diff --git a/src/changes.rs b/src/changes.rs
index 95e9076..2c75b80 100644
--- a/src/changes.rs
+++ b/src/changes.rs
@@ -25,13 +25,18 @@ use crate::remote::Remote;
 pub struct RepoChangeset<C: Client> {
     pub name: String,
     pub remote: Remote<C>,
-    pub base_commit: String,
+    pub base_commit: Option<String>,
     pub head_commit: String,
     pub changes: Vec<Changeset>,
 }
 
 impl<C: Client> RepoChangeset<C> {
-    pub fn new(name: String, remote: crate::Remote<C>, base_commit: String, head_commit: String) -> RepoChangeset<C> {
+    pub fn new(
+        name: String,
+        remote: crate::Remote<C>,
+        base_commit: Option<String>,
+        head_commit: String,
+    ) -> RepoChangeset<C> {
         Self {
             name,
             remote,
@@ -45,12 +50,15 @@ impl<C: Client> RepoChangeset<C> {
 impl<C: Client + Sync + Send + 'static> RepoChangeset<C> {
     pub async fn analyze_commits(mut self) -> anyhow::Result<Self> {
         // if this is a newly introduced source, compare the commit to itself
-        if self.head_commit.is_empty() {
-            self.head_commit.clone_from(&self.base_commit);
-            self.base_commit += "^1";
+        if self.base_commit.is_none() {
+            self.base_commit = Some(self.head_commit.clone());
+            self.head_commit += "^1";
         }
 
-        let compare_commits = self.remote.compare(&self.base_commit, &self.head_commit).await?;
+        let compare_commits = self
+            .remote
+            .compare(self.base_commit.as_deref().unwrap_or(""), &self.head_commit)
+            .await?;
 
         let mut join_set = JoinSet::new();
         let remote = Arc::new(self.remote);
diff --git a/src/main.rs b/src/main.rs
index 5acb0d7..01e44fa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -111,7 +111,7 @@ async fn main() -> Result<(), anyhow::Error> {
             let repo = RepoChangeset {
                 name: remote.repository.clone(),
                 remote,
-                base_commit: cli.base,
+                base_commit: Some(cli.base),
                 head_commit: cli.head,
                 changes: Vec::new(),
             };
@@ -181,8 +181,8 @@ fn find_values_yaml(
                     changes.push(RepoChangeset::new(
                         name.clone(),
                         remote::Remote::parse(&new_source.repo)?,
+                        None,
                         new_source.commit.clone(),
-                        String::new(),
                     ));
                     continue;
                 }
@@ -193,15 +193,15 @@ fn find_values_yaml(
                         changes.push(RepoChangeset::new(
                             name.clone(),
                             remote::Remote::parse(&new_source.repo)?,
+                            Some(old_source.commit.clone()),
                             new_source.commit.clone(),
-                            old_source.commit.clone(),
                         ));
                     } else {
                         changes.push(RepoChangeset::new(
                             name.clone(),
                             remote::Remote::parse(&new_source.repo)?,
+                            None,
                             new_source.commit.clone(),
-                            String::new(),
                         ));
                     }
                 }
@@ -228,7 +228,10 @@ fn print_changes(repo_changeset: &[RepoChangeset<RealClient>]) -> Result<(), any
     for change in repo_changeset {
         println_or_redirect(format!(
             "Name {} from {} moved from {} to {}",
-            change.name, change.remote.original, change.base_commit, change.head_commit,
+            change.name,
+            change.remote.original,
+            change.base_commit.as_deref().unwrap_or(""),
+            change.head_commit,
         ))?;
         println_or_redirect("| Commit link | Pull Request link | Approvals | Reviewer's verdict |".to_string())?;
         println_or_redirect("|-------------|-------------------|-----------|--------------------|".to_string())?;