add a only_first_parent option to only consider commits on current branch

src/git/revspec.rs

@@ -70,6 +70,9 @@
     pub fn all_commits(&self) -> Result<CommitRange, Git2Error> {
         let mut revwalk = self.0.revwalk()?;
         revwalk.push_head()?;
+        if SETTINGS.only_first_parent {
+            revwalk.simplify_first_parent()?;
+        }
         let mut commits = vec![];
 
         for oid in revwalk {
@@ -331,6 +334,9 @@
         let mut revwalk = self.0.revwalk()?;
 
         revwalk.push_range(spec)?;
+        if SETTINGS.only_first_parent {
+            revwalk.simplify_first_parent()?;
+        }
 
         let mut commits: Vec<Commit> = vec![];
 

src/settings/mod.rs

@@ -33,6 +33,7 @@ pub struct Settings {
     pub from_latest_tag: bool,
     pub ignore_merge_commits: bool,
     pub generate_mono_repository_global_tag: bool,
+    pub only_first_parent: bool,
     pub monorepo_version_separator: Option<String>,
     pub branch_whitelist: Vec<String>,
     pub tag_prefix: Option<String>,
@@ -55,6 +56,7 @@ impl Default for Settings {
             from_latest_tag: false,
             ignore_merge_commits: false,
             generate_mono_repository_global_tag: true,
+            only_first_parent: false,
             monorepo_version_separator: None,
             branch_whitelist: vec![],
             tag_prefix: None,

tests/lib_tests/log.rs

@@ -4,6 +4,7 @@ use cocogitto::CocoGitto;
 use crate::helpers::*;
 
 use anyhow::Result;
+use cmd_lib::run_cmd;
 use sealed_test::prelude::*;
 use speculoos::prelude::*;
 
@@ -48,3 +49,31 @@ fn get_log_with_no_errors() -> Result<()> {
 
     Ok(())
 }
+
+#[sealed_test]
+fn get_log_on_master_only() -> Result<()> {
+    // Arrange
+    git_init()?;
+    let settings = r#"only_first_parent = true"#;
+    run_cmd!(echo $settings > cog.toml;)?;
+    git_commit("chore: initial commit")?;
+
+    run_cmd!(git checkout -b feature)?;
+    git_commit("feat: a commit on feature branch")?;
+    git_commit("fix: a commit on feature branch")?;
+    run_cmd!(
+        git checkout master;
+        git merge --no-ff -m "feat: feature" feature;
+    )?;
+
+    let filters = CommitFilters(vec![CommitFilter::NoError]);
+    let cocogitto = CocoGitto::get()?;
+
+    // Act
+    let logs = cocogitto.get_log(filters)?;
+
+    // Assert we don't see feature branch commit
+    assert_that!(logs).does_not_contain("a commit on feature branch");
+
+    Ok(())
+}