we got basic git log

Cargo.toml

@@ -28,6 +28,7 @@ git2 = "0.18.1"
 libpt = { version = "0.3.11", features = ["log"] }
 serde = { version = "1.0.195", features = ["derive"] }
 serde_yaml = "0.9.30"
+tempfile = "3.9.0"
 thiserror = "1.0.56"
 url = { version = "2.5.0", features = ["serde"] }
 

src/changelog/mod.rs

@@ -1,4 +1,4 @@
-use std::fmt::Display;
+use std::{fmt::Display, process::Command};
 
 use crate::{config::Config, error::*};
 
@@ -11,7 +11,7 @@ pub struct Changelog {
 impl Changelog {
     pub fn build(cfg: &Config) -> Result<Self> {
         if !cfg.yaml.changelog.enable {
-            return Err(ConfigError::IsDisabledButUsed("changelog").into());
+            return Err(ChangelogError::IsDisabledButUsed.into());
         }
         let git_log = Self::make_git_log(cfg)?;
         Ok(Changelog { git_log })
@@ -21,7 +21,15 @@ impl Changelog {
         if !cfg.yaml.changelog.enable {
             return Ok(None);
         }
-        Ok(Some(format!("todo")))
+        let mut cmd = Command::new("git");
+        cmd.arg("log").arg("--oneline").arg("--decorate");
+        let out = cmd.output()?;
+        // FIXME: this does not catch fancy colors
+        let buf = String::from_utf8(out.stdout).map_err(|err|{
+            ChangelogError::GitUTF8Error(err)
+        })?;
+
+        Ok(Some(buf))
     }
 }
 

src/error.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::{path::PathBuf, string::FromUtf8Error};
 
 use anyhow;
 use thiserror::Error;
@@ -18,8 +18,19 @@ pub enum Error {
     Other(#[from] anyhow::Error),
     #[error("Yaml error")]
     SerdeYaml(#[from] serde_yaml::Error),
+    #[error("Could not generate the changelog")]
+    ChangelogError(#[from] ChangelogError),
 }
 
+#[derive(Error, Debug)]
+pub enum ChangelogError {
+    #[error("changelog has 'enabled = false' in the yaml config")]
+    IsDisabledButUsed,
+    #[error("error while using `git log`, is git installed?")]
+    GitCommandError,
+    #[error("error while using `git log`, could not format stdout with utf8")]
+    GitUTF8Error(#[from] FromUtf8Error),
+}
 #[derive(Error, Debug)]
 pub enum ConfigError {
     #[error("could not find git repository")]
@@ -30,8 +41,6 @@ pub enum ConfigError {
     YamlFileIsNotFile,
     #[error("api {0:?} provides both a `pass` and a `pass_file`")]
     YamlApiAuthBothPass(ApiAuth),
-    #[error("{0} has 'enabled = false' in the yaml config")]
-    IsDisabledButUsed(&'static str),
     #[error("password provided as file, but does not exist: {0}")]
     PassFileDoesNotExist(PathBuf),
 }