Added cargo dev setup git-hook and updated cargo dev setup intellij including a remove command

CONTRIBUTING.md

@@ -115,7 +115,7 @@ To work around this, you need to have a copy of the [rustc-repo][rustc_repo] ava
 `git clone https://github.com/rust-lang/rust/`.
 Then you can run a `cargo dev` command to automatically make Clippy use the rustc-repo via path-dependencies
 which `IntelliJ Rust` will be able to understand.
-Run `cargo dev ide_setup --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
+Run `cargo dev setup intellij --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
 you just cloned.
 The command will add path-dependencies pointing towards rustc-crates inside the rustc repo to
 Clippys `Cargo.toml`s and should allow `IntelliJ Rust` to understand most of the types that Clippy uses.

clippy_dev/src/fmt.rs

@@ -86,7 +86,7 @@ pub fn run(check: bool, verbose: bool) {
             },
             CliError::RaSetupActive => {
                 eprintln!(
-                    "error: a local rustc repo is enabled as path dependency via `cargo dev ide_setup`.
+                    "error: a local rustc repo is enabled as path dependency via `cargo dev setup intellij`.
 Not formatting because that would format the local repo as well!
 Please revert the changes to Cargo.tomls first."
                 );

clippy_dev/src/lib.rs

@@ -14,9 +14,9 @@ use walkdir::WalkDir;
 
 pub mod bless;
 pub mod fmt;
-pub mod ide_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

@@ -2,8 +2,8 @@
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 
-use clap::{App, Arg, ArgMatches, SubCommand};
-use clippy_dev::{bless, fmt, ide_setup, new_lint, serve, stderr_length_check, update_lints};
+use clap::{App, AppSettings, Arg, ArgMatches, SubCommand};
+use clippy_dev::{bless, fmt, new_lint, serve, setup, stderr_length_check, update_lints};
 fn main() {
     let matches = get_clap_config();
 
@@ -36,7 +36,20 @@ fn main() {
         ("limit_stderr_length", _) => {
             stderr_length_check::check();
         },
-        ("ide_setup", Some(matches)) => ide_setup::run(matches.value_of("rustc-repo-path")),
+        ("setup", Some(sub_command)) => match sub_command.subcommand() {
+            ("intellij", Some(matches)) => setup::intellij::setup_rustc_src(
+                matches
+                    .value_of("rustc-repo-path")
+                    .expect("this field is mandatory and therefore always valid"),
+            ),
+            ("git-hook", Some(matches)) => setup::git_hook::install_hook(matches.is_present("force-override")),
+            _ => {},
+        },
+        ("remove", Some(sub_command)) => match sub_command.subcommand() {
+            ("git-hook", Some(_)) => setup::git_hook::remove_hook(),
+            ("intellij", Some(_)) => setup::intellij::remove_rustc_src(),
+            _ => {},
+        },
         ("serve", Some(matches)) => {
             let port = matches.value_of("port").unwrap().parse().unwrap();
             let lint = matches.value_of("lint");
@@ -48,6 +61,7 @@ fn main() {
 
 fn get_clap_config<'a>() -> ArgMatches<'a> {
     App::new("Clippy developer tooling")
+        .setting(AppSettings::ArgRequiredElseHelp)
         .subcommand(
             SubCommand::with_name("bless")
                 .about("bless the test output changes")
@@ -140,16 +154,42 @@ 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")
+                .setting(AppSettings::ArgRequiredElseHelp)
+                .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(
+            SubCommand::with_name("remove")
+                .about("Support for undoing changes done by the setup command")
+                .setting(AppSettings::ArgRequiredElseHelp)
+                .subcommand(SubCommand::with_name("git-hook").about("Remove any existing pre-commit git hook"))
+                .subcommand(
+                    SubCommand::with_name("intellij")
+                        .about("Removes rustc source paths added via `cargo dev setup intellij`"),
                 ),
         )
         .subcommand(

clippy_dev/src/setup/git_hook.rs

@@ -0,0 +1,79 @@
+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_FILE: &str = "util/etc/pre-commit.sh";
+const HOOK_TARGET_FILE: &str = ".git/hooks/pre-commit";
+
+pub fn install_hook(force_override: bool) {
+    if !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_FILE, HOOK_TARGET_FILE) {
+        Ok(_) => {
+            println!("info: the hook can be removed with `cargo dev remove git-hook`");
+            println!("git hook successfully installed");
+        },
+        Err(err) => eprintln!(
+            "error: unable to copy `{}` to `{}` ({})",
+            HOOK_SOURCE_FILE, HOOK_TARGET_FILE, err
+        ),
+    }
+}
+
+fn check_precondition(force_override: bool) -> bool {
+    // 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() {
+        eprintln!("error: clippy_dev was unable to find the `.git` directory");
+        return false;
+    }
+
+    // Make sure that we don't override an existing hook by accident
+    let path = Path::new(HOOK_TARGET_FILE);
+    if path.exists() {
+        if force_override {
+            return delete_git_hook_file(path);
+        }
+
+        eprintln!("error: there is already a pre-commit hook installed");
+        println!("info: use the `--force-override` flag to override the existing hook");
+        return false;
+    }
+
+    true
+}
+
+pub fn remove_hook() {
+    let path = Path::new(HOOK_TARGET_FILE);
+    if path.exists() {
+        if delete_git_hook_file(path) {
+            println!("git hook successfully removed");
+        }
+    } else {
+        println!("no pre-commit hook was found");
+    }
+}
+
+fn delete_git_hook_file(path: &Path) -> bool {
+    if let Err(err) = fs::remove_file(path) {
+        eprintln!("error: unable to delete existing pre-commit git hook ({})", err);
+        false
+    } else {
+        true
+    }
+}