern '^nati-[0-9]+\.[0-9]+\.[0-9]+$' \ --bump --bumped-version \ --with-commit 'breaking: remove v1 endpoints' \ -- HEAD..HEAD Expected: nati-2.0.0 Actual: nati-2.0.0 ✓ 4. Same subject + body with no blank-line separator — breaks git cliff --config cliff.toml \ --tag-pattern '^nati-[0-9]+\.[0-9]+\.[0-9]+$' \ --bump --bumped-version \ --with-commit $'breaking: remove v1 endpoints\nThis removes the entire /v1 API surface.' \ -- HEAD..HEAD Expected: nati-2.0.0 (subject still starts with breaking) Actual: nati-1.0.1 ✗ — patch bump, bump rules silently ignored 5. Confirm the subject alone still works git cliff --config cliff.toml \ --tag-pattern '^nati-[0-9]+\.[0-9]+\.[0-9]+$' \ --bump --bumped-version \ --with-commit 'breaking: remove v1 endpoints' \ -- HEAD..HEAD Expected: nati-2.0.0 Actual: nati-2.0.0 ✓ — stripping the body to subject-only restores correct behaviour --- The only variable between steps 3 and 4 is the \n followed by body text. The subject breaking: remove v1 endpoints is identical in both. ### Expected behavior When conventional_commits = false, git-cliff should evaluate custom_major_increment_regex and custom_minor_increment_regex against the commit subject only (the first line), ignoring everything after the first newline. This is consistent with how conventional commit parsing works — the subject is always the first line. A commit starting with breaking should bump major. A commit starting with feat should bump minor. This should hold whether the commit is single-line or multiline. ### Screenshots / Logs _No response_ ### Software information git-cliff version: 2.12 OS: Linux ### Additional context _No response_