Don't create a separate bin for format hook

docs/dev/README.md

@@ -55,7 +55,7 @@ We use Travis for CI. Most of the things, including formatting, are checked by
 be green as well. We use bors-ng to enforce the [not rocket
 science](https://graydon2.dreamwidth.org/1597.html) rule.
 
-You can run `cargo format-hook` to install git-hook to run rustfmt on commit.
+You can run `cargo xtask install-pre-commit-hook` to install git-hook to run rustfmt on commit.
 
 # Code organization
 

xtask/src/bin/pre-commit.rs

@@ -1,31 +0,0 @@
-//! FIXME: write short doc here
-
-use std::process::Command;
-
-use xtask::{codegen::Mode, project_root, run, run_rustfmt, Result};
-
-fn main() -> Result<()> {
-    run_rustfmt(Mode::Overwrite)?;
-    update_staged()
-}
-
-fn update_staged() -> Result<()> {
-    let root = project_root();
-    let output = Command::new("git")
-        .arg("diff")
-        .arg("--diff-filter=MAR")
-        .arg("--name-only")
-        .arg("--cached")
-        .current_dir(&root)
-        .output()?;
-    if !output.status.success() {
-        anyhow::bail!(
-            "`git diff --diff-filter=MAR --name-only --cached` exited with {}",
-            output.status
-        );
-    }
-    for line in String::from_utf8(output.stdout)?.lines() {
-        run(&format!("git update-index --add {}", root.join(line).to_string_lossy()), ".")?;
-    }
-    Ok(())
-}

xtask/src/help.rs

@@ -10,7 +10,7 @@ FLAGS:
 
 SUBCOMMANDS:
     format
-    format-hook
+    install-pre-commit-hook
     fuzz-tests
     codegen
     install

xtask/src/lib.rs

@@ -83,19 +83,12 @@ pub fn install_rustfmt() -> Result<()> {
     run(&format!("rustup component add rustfmt --toolchain {}", TOOLCHAIN), ".")
 }
 
-pub fn install_format_hook() -> Result<()> {
-    let result_path = Path::new(if cfg!(windows) {
-        "./.git/hooks/pre-commit.exe"
-    } else {
-        "./.git/hooks/pre-commit"
-    });
+pub fn install_pre_commit_hook() -> Result<()> {
+    let result_path =
+        PathBuf::from(format!("./.git/hooks/pre-commit{}", std::env::consts::EXE_SUFFIX));
     if !result_path.exists() {
-        run("cargo build --package xtask --bin pre-commit", ".")?;
-        if cfg!(windows) {
-            fs::copy("./target/debug/pre-commit.exe", result_path)?;
-        } else {
-            fs::copy("./target/debug/pre-commit", result_path)?;
-        }
+        let me = std::env::current_exe()?;
+        fs::copy(me, result_path)?;
     } else {
         Err(IoError::new(ErrorKind::AlreadyExists, "Git hook already created"))?;
     }
@@ -150,6 +143,27 @@ pub fn run_fuzzer() -> Result<()> {
     run("rustup run nightly -- cargo fuzz run parser", "./crates/ra_syntax")
 }
 
+pub fn reformat_staged_files() -> Result<()> {
+    let root = project_root();
+    let output = Command::new("git")
+        .arg("diff")
+        .arg("--diff-filter=MAR")
+        .arg("--name-only")
+        .arg("--cached")
+        .current_dir(&root)
+        .output()?;
+    if !output.status.success() {
+        anyhow::bail!(
+            "`git diff --diff-filter=MAR --name-only --cached` exited with {}",
+            output.status
+        );
+    }
+    for line in String::from_utf8(output.stdout)?.lines() {
+        run(&format!("git update-index --add {}", root.join(line).to_string_lossy()), ".")?;
+    }
+    Ok(())
+}
+
 fn do_run<F>(cmdline: &str, dir: &str, mut f: F) -> Result<Output>
 where
     F: FnMut(&mut Command),

xtask/src/main.rs

@@ -16,7 +16,8 @@ use pico_args::Arguments;
 use std::{env, path::PathBuf};
 use xtask::{
     codegen::{self, Mode},
-    install_format_hook, run, run_clippy, run_fuzzer, run_rustfmt, run_with_output, Cmd, Result,
+    install_pre_commit_hook, reformat_staged_files, run, run_clippy, run_fuzzer, run_rustfmt,
+    run_with_output, Cmd, Result,
 };
 
 // Latest stable, feel free to send a PR if this lags behind.
@@ -36,6 +37,10 @@ struct ServerOpt {
 }
 
 fn main() -> Result<()> {
+    if std::env::args().next().map(|it| it.contains("pre-commit")) == Some(true) {
+        return reformat_staged_files();
+    }
+
     let subcommand = match std::env::args_os().nth(1) {
         None => {
             eprintln!("{}", help::GLOBAL_HELP);
@@ -81,12 +86,12 @@ fn main() -> Result<()> {
             }
             run_rustfmt(Mode::Overwrite)?
         }
-        "format-hook" => {
+        "install-pre-commit-hook" => {
             if matches.contains(["-h", "--help"]) {
                 help::print_no_param_subcommand_help(&subcommand);
                 return Ok(());
             }
-            install_format_hook()?
+            install_pre_commit_hook()?
         }
         "lint" => {
             if matches.contains(["-h", "--help"]) {