Add rye init option to set mercurial VCS for new project.

Usage:
```
rye init --vcs [git | mercurial]
```
Default can be configured in ~/.rye/config.toml
```
[default]
vcs = "mercurial"
```
When not specified, or when git specified, current behavior is preserved.
When mercurial is specified, a mercurial VCS is initialized unless the WD is already in a mercurial VCS, and a hgignore file is created.

rye/src/cli/init.rs

@@ -19,15 +19,15 @@ use tempfile::tempdir;
 use crate::bootstrap::ensure_self_venv;
 use crate::config::Config;
 use crate::platform::{
-    get_default_author_with_fallback, get_latest_cpython_version, get_pinnable_version,
-    get_python_version_request_from_pyenv_pin,
+    get_latest_cpython_version, get_pinnable_version, get_python_version_request_from_pyenv_pin,
 };
 use crate::pyproject::BuildSystem;
 use crate::sources::py::PythonVersionRequest;
 use crate::utils::{
-    copy_dir, escape_string, format_requirement, get_venv_python_bin, is_inside_git_work_tree,
-    CommandOutput, CopyDirOptions, IoPathContext,
+    copy_dir, escape_string, format_requirement, get_venv_python_bin, CommandOutput,
+    CopyDirOptions, IoPathContext,
 };
+use crate::vcs::ProjectVCS;
 
 /// Initialize a new or existing Python project with Rye.
 #[derive(Parser, Debug)]
@@ -83,6 +83,10 @@ pub struct Args {
     /// Turns off all output.
     #[arg(short, long, conflicts_with = "verbose")]
     quiet: bool,
+
+    /// Which VCS should be used? (defaults to git)
+    #[arg(long)]
+    vcs: Option<ProjectVCS>,
 }
 
 #[derive(Parser, Debug)]
@@ -128,9 +132,6 @@ const RUST_INIT_PY_TEMPLATE: &str = include_str!("../templates/lib/maturin/__ini
 /// Template for the Cargo.toml.
 const CARGO_TOML_TEMPLATE: &str = include_str!("../templates/lib/maturin/Cargo.toml.j2");
 
-/// Template for fresh gitignore files.
-const GITIGNORE_TEMPLATE: &str = include_str!("../templates/gitignore.j2");
-
 /// Script used for setup.py setup proxy.
 const SETUP_PY_PROXY_SCRIPT: &str = r#"
 import json, sys
@@ -199,8 +200,13 @@ pub fn execute(cmd: Args) -> Result<(), Error> {
             .unwrap_or_else(|| "unknown".into())
     }));
 
+    let project_vcs = match cmd.vcs {
+        Some(project_vcs) => project_vcs,
+        None => cfg.default_vcs().unwrap_or(ProjectVCS::Git),
+    };
+
     let version = "0.1.0";
-    let author = get_default_author_with_fallback(&dir);
+    let author = flat_author(project_vcs.get_author(&dir, cfg.default_author()));
     let license = match cmd.license {
         Some(license) => Some(license),
         None => cfg.default_license(),
@@ -326,36 +332,10 @@ pub fn execute(cmd: Args) -> Result<(), Error> {
         name_safe.insert(0, '_');
     }
 
-    // if git init is successful prepare the local git repository
-    if !is_inside_git_work_tree(&dir)
-        && Command::new("git")
-            .arg("init")
-            .current_dir(&dir)
-            .stdout(Stdio::null())
-            .stderr(Stdio::null())
-            .status()
-            .map(|status| status.success())
-            .unwrap_or(false)
-        && is_metadata_author_none
+    if !project_vcs.inside_work_tree(&dir) && project_vcs.init_dir(&dir) && is_metadata_author_none
     {
-        let new_author = get_default_author_with_fallback(&dir);
-        if author != new_author {
-            metadata.author = new_author;
-        }
-    }
-
-    let gitignore = dir.join(".gitignore");
-
-    // create a .gitignore if one is missing
-    if !gitignore.is_file() {
-        let rv = env.render_named_str(
-            "gitignore.txt",
-            GITIGNORE_TEMPLATE,
-            context! {
-                is_rust => matches!(build_system, BuildSystem::Maturin)
-            },
-        )?;
-        fs::write(&gitignore, rv).path_context(&gitignore, "failed to write .gitignore")?;
+        metadata.author = flat_author(project_vcs.get_author(&dir, cfg.default_author()));
+        project_vcs.render_templates(&dir, &env, build_system)?;
     }
 
     let rv = env.render_named_str(
@@ -457,6 +437,15 @@ pub fn execute(cmd: Args) -> Result<(), Error> {
     Ok(())
 }
 
+fn flat_author(author: (Option<String>, Option<String>)) -> Option<(String, String)> {
+    match author {
+        (Some(name), Some(email)) => Some((name, email)),
+        (Some(name), None) => Some((name, "[email protected]".to_string())),
+        (None, Some(email)) => Some(("Unknown".to_string(), email)),
+        _ => None,
+    }
+}
+
 #[derive(Default)]
 struct Metadata {
     name: Option<String>,

rye/src/config.rs

@@ -12,6 +12,7 @@ use crate::platform::{get_app_dir, get_latest_cpython_version};
 use crate::pyproject::{BuildSystem, SourceRef, SourceRefType};
 use crate::sources::py::PythonVersionRequest;
 use crate::utils::{toml, IoPathContext};
+use crate::vcs::ProjectVCS;
 
 static CONFIG: Mutex<Option<Arc<Config>>> = Mutex::new(None);
 static AUTHOR_REGEX: Lazy<Regex> =
@@ -126,6 +127,18 @@ impl Config {
         }
     }
 
+    pub fn default_vcs(&self) -> Option<ProjectVCS> {
+        match self
+            .doc
+            .get("default")
+            .and_then(|x| x.get("vcs"))
+            .and_then(|x| x.as_str())
+        {
+            Some(vcs) => vcs.parse::<ProjectVCS>().ok(),
+            None => None,
+        }
+    }
+
     /// Returns the default license
     pub fn default_license(&self) -> Option<String> {
         self.doc

rye/src/main.rs

@@ -19,6 +19,7 @@ mod sources;
 mod sync;
 mod utils;
 mod uv;
+mod vcs;
 
 static SHOW_CONTINUE_PROMPT: AtomicBool = AtomicBool::new(false);
 static DISABLE_CTRLC_HANDLER: AtomicBool = AtomicBool::new(false);

rye/src/platform.rs

@@ -1,11 +1,9 @@
 use std::path::{Path, PathBuf};
-use std::process::{Command, Stdio};
 use std::sync::Mutex;
 use std::{env, fs};
 
 use anyhow::{anyhow, Context, Error};
 
-use crate::config::Config;
 use crate::pyproject::latest_available_python_version;
 use crate::sources::py::{PythonVersion, PythonVersionRequest};
 use crate::utils::IoPathContext;
@@ -177,39 +175,6 @@ pub fn list_known_toolchains() -> Result<Vec<(PythonVersion, PathBuf)>, Error> {
     Ok(rv)
 }
 
-/// Returns the default author from git or the config.
-pub fn get_default_author_with_fallback(dir: &PathBuf) -> Option<(String, String)> {
-    let (mut name, mut email) = Config::current().default_author();
-    let is_name_none = name.is_none();
-    let is_email_none = email.is_none();
-
-    if let Ok(rv) = Command::new("git")
-        .arg("config")
-        .arg("--get-regexp")
-        .current_dir(dir)
-        .arg("^user.(name|email)$")
-        .stdout(Stdio::piped())
-        .output()
-    {
-        for line in std::str::from_utf8(&rv.stdout).ok()?.lines() {
-            match line.split_once(' ') {
-                Some((key, value)) if key == "user.email" && is_email_none => {
-                    email = Some(value.to_string());
-                }
-                Some((key, value)) if key == "user.name" && is_name_none => {
-                    name = Some(value.to_string());
-                }
-                _ => {}
-            }
-        }
-    }
-
-    Some((
-        name?,
-        email.unwrap_or_else(|| "[email protected]".into()),
-    ))
-}
-
 /// Reads the current `.python-version` file.
 pub fn get_python_version_request_from_pyenv_pin(root: &Path) -> Option<PythonVersionRequest> {
     let mut here = root.to_owned();

rye/src/templates/hgignore.j2

@@ -0,0 +1,15 @@
+# python generated files
+__pycache__/
+.*\.py[oc]
+build/
+dist/
+wheels/
+.*\.egg-info
+
+{%- if is_rust %}
+# Rust
+target/
+{%- endif %}
+
+# venv
+\.venv

rye/src/utils/mod.rs

@@ -392,18 +392,6 @@ pub fn get_venv_python_bin(venv_path: &Path) -> PathBuf {
     py
 }
 
-pub fn is_inside_git_work_tree(dir: &PathBuf) -> bool {
-    Command::new("git")
-        .arg("rev-parse")
-        .arg("--is-inside-work-tree")
-        .current_dir(dir)
-        .stdout(Stdio::null())
-        .stderr(Stdio::null())
-        .status()
-        .map(|status| status.success())
-        .unwrap_or(false)
-}
-
 /// Returns a success exit status.
 pub fn success_status() -> ExitStatus {
     #[cfg(windows)]
@@ -576,19 +564,3 @@ mod test_expand_env_vars {
         assert_eq!("This string has an env var: Example value", output);
     }
 }
-
-#[cfg(test)]
-mod test_is_inside_git_work_tree {
-    use std::path::PathBuf;
-
-    use super::is_inside_git_work_tree;
-    #[test]
-    fn test_is_inside_git_work_tree_true() {
-        assert!(is_inside_git_work_tree(&PathBuf::from(".")));
-    }
-
-    #[test]
-    fn test_is_inside_git_work_tree_false() {
-        assert!(!is_inside_git_work_tree(&PathBuf::from("/")));
-    }
-}