fix(exe)[cmp]: don't lint generated commit headers

Merge commits, reverts, autosquash markers, and release bumps used to
fail the keyword parser and block the commit. Skip them before parsing,
controlled by a new `default-ignores` key in [commit] (on unless
disabled), mirroring commitlint's defaultIgnores option.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: ryansuhartanto

crates/atypical-commit/src/config.rs

@@ -16,6 +16,9 @@ pub struct CommitConfig {
     pub enclosures: Vec<EnclosureConfig>,
     pub separator: char,
     pub modifier_sequence: Sequence,
+    /// Skip machine-generated headers (merges, reverts, version
+    /// bumps...); not part of the grammar, so absent from `Tokens`.
+    pub default_ignores: bool,
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -57,6 +60,7 @@ impl From<&Tokens<'_>> for CommitConfig {
                 .collect(),
             separator: tokens.separator,
             modifier_sequence: tokens.modifier_sequence,
+            default_ignores: true,
         }
     }
 }
@@ -129,6 +133,16 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_default_ignores_is_on_unless_disabled() {
+        assert!(CommitConfig::default().default_ignores);
+
+        let config: CommitConfig =
+            toml::from_str("default-ignores = false").unwrap();
+
+        assert!(!config.default_ignores);
+    }
+
     #[test]
     fn test_modifier_sequence_names() {
         let config: CommitConfig =

crates/atypical-commit/src/main.rs

@@ -117,6 +117,11 @@ fn main() -> Result<Exit> {
 
     use chumsky::Parser;
     let config = commit_config(args.config)?;
+
+    if config.default_ignores && atypical_commit::ignore::is_ignored(header) {
+        return Ok(Exit::Success);
+    }
+
     let tokens = atypical_commit::Tokens::from(&config);
     let result = header_parser(&tokens).parse(header);
 

crates/atypical-commit/tests/cli.rs

@@ -75,6 +75,34 @@ fn valid_header_after_blank_lines_and_crlf() {
     assert_eq!(output.status.code(), Some(0));
 }
 
+#[test]
+fn generated_messages_are_ignored() {
+    for header in [
+        "Merge pull request #1 from repo/branch\n",
+        "Merge branch 'main' into fix/default-ignore\n",
+        "Revert \"add(lib)[int]: something\"\n",
+        "fixup! add(lib)[int]: something\n",
+        "chore(release): v1.2.3 [skip ci]\n",
+    ] {
+        let output = lint(&["-"], Some(header));
+
+        assert_eq!(output.status.code(), Some(0), "not ignored: {header}");
+    }
+}
+
+#[test]
+fn default_ignores_can_be_disabled() {
+    let config =
+        fixture("no-ignores.toml", "[commit]\ndefault-ignores = false\n");
+    let config = config.to_str().unwrap();
+    let header = Some("Merge branch 'main'\n");
+
+    let output = lint(&["--config", config, "-"], header);
+
+    assert_eq!(output.status.code(), Some(1));
+    assert!(stderr(&output).contains("unknown keyword `Merge`"));
+}
+
 #[test]
 fn invalid_keyword_reports_and_fails() {
     let output = lint(&["-"], Some("feat: wrong style\n"));