feat(cli): generate changelog from JSON context

git-cliff-core/src/changelog.rs

@@ -18,7 +18,10 @@ use crate::remote::github::GitHubClient;
 use crate::remote::gitlab::GitLabClient;
 use crate::template::Template;
 use std::collections::HashMap;
-use std::io::Write;
+use std::io::{
+	Read,
+	Write,
+};
 use std::time::{
 	SystemTime,
 	UNIX_EPOCH,
@@ -39,8 +42,16 @@ pub struct Changelog<'a> {
 impl<'a> Changelog<'a> {
 	/// Constructs a new instance.
 	pub fn new(releases: Vec<Release<'a>>, config: &'a Config) -> Result<Self> {
+		let mut changelog = Changelog::build(releases, config)?;
+		changelog.process_commits();
+		changelog.process_releases();
+		changelog.add_remote_data()?;
+		Ok(changelog)
+	}
+
+	fn build(releases: Vec<Release<'a>>, config: &'a Config) -> Result<Self> {
 		let trim = config.changelog.trim.unwrap_or(true);
-		let mut changelog = Self {
+		Ok(Self {
 			releases,
 			header_template: match &config.changelog.header {
 				Some(header) => Some(Template::new(header.to_string(), trim)?),
@@ -61,11 +72,12 @@ impl<'a> Changelog<'a> {
 			},
 			config,
 			additional_context: HashMap::new(),
-		};
-		changelog.process_commits();
-		changelog.process_releases();
-		changelog.add_remote_data()?;
-		Ok(changelog)
+		})
+	}
+
+	/// Constructs an instance from a serialized context object.
+	pub fn from_context<R: Read>(input: &mut R, config: &'a Config) -> Result<Self> {
+		Changelog::build(serde_json::from_reader(input)?, config)
 	}
 
 	/// Adds a key value pair to the template context.

git-cliff-core/src/commit.rs

@@ -37,7 +37,7 @@ static SHA1_REGEX: Lazy<Regex> = lazy_regex!(r#"^\b([a-f0-9]{40})\b (.*)$"#);
 
 /// Object representing a link
 #[derive(Debug, Clone, Eq, PartialEq, Deserialize, Serialize)]
-#[serde(rename_all = "camelCase")]
+#[serde(rename_all(serialize = "camelCase"))]
 pub struct Link {
 	/// Text of the link.
 	pub text: String,
@@ -98,7 +98,7 @@ impl<'a> From<CommitSignature<'a>> for Signature {
 
 /// Common commit object that is parsed from a repository.
 #[derive(Debug, Default, Clone, PartialEq, Deserialize)]
-#[serde(rename_all = "camelCase")]
+#[serde(rename_all(serialize = "camelCase"))]
 pub struct Commit<'a> {
 	/// Commit ID.
 	pub id:            String,

git-cliff-core/src/release.rs

@@ -24,7 +24,7 @@ use serde::{
 
 /// Representation of a release.
 #[derive(Default, Debug, Clone, PartialEq, Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
+#[serde(rename_all(serialize = "camelCase"))]
 pub struct Release<'a> {
 	/// Release version, git tag.
 	pub version:    Option<String>,

git-cliff/src/args.rs

@@ -231,6 +231,15 @@ pub struct Opt {
 	/// Prints changelog context as JSON.
 	#[arg(short = 'x', long, help_heading = Some("FLAGS"))]
 	pub context:          bool,
+	/// Generates changelog from a JSON context.
+	#[arg(
+        long,
+        help_heading = Some("FLAGS"),
+	    value_name = "PATH",
+	    value_parser = Opt::parse_dir,
+	    num_args = 0..=1,
+    )]
+	pub from_context:     Option<PathBuf>,
 	/// Strips the given parts from the changelog.
 	#[arg(short, long, value_name = "PART", value_enum)]
 	pub strip:            Option<Strip>,

git-cliff/src/lib.rs

@@ -496,49 +496,59 @@ pub fn run(mut args: Opt) -> Result<()> {
 	if args.ignore_tags.is_some() {
 		config.git.ignore_tags.clone_from(&args.ignore_tags);
 	}
-	// Process the repositories.
-	let repositories = args.repository.clone().unwrap_or(vec![env::current_dir()?]);
-	let mut releases = Vec::<Release>::new();
-	for repository in repositories {
-		// Skip commits
-		let mut skip_list = Vec::new();
-		let ignore_file = repository.join(IGNORE_FILE);
-		if ignore_file.exists() {
-			let contents = fs::read_to_string(ignore_file)?;
-			let commits = contents
-				.lines()
-				.filter(|v| !(v.starts_with('#') || v.trim().is_empty()))
-				.map(|v| String::from(v.trim()))
-				.collect::<Vec<String>>();
-			skip_list.extend(commits);
-		}
-		if let Some(ref skip_commit) = args.skip_commit {
-			skip_list.extend(skip_commit.clone());
-		}
-		if let Some(commit_parsers) = config.git.commit_parsers.as_mut() {
-			for sha1 in skip_list {
-				commit_parsers.insert(0, CommitParser {
-					sha: Some(sha1.to_string()),
-					skip: Some(true),
-					..Default::default()
-				})
-			}
-		}
-
-		// Process the repository.
-		let repository = Repository::init(repository)?;
-		releases.extend(process_repository(
-			Box::leak(Box::new(repository)),
-			&mut config,
-			&args,
-		)?);
-	}
 
 	// Process commits and releases for the changelog.
 	if let Some(BumpOption::Specific(bump_type)) = args.bump {
 		config.bump.bump_type = Some(bump_type)
 	}
-	let mut changelog = Changelog::new(releases, &config)?;
+
+	let mut changelog: Changelog = if let Some(context_path) = args.from_context {
+		if context_path == Path::new("-") {
+			Changelog::from_context(&mut io::stdin(), &config)?
+		} else {
+			Changelog::from_context(&mut File::open(context_path)?, &config)?
+		}
+	} else {
+		// Process the repositories.
+		let repositories =
+			args.repository.clone().unwrap_or(vec![env::current_dir()?]);
+		let mut releases = Vec::<Release>::new();
+		for repository in repositories {
+			// Skip commits
+			let mut skip_list = Vec::new();
+			let ignore_file = repository.join(IGNORE_FILE);
+			if ignore_file.exists() {
+				let contents = fs::read_to_string(ignore_file)?;
+				let commits = contents
+					.lines()
+					.filter(|v| !(v.starts_with('#') || v.trim().is_empty()))
+					.map(|v| String::from(v.trim()))
+					.collect::<Vec<String>>();
+				skip_list.extend(commits);
+			}
+			if let Some(ref skip_commit) = args.skip_commit {
+				skip_list.extend(skip_commit.clone());
+			}
+			if let Some(commit_parsers) = config.git.commit_parsers.as_mut() {
+				for sha1 in skip_list {
+					commit_parsers.insert(0, CommitParser {
+						sha: Some(sha1.to_string()),
+						skip: Some(true),
+						..Default::default()
+					})
+				}
+			}
+
+			// Process the repository.
+			let repository = Repository::init(repository)?;
+			releases.extend(process_repository(
+				Box::leak(Box::new(repository)),
+				&mut config,
+				&args,
+			)?);
+		}
+		Changelog::new(releases, &config)?
+	};
 
 	// Print the result.
 	let mut out: Box<dyn io::Write> = if let Some(path) = &args.output {