chore: stop looking at git history if commit tagged

crates/git_cmd/src/lib.rs

@@ -245,10 +245,41 @@ impl Repo {
         self.git(&["log", "-1", "--pretty=format:%B"])
     }
 
+    pub fn current_commit_hash(&self) -> anyhow::Result<String> {
+        self.git(&["log", "-1", "--pretty=format:%H"])
+    }
+
+    /// Create a git tag
     pub fn tag(&self, name: &str) -> anyhow::Result<String> {
         self.git(&["tag", name])
     }
 
+    /// Get the commit hash of the given tag
+    pub fn get_tag_commit(&self, tag: &str) -> Option<String> {
+        self.git(&["rev-list", "-n", "1", tag]).ok()
+    }
+
+    /// Check if a commit comes before another one.
+    ///
+    /// ## Example
+    ///
+    /// For this git log:
+    /// ```txt
+    /// commit d6ec399b80d44bf9c4391e4a9ead8482faa9bffd
+    /// commit e880d8786cb16aa9a3f258e7503932445d708df7
+    /// ```
+    ///
+    /// `git.is_ancestor("e880d8786cb16aa9a3f258e7503932445d708df7", "d6ec399b80d44bf9c4391e4a9ead8482faa9bffd")` returns true.
+    pub fn is_ancestor(&self, maybe_ancestor_commit: &str, descendant_commit: &str) -> bool {
+        self.git(&[
+            "merge-base",
+            "--is-ancestor",
+            maybe_ancestor_commit,
+            descendant_commit,
+        ])
+        .is_ok()
+    }
+
     /// Url of the remote when the [`Repo`] was created.
     pub fn original_remote_url(&self) -> anyhow::Result<String> {
         let param = format!("remote.{}.url", self.original_remote);

crates/release_plz_core/src/next_ver.rs

@@ -27,7 +27,7 @@ use std::{
     path::{Path, PathBuf},
 };
 use tempfile::{tempdir, TempDir};
-use tracing::{debug, info, instrument};
+use tracing::{debug, info, instrument, warn};
 
 #[derive(Debug, Clone)]
 pub struct UpdateRequest {
@@ -704,17 +704,25 @@ fn get_diff(
         .map(|p| get_package_path(p, repository, &project.root))
         .collect();
     let ignored_dirs = ignored_dirs?;
+
+    let tag_commit = {
+        let git_tag = project.git_tag(&package.name, &package.version.to_string());
+        repository.get_tag_commit(&git_tag)
+    };
     loop {
         let current_commit_message = repository.current_commit_message()?;
+        let current_commit_hash = repository.current_commit_hash()?;
         if let Some(registry_package) = registry_package {
             debug!("package {} found in cargo registry", registry_package.name);
             let registry_package_path = registry_package.package_path()?;
             let are_packages_equal =
                 are_packages_equal(&package_path, registry_package_path, ignored_dirs.clone())
                     .context("cannot compare packages")?;
-            if are_packages_equal {
+            if are_packages_equal
+                || is_commit_too_old(repository, tag_commit.as_deref(), &current_commit_hash)
+            {
                 debug!(
-                    "next version calculated starting from commit after `{current_commit_message}`"
+                    "next version calculated starting from commits after `{current_commit_hash}`"
                 );
                 if diff.commits.is_empty() {
                     let are_dependencies_updated = are_toml_dependencies_updated(
@@ -759,6 +767,21 @@ fn get_diff(
     Ok(diff)
 }
 
+/// Check if commit belongs to a previous version of the package.
+fn is_commit_too_old(
+    repository: &Repo,
+    tag_commit: Option<&str>,
+    current_commit_hash: &str,
+) -> bool {
+    if let Some(tag_commit) = tag_commit.as_ref() {
+        if repository.is_ancestor(current_commit_hash, tag_commit) {
+            debug!("stopping looking at git history because the current commit ({}) is an ancestor of the commit ({}) tagged with the previous version.", current_commit_hash, tag_commit);
+            return true;
+        }
+    }
+    false
+}
+
 /// Check if release-plz should check the semver compatibility of the package.
 /// - `run_semver_check` is true if the user wants to run the semver check.
 fn should_check_semver(package: &Package, run_semver_check: bool) -> bool {