feat(changelog): support bumping the semantic version via --bump

git-cliff-core/Cargo.toml

@@ -26,6 +26,8 @@ tera = "1.19.1"
 indexmap = { version = "2.0.2", optional = true }
 toml = "0.8.2"
 lazy-regex = "3.0.2"
+next_version = "0.2.8"
+semver = "1.0.19"
 
 [dependencies.git2]
 version = "0.18.1"

git-cliff-core/src/error.rs

@@ -57,6 +57,13 @@ pub enum Error {
 	/// Error that may occur while parsing integers.
 	#[error("Failed to parse integer: `{0}`")]
 	IntParseError(#[from] std::num::TryFromIntError),
+	/// Error that may occur while parsing a SemVer version or version
+	/// requirement.
+	#[error("Semver error: `{0}`")]
+	SemverError(#[from] semver::Error),
+	/// Error that may occur when a version is not found for the next release.
+	#[error("Previous version is not found for calculating the next release.")]
+	PreviousVersionNotFound,
 }
 
 /// Result type of the core library.

git-cliff-core/src/release.rs

@@ -1,5 +1,10 @@
 use crate::commit::Commit;
-use crate::error::Result;
+use crate::error::{
+	Error,
+	Result,
+};
+use next_version::NextVersion;
+use semver::Version;
 use serde::{
 	Deserialize,
 	Serialize,
@@ -22,6 +27,26 @@ pub struct Release<'a> {
 	pub previous:  Option<Box<Release<'a>>>,
 }
 
+impl<'a> Release<'a> {
+	/// Calculates the next version based on the commits.
+	pub fn calculate_next_version(&self) -> Result<String> {
+		let version = self
+			.previous
+			.as_ref()
+			.and_then(|release| release.version.clone())
+			.ok_or_else(|| Error::PreviousVersionNotFound)?;
+		let next_version = Version::parse(version.trim_start_matches('v'))?
+			.next(
+				self.commits
+					.iter()
+					.map(|commit| commit.message.to_string())
+					.collect::<Vec<String>>(),
+			)
+			.to_string();
+		Ok(next_version)
+	}
+}
+
 /// Representation of a list of releases.
 pub struct Releases<'a>(pub &'a Vec<Release<'a>>);
 
@@ -31,3 +56,33 @@ impl<'a> Releases<'a> {
 		Ok(serde_json::to_string(self.0)?)
 	}
 }
+
+#[cfg(test)]
+mod test {
+	use super::*;
+	#[test]
+	fn bump_version() -> Result<()> {
+		for (expected_version, commits) in [
+			("1.1.0", vec!["feat: add xyz", "fix: fix xyz"]),
+			("1.0.1", vec!["fix: add xyz", "fix: aaaaaa"]),
+			("2.0.0", vec!["feat!: add xyz", "feat: zzz"]),
+		] {
+			let release = Release {
+				version:   None,
+				commits:   commits
+					.into_iter()
+					.map(|v| Commit::from(v.to_string()))
+					.collect(),
+				commit_id: None,
+				timestamp: 0,
+				previous:  Some(Box::new(Release {
+					version: Some(String::from("1.0.0")),
+					..Default::default()
+				})),
+			};
+			let next_version = release.calculate_next_version()?;
+			assert_eq!(expected_version, next_version);
+		}
+		Ok(())
+	}
+}

git-cliff/src/args.rs

@@ -142,6 +142,9 @@ pub struct Opt {
 		allow_hyphen_values = true
 	)]
 	pub tag:          Option<String>,
+	/// Bumps the version for unreleased changes.
+	#[arg(long, help_heading = Some("FLAGS"))]
+	pub bump:         bool,
 	/// Sets the template for the changelog body.
 	#[arg(
 		short,

git-cliff/src/lib.rs

@@ -229,6 +229,17 @@ fn process_repository<'a>(
 		}
 	}
 
+	// Bump the version.
+	if args.bump && releases[release_index].version.is_none() {
+		let next_version = releases[release_index].calculate_next_version()?;
+		debug!("Bumping the version to {next_version}");
+		releases[release_index].version = Some(next_version.to_string());
+		releases[release_index].timestamp = SystemTime::now()
+			.duration_since(UNIX_EPOCH)?
+			.as_secs()
+			.try_into()?;
+	}
+
 	Ok(releases)
 }
 

website/docs/usage/examples.md

@@ -17,13 +17,21 @@ Then simply create a changelog at your projects git root directory:
 git cliff
 ```
 
-Set a tag for the "unreleased" changes:
+Set a tag for the unreleased changes:
 
 ```bash
 # it doesn't have to be an existing tag
 git cliff --tag 1.0.0
 ```
 
+Calculate and set the next semantic version (i.e. _bump the version_) for the unreleased changes:
+
+```bash
+# Semver: {MAJOR}.{MINOR}.{PATCH}
+# "fix:" increments PATCH, "feat:" increments MINOR and "scope!" (breaking changes) increments MAJOR
+git cliff --bump
+```
+
 Generate a changelog for a certain part of git history:
 
 ```bash

website/docs/usage/usage.md

@@ -1,6 +1,7 @@
 ---
 sidebar_position: 3
 ---
+
 # Usage
 
 ```
@@ -13,6 +14,7 @@ git-cliff [FLAGS] [OPTIONS] [--] [RANGE]
 -h, --help        Prints help information
 -V, --version     Prints version information
 -v, --verbose...  Increases the logging verbosity
+    --bump        Bumps the version for unreleased changes
 -i, --init        Writes the default configuration file to cliff.toml
 -l, --latest      Processes the commits starting from the latest tag
     --current     Processes the commits that belong to the current tag