From 5e6092cc6cb0fa4ae60535331eafc32e5297580b Mon Sep 17 00:00:00 2001
From: Florian Fromm <flrn.frmm@gmail.com>
Date: Mon, 3 Oct 2022 12:29:34 +0200
Subject: [PATCH] feat(config): changelog for the last n commits

Adds a additional configuration variable `limit_commits` to the
configuration struct.
`limit_commits` can be set to a positive integer number to limit the
commits contained in the generated changelog.

Also adjusts the default config file to contain `limit_commits` as a
commented out line.

Extends documentation in README.md to also cover the introduced
configuration value.

issue: https://github.com/orhun/git-cliff/issues/102
---
 README.md                                |  7 +++++++
 config/cliff.toml                        |  2 ++
 examples/limitedcommits.toml             | 21 +++++++++++++++++++++
 git-cliff-core/src/config.rs             |  4 +++-
 git-cliff-core/tests/integration_test.rs |  1 +
 git-cliff/src/changelog.rs               | 15 ++++++++-------
 git-cliff/src/lib.rs                     |  5 ++++-
 7 files changed, 46 insertions(+), 9 deletions(-)
 create mode 100644 examples/limitedcommits.toml

diff --git a/README.md b/README.md
index 6dac923c59..4c76917ce2 100644
--- a/README.md
+++ b/README.md
@@ -469,6 +469,7 @@ link_parsers = [
     { pattern = "#(\\d+)", href = "https://github.com/orhun/git-cliff/issues/$1"},
     { pattern = "RFC(\\d+)", text = "ietf-rfc$1", href = "https://datatracker.ietf.org/doc/html/rfc$1"},
 ]
+limit_commits = 42
 ```
 
 #### conventional_commits
@@ -652,6 +653,12 @@ Examples:
 - `{ pattern = "RFC(\\d+)", text = "ietf-rfc$1", href = "https://datatracker.ietf.org/doc/html/rfc$1"}`,
   - Extract mentions of IETF RFCs and generate URLs linking to them. It also rewrites the text as "ietf-rfc...".
 
+#### limit_commits
+
+`limit_commits` is a **optional** positive integer number that limits the number of included commits in the generated changelog.
+
+`limit_commits` is not part of the default configuration.
+
 ## Project Integration
 
 ### Rust
diff --git a/config/cliff.toml b/config/cliff.toml
index a4c50a0e74..33586805d3 100644
--- a/config/cliff.toml
+++ b/config/cliff.toml
@@ -66,3 +66,5 @@ ignore_tags = ""
 date_order = false
 # sort the commits inside sections by oldest/newest order
 sort_commits = "oldest"
+# limit the number of commits included in the changelog.
+# limit_commits = 42
diff --git a/examples/limitedcommits.toml b/examples/limitedcommits.toml
new file mode 100644
index 0000000000..3a4632e161
--- /dev/null
+++ b/examples/limitedcommits.toml
@@ -0,0 +1,21 @@
+# configuration file for git-cliff (0.1.0)
+
+[changelog]
+# template for the changelog body
+# https://tera.netlify.app/docs/#introduction
+body = """
+{% if version %}\
+    ## [{{ version | trim_start_matches(pat="v") }}] - {{ timestamp | date(format="%Y-%m-%d") }}\
+{% else %}\
+    ## [unreleased]\
+{% endif %}\
+{% for group, commits in commits | group_by(attribute="group") %}
+    ### {{ group | upper_first }}
+    {% for commit in commits %}\
+        - {% if commit.breaking %}[**breaking**] {% endif %}{{ commit.message | upper_first }}
+    {% endfor %}\
+{% endfor %}\n
+"""
+
+[git]
+limit_commits = 3
diff --git a/git-cliff-core/src/config.rs b/git-cliff-core/src/config.rs
index ca29cfdefb..2250b9b155 100644
--- a/git-cliff-core/src/config.rs
+++ b/git-cliff-core/src/config.rs
@@ -68,7 +68,9 @@ pub struct GitConfig {
 	/// Whether to sort tags chronologically.
 	pub date_order:               Option<bool>,
 	/// Sorting of the commits inside sections.
-	pub sort_commits:             Option<String>,
+	pub sort_commits:         Option<String>,
+	/// Limit the number of commits included in the changelog.
+	pub limit_commits:        Option<usize>,
 }
 
 /// Parser for grouping commits.
diff --git a/git-cliff-core/tests/integration_test.rs b/git-cliff-core/tests/integration_test.rs
index d9e77a4361..792021a807 100644
--- a/git-cliff-core/tests/integration_test.rs
+++ b/git-cliff-core/tests/integration_test.rs
@@ -91,6 +91,7 @@ fn generate_changelog() -> Result<()> {
 				text:    Some(String::from("$1")),
 			},
 		]),
+		limit_commits:         None,
 	};
 
 	let releases = vec![
diff --git a/git-cliff/src/changelog.rs b/git-cliff/src/changelog.rs
index 39ce6f3611..a1653b37da 100644
--- a/git-cliff/src/changelog.rs
+++ b/git-cliff/src/changelog.rs
@@ -258,13 +258,14 @@ mod test {
 					},
 				]),
 				protect_breaking_commits: None,
-				filter_commits:           Some(false),
-				tag_pattern:              None,
-				skip_tags:                Regex::new("v3.*").ok(),
-				ignore_tags:              None,
-				date_order:               Some(false),
-				sort_commits:             Some(String::from("oldest")),
-				link_parsers:             None,
+				filter_commits:        Some(false),
+				tag_pattern:           None,
+				skip_tags:             Regex::new("v3.*").ok(),
+				ignore_tags:           None,
+				date_order:            Some(false),
+				sort_commits:          Some(String::from("oldest")),
+				link_parsers:          None,
+				limit_commits:         None,
 			},
 		};
 		let test_release = Release {
diff --git a/git-cliff/src/lib.rs b/git-cliff/src/lib.rs
index 467bbaf558..6d81e43c0e 100644
--- a/git-cliff/src/lib.rs
+++ b/git-cliff/src/lib.rs
@@ -217,8 +217,11 @@ pub fn run(mut args: Opt) -> Result<()> {
 			}
 		}
 	}
-	let commits =
+	let mut commits = 
 		repository.commits(commit_range, args.include_path, args.exclude_path)?;
+	if let Some(commit_limit_value) = config.git.limit_commits {
+		commits = commits.drain(commit_limit_value..).collect();
+	}
 
 	// Update tags.
 	if let Some(tag) = args.tag {