Auto merge of rust-lang#8605 - Jarcho:remove-deps, r=xFrednet

Remove deps

This remove both `regex` and `cargo_metadata` as dependencies making `clippy_dev` compile ~3x faster (~46s -> ~16s locally). `cargo_metadata` was used to extract the `version` field from `Cargo.toml`, which is done trivially without that. `regex` was used to parse `define_clippy_lint` in `update_lints` which is now done using `rustc_lexer`. This isn't any simpler, but it compiles ~15s faster and runs ~3x faster (~2.1s -> ~0.7s locally).

The next biggest offenders to compile times are `clap` and `winapi` on windows. `clap` could be removed, but re-implementing enough is probably more work than it's worth. `winapi` is used by `opener` and `walkdir` so it's stuck there.

changelog: none

Author: bors

Cargo.toml

@@ -21,13 +21,12 @@ name = "clippy-driver"
 path = "src/driver.rs"
 
 [dependencies]
-clippy_lints = { version = "0.1", path = "clippy_lints" }
+clippy_lints = { path = "clippy_lints" }
 semver = "1.0"
-rustc_tools_util = { version = "0.2", path = "rustc_tools_util" }
+rustc_tools_util = { path = "rustc_tools_util" }
 tempfile = { version = "3.2", optional = true }
 
 [dev-dependencies]
-cargo_metadata = "0.14"
 compiletest_rs = { version = "0.7.1", features = ["tmp"] }
 tester = "0.9"
 regex = "1.5"

clippy_dev/Cargo.toml

@@ -4,15 +4,16 @@ version = "0.0.1"
 edition = "2021"
 
 [dependencies]
-bytecount = "0.6"
 clap = "2.33"
 indoc = "1.0"
 itertools = "0.10.1"
 opener = "0.5"
-regex = "1.5"
 shell-escape = "0.1"
 walkdir = "2.3"
-cargo_metadata = "0.14"
 
 [features]
 deny-warnings = []
+
+[package.metadata.rust-analyzer]
+# This package uses #[feature(rustc_private)]
+rustc_private = true

clippy_dev/src/lib.rs

@@ -1,8 +1,12 @@
+#![feature(let_else)]
 #![feature(once_cell)]
+#![feature(rustc_private)]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
 
+extern crate rustc_lexer;
+
 use std::path::PathBuf;
 
 pub mod bless;

clippy_dev/src/new_lint.rs

@@ -133,15 +133,23 @@ fn to_camel_case(name: &str) -> String {
 }
 
 fn get_stabilisation_version() -> String {
-    let mut command = cargo_metadata::MetadataCommand::new();
-    command.no_deps();
-    if let Ok(metadata) = command.exec() {
-        if let Some(pkg) = metadata.packages.iter().find(|pkg| pkg.name == "clippy") {
-            return format!("{}.{}.0", pkg.version.minor, pkg.version.patch);
-        }
+    fn parse_manifest(contents: &str) -> Option<String> {
+        let version = contents
+            .lines()
+            .filter_map(|l| l.split_once('='))
+            .find_map(|(k, v)| (k.trim() == "version").then(|| v.trim()))?;
+        let Some(("0", version)) = version.get(1..version.len() - 1)?.split_once('.') else {
+            return None;
+        };
+        let (minor, patch) = version.split_once('.')?;
+        Some(format!(
+            "{}.{}.0",
+            minor.parse::<u32>().ok()?,
+            patch.parse::<u32>().ok()?
+        ))
     }
-
-    String::from("<TODO set version(see doc/adding_lints.md)>")
+    let contents = fs::read_to_string("Cargo.toml").expect("Unable to read `Cargo.toml`");
+    parse_manifest(&contents).expect("Unable to find package version in `Cargo.toml`")
 }
 
 fn get_test_file_contents(lint_name: &str, header_commands: Option<&str>) -> String {