Added cargo dev setup git-hook

clippy_dev/src/lib.rs

@@ -14,9 +14,9 @@ use walkdir::WalkDir;
 
 pub mod bless;
 pub mod fmt;
-pub mod setup;
 pub mod new_lint;
 pub mod serve;
+pub mod setup;
 pub mod stderr_length_check;
 pub mod update_lints;
 

clippy_dev/src/main.rs

@@ -3,7 +3,7 @@
 #![warn(rust_2018_idioms, unused_lifetimes)]
 
 use clap::{App, Arg, ArgMatches, SubCommand};
-use clippy_dev::{bless, fmt, setup, new_lint, serve, stderr_length_check, update_lints};
+use clippy_dev::{bless, fmt, new_lint, serve, setup, stderr_length_check, update_lints};
 fn main() {
     let matches = get_clap_config();
 
@@ -36,7 +36,11 @@ fn main() {
         ("limit_stderr_length", _) => {
             stderr_length_check::check();
         },
-        ("ide_setup", Some(matches)) => setup::intellij::run(matches.value_of("rustc-repo-path")),
+        ("setup", Some(sub_command)) => match sub_command.subcommand() {
+            ("intellij", Some(matches)) => setup::intellij::run(matches.value_of("rustc-repo-path")),
+            ("git-hook", Some(matches)) => setup::git_hook::run(matches.is_present("force-override")),
+            _ => {},
+        },
         ("serve", Some(matches)) => {
             let port = matches.value_of("port").unwrap().parse().unwrap();
             let lint = matches.value_of("lint");
@@ -140,16 +144,31 @@ fn get_clap_config<'a>() -> ArgMatches<'a> {
                 .about("Ensures that stderr files do not grow longer than a certain amount of lines."),
         )
         .subcommand(
-            SubCommand::with_name("ide_setup")
-                .about("Alter dependencies so Intellij Rust can find rustc internals")
-                .arg(
-                    Arg::with_name("rustc-repo-path")
-                        .long("repo-path")
-                        .short("r")
-                        .help("The path to a rustc repo that will be used for setting the dependencies")
-                        .takes_value(true)
-                        .value_name("path")
-                        .required(true),
+            SubCommand::with_name("setup")
+                .about("Support for setting up your personal development environment")
+                .subcommand(
+                    SubCommand::with_name("intellij")
+                        .about("Alter dependencies so Intellij Rust can find rustc internals")
+                        .arg(
+                            Arg::with_name("rustc-repo-path")
+                                .long("repo-path")
+                                .short("r")
+                                .help("The path to a rustc repo that will be used for setting the dependencies")
+                                .takes_value(true)
+                                .value_name("path")
+                                .required(true),
+                        ),
+                )
+                .subcommand(
+                    SubCommand::with_name("git-hook")
+                        .about("Add a pre-commit git hook that formats your code to make it look pretty")
+                        .arg(
+                            Arg::with_name("force-override")
+                                .long("force-override")
+                                .short("f")
+                                .help("Forces the override of an existing git pre-commit hook")
+                                .required(false),
+                        ),
                 ),
         )
         .subcommand(

clippy_dev/src/setup/git_hook.rs

@@ -0,0 +1,61 @@
+use std::fs;
+use std::path::Path;
+
+/// Rusts setup uses `git rev-parse --git-common-dir` to get the root directory of the repo.
+/// I've decided against this for the sake of simplicity and to make sure that it doesn't install
+/// the hook if `clippy_dev` would be used in the rust tree. The hook also references this tool
+/// for formatting and should therefor only be used in a normal clone of clippy
+const REPO_GIT_DIR: &str = ".git";
+const HOOK_SOURCE_PATH: &str = "util/etc/pre-commit.sh";
+const HOOK_TARGET_PATH: &str = ".git/hooks/pre-commit";
+
+pub fn run(force_override: bool) {
+    if let Err(_) = check_precondition(force_override) {
+        return;
+    }
+
+    // So a little bit of a funny story. Git on unix requires the pre-commit file
+    // to have the `execute` permission to be set. The Rust functions for modifying
+    // these flags doesn't seem to work when executed with normal user permissions.
+    //
+    // However, there is a little hack that is also being used by Rust itself in their
+    // setup script. Git saves the `execute` flag when syncing files. This means
+    // that we can check in a file with execution permissions and the sync it to create
+    // a file with the flag set. We then copy this file here. The copy function will also
+    // include the `execute` permission.
+    match fs::copy(HOOK_SOURCE_PATH, HOOK_TARGET_PATH) {
+        Ok(_) => println!("Git hook successfully installed :)"),
+        Err(err) => println!(
+            "error: unable to copy `{}` to `{}` ({})",
+            HOOK_SOURCE_PATH, HOOK_TARGET_PATH, err
+        ),
+    }
+}
+
+fn check_precondition(force_override: bool) -> Result<(), ()> {
+    // Make sure that we can find the git repository
+    let git_path = Path::new(REPO_GIT_DIR);
+    if !git_path.exists() || !git_path.is_dir() {
+        println!("error: clippy_dev was unable to find the `.git` directory");
+        return Err(());
+    }
+
+    // Make sure that we don't override an existing hook by accident
+    let path = Path::new(HOOK_TARGET_PATH);
+    if path.exists() {
+        if !force_override {
+            println!("warn: The found `.git` directory already has a commit hook");
+        }
+
+        if force_override || super::ask_yes_no_question("Do you want to override it?") {
+            if fs::remove_file(path).is_err() {
+                println!("error: unable to delete existing pre-commit git hook");
+                return Err(());
+            }
+        } else {
+            return Err(());
+        }
+    }
+
+    Ok(())
+}

clippy_dev/src/setup/mod.rs

@@ -1 +1,30 @@
-pub mod intellij;
+use std::io::{self, Write};
+pub mod git_hook;
+pub mod intellij;
+
+/// This function will asked the user the given question and wait for user input
+/// either `true` for yes and `false` for no.
+fn ask_yes_no_question(question: &str) -> bool {
+    // This code was proudly stolen from rusts bootstrapping tool.
+
+    fn ask_with_result(question: &str) -> io::Result<bool> {
+        let mut input = String::new();
+        Ok(loop {
+            print!("{}: [y/N] ", question);
+            io::stdout().flush()?;
+            input.clear();
+            io::stdin().read_line(&mut input)?;
+            break match input.trim().to_lowercase().as_str() {
+                "y" | "yes" => true,
+                "n" | "no" | "" => false,
+                _ => {
+                    println!("error: unrecognized option '{}'", input.trim());
+                    println!("note: press Ctrl+C to exit");
+                    continue;
+                },
+            };
+        })
+    }
+
+    ask_with_result(question).unwrap_or_default()
+}

util/etc/pre-commit.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+cargo dev fmt