chore(core): make git2 optional

git-cliff-core/Cargo.toml

@@ -10,6 +10,10 @@ keywords = ["changelog", "generator", "conventional", "commit"]
 edition = "2021"
 rust-version = "1.64.0"
 
+[features]
+default = ["repo"]
+repo = ["dep:git2"]
+
 [dependencies]
 glob.workspace = true
 regex.workspace = true
@@ -26,6 +30,7 @@ lazy-regex = "2.5.0"
 [dependencies.git2]
 version = "0.17.1"
 default-features = false
+optional = true
 
 [dependencies.config]
 version = "0.13.3"

git-cliff-core/src/commit.rs

@@ -9,6 +9,7 @@ use crate::error::{
 	Error as AppError,
 	Result,
 };
+#[cfg(feature = "repo")]
 use git2::{
 	Commit as GitCommit,
 	Signature as CommitSignature,
@@ -84,6 +85,7 @@ pub struct Signature {
 	pub timestamp: i64,
 }
 
+#[cfg(feature = "repo")]
 impl<'a> From<CommitSignature<'a>> for Signature {
 	fn from(signature: CommitSignature<'a>) -> Self {
 		Self {
@@ -142,6 +144,7 @@ impl<'a> From<String> for Commit<'a> {
 	}
 }
 
+#[cfg(feature = "repo")]
 impl<'a> From<&GitCommit<'a>> for Commit<'a> {
 	fn from(commit: &GitCommit<'a>) -> Self {
 		Commit {

git-cliff-core/src/error.rs

@@ -11,6 +11,7 @@ pub enum Error {
 	#[error("UTF-8 error: `{0}`")]
 	Utf8Error(#[from] std::str::Utf8Error),
 	/// Error variant that represents errors coming out of libgit2.
+	#[cfg(feature = "repo")]
 	#[error("Git error: `{0}`")]
 	GitError(#[from] git2::Error),
 	/// Error that may occur while parsing the config file.

git-cliff-core/src/lib.rs

@@ -15,6 +15,7 @@ pub mod embed;
 pub mod error;
 /// Common release type.
 pub mod release;
+#[cfg(feature = "repo")]
 /// Git repository.
 pub mod repo;
 /// Template engine.