Feat(bump): allow performing a simple version bump without analysing …

…commit messages

Fixes #3, for when you have a version number and a bump type, and just what to know the next version.

src/bumping.rs

@@ -4,6 +4,7 @@ use git2::Commit;
 use std::convert::TryFrom;
 use std::error::Error;
 use simple_error::SimpleError;
+use std::str::FromStr;
 
 /// Extension methods for `&str`, useful for handling conventional commits
 pub trait FirstLine<'a> {
@@ -91,6 +92,20 @@ pub trait Bump {
     fn bump(self, bt: &BumpType) -> Self;
 }
 
+impl FromStr for BumpType {
+    type Err = SimpleError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_ascii_lowercase().as_str() {
+            "none" => Ok(BumpType::None),
+            "patch" => Ok(BumpType::Patch),
+            "minor" => Ok(BumpType::Minor),
+            "major" => Ok(BumpType::Major),
+            x => Err(SimpleError::new(format!("Not a bump specification: {}", x)))
+        }
+    }
+}
+
 impl From<&str> for BumpType {
     fn from(commit_msg: &str) -> Self {
         let first_line = commit_msg.first_line();

src/main.rs

@@ -9,6 +9,7 @@ use structopt::StructOpt;
 
 use crate::bumping::{Bump, BumpType};
 use crate::changelog::ChangeLog;
+use simple_error::SimpleError;
 
 mod bumping;
 mod repo;
@@ -26,6 +27,7 @@ mod changelog;
 #[structopt(name = "what-bump")]
 struct Config {
     /// Analyse commits up to this one (exclusive)
+    #[structopt(required_unless = "bump", default_value = "")]
     up_to_revision: String,
 
     /// Current version of your software
@@ -39,11 +41,26 @@ struct Config {
     /// Also generate a changelog, and write it to this file
     #[structopt(long, short)]
     changelog: Option<PathBuf>,
+
+    /// Perform the specified version bump (you must also specify `--from`)
+    #[structopt(long, short)]
+    bump: Option<BumpType>,
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
     let config: Config = Config::from_args();
 
+    match (config.bump, &config.from) {
+        (Some(ref bump_type), Some(ref version)) => {
+            println!("{}", version.clone().bump(bump_type));
+            return Ok(());
+        },
+        (Some(_), None) => {
+            return Err(Box::new(SimpleError::new("If you specify `--bump`, you must also specify `--from`, otherwise I don't know what version to bump.")));
+        }
+        _ => (),
+    }
+
     let max_bump_type = config.path.commits_up_to(&config.up_to_revision)?
         .map(|commit| Ok(BumpType::from(commit.message().unwrap_or("<no commit message>"))))
         .max()?