clippy_dev/src/new_lint.rs

   1 use crate::clippy_project_root;
   2 use indoc::indoc;
   3 use std::fmt::Write as _;
   4 use std::fs::{self, OpenOptions};
   5 use std::io::prelude::*;
   6 use std::io::{self, ErrorKind};
   7 use std::path::{Path, PathBuf};
   8
   9 struct LintData<'a> {
  10     pass: &'a str,
  11     name: &'a str,
  12     category: &'a str,
  13     project_root: PathBuf,
  14 }
  15
  16 trait Context {
  17     fn context<C: AsRef<str>>(self, text: C) -> Self;
  18 }
  19
  20 impl<T> Context for io::Result<T> {
  21     fn context<C: AsRef<str>>(self, text: C) -> Self {
  22         match self {
  23             Ok(t) => Ok(t),
  24             Err(e) => {
  25                 let message = format!("{}: {}", text.as_ref(), e);
  26                 Err(io::Error::new(ErrorKind::Other, message))
  27             },
  28         }
  29     }
  30 }
  31
  32 /// Creates the files required to implement and test a new lint and runs `update_lints`.
  33 ///
  34 /// # Errors
  35 ///
  36 /// This function errors out if the files couldn't be created or written to.
  37 pub fn create(pass: Option<&str>, lint_name: Option<&str>, category: Option<&str>, msrv: bool) -> io::Result<()> {
  38     let lint = LintData {
  39         pass: pass.expect("`pass` argument is validated by clap"),
  40         name: lint_name.expect("`name` argument is validated by clap"),
  41         category: category.expect("`category` argument is validated by clap"),
  42         project_root: clippy_project_root(),
  43     };
  44
  45     create_lint(&lint, msrv).context("Unable to create lint implementation")?;
  46     create_test(&lint).context("Unable to create a test for the new lint")?;
  47     add_lint(&lint, msrv).context("Unable to add lint to clippy_lints/src/lib.rs")
  48 }
  49
  50 fn create_lint(lint: &LintData<'_>, enable_msrv: bool) -> io::Result<()> {
  51     let lint_contents = get_lint_file_contents(lint, enable_msrv);
  52
  53     let lint_path = format!("clippy_lints/src/{}.rs", lint.name);
  54     write_file(lint.project_root.join(&lint_path), lint_contents.as_bytes())
  55 }
  56
  57 fn create_test(lint: &LintData<'_>) -> io::Result<()> {
  58     fn create_project_layout<P: Into<PathBuf>>(lint_name: &str, location: P, case: &str, hint: &str) -> io::Result<()> {
  59         let mut path = location.into().join(case);
  60         fs::create_dir(&path)?;
  61         write_file(path.join("Cargo.toml"), get_manifest_contents(lint_name, hint))?;
  62
  63         path.push("src");
  64         fs::create_dir(&path)?;
  65         let header = format!("// compile-flags: --crate-name={}", lint_name);
  66         write_file(path.join("main.rs"), get_test_file_contents(lint_name, Some(&header)))?;
  67
  68         Ok(())
  69     }
  70
  71     if lint.category == "cargo" {
  72         let relative_test_dir = format!("tests/ui-cargo/{}", lint.name);
  73         let test_dir = lint.project_root.join(relative_test_dir);
  74         fs::create_dir(&test_dir)?;
  75
  76         create_project_layout(lint.name, &test_dir, "fail", "Content that triggers the lint goes here")?;
  77         create_project_layout(lint.name, &test_dir, "pass", "This file should not trigger the lint")
  78     } else {
  79         let test_path = format!("tests/ui/{}.rs", lint.name);
  80         let test_contents = get_test_file_contents(lint.name, None);
  81         write_file(lint.project_root.join(test_path), test_contents)
  82     }
  83 }
  84
  85 fn add_lint(lint: &LintData<'_>, enable_msrv: bool) -> io::Result<()> {
  86     let path = "clippy_lints/src/lib.rs";
  87     let mut lib_rs = fs::read_to_string(path).context("reading")?;
  88
  89     let comment_start = lib_rs.find("// add lints here,").expect("Couldn't find comment");
  90
  91     let new_lint = if enable_msrv {
  92         format!(
  93             "store.register_{lint_pass}_pass(move || Box::new({module_name}::{camel_name}::new(msrv)));\n    ",
  94             lint_pass = lint.pass,
  95             module_name = lint.name,
  96             camel_name = to_camel_case(lint.name),
  97         )
  98     } else {
  99         format!(
 100             "store.register_{lint_pass}_pass(|| Box::new({module_name}::{camel_name}));\n    ",
 101             lint_pass = lint.pass,
 102             module_name = lint.name,
 103             camel_name = to_camel_case(lint.name),
 104         )
 105     };
 106
 107     lib_rs.insert_str(comment_start, &new_lint);
 108
 109     fs::write(path, lib_rs).context("writing")
 110 }
 111
 112 fn write_file<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> io::Result<()> {
 113     fn inner(path: &Path, contents: &[u8]) -> io::Result<()> {
 114         OpenOptions::new()
 115             .write(true)
 116             .create_new(true)
 117             .open(path)?
 118             .write_all(contents)
 119     }
 120
 121     inner(path.as_ref(), contents.as_ref()).context(format!("writing to file: {}", path.as_ref().display()))
 122 }
 123
 124 fn to_camel_case(name: &str) -> String {
 125     name.split('_')
 126         .map(|s| {
 127             if s.is_empty() {
 128                 String::from("")
 129             } else {
 130                 [&s[0..1].to_uppercase(), &s[1..]].concat()
 131             }
 132         })
 133         .collect()
 134 }
 135
 136 fn get_stabilisation_version() -> String {
 137     fn parse_manifest(contents: &str) -> Option<String> {
 138         let version = contents
 139             .lines()
 140             .filter_map(|l| l.split_once('='))
 141             .find_map(|(k, v)| (k.trim() == "version").then(|| v.trim()))?;
 142         let Some(("0", version)) = version.get(1..version.len() - 1)?.split_once('.') else {
 143             return None;
 144         };
 145         let (minor, patch) = version.split_once('.')?;
 146         Some(format!(
 147             "{}.{}.0",
 148             minor.parse::<u32>().ok()?,
 149             patch.parse::<u32>().ok()?
 150         ))
 151     }
 152     let contents = fs::read_to_string("Cargo.toml").expect("Unable to read `Cargo.toml`");
 153     parse_manifest(&contents).expect("Unable to find package version in `Cargo.toml`")
 154 }
 155
 156 fn get_test_file_contents(lint_name: &str, header_commands: Option<&str>) -> String {
 157     let mut contents = format!(
 158         indoc! {"
 159             #![warn(clippy::{})]
 160
 161             fn main() {{
 162                 // test code goes here
 163             }}
 164         "},
 165         lint_name
 166     );
 167
 168     if let Some(header) = header_commands {
 169         contents = format!("{}\n{}", header, contents);
 170     }
 171
 172     contents
 173 }
 174
 175 fn get_manifest_contents(lint_name: &str, hint: &str) -> String {
 176     format!(
 177         indoc! {r#"
 178             # {}
 179
 180             [package]
 181             name = "{}"
 182             version = "0.1.0"
 183             publish = false
 184
 185             [workspace]
 186         "#},
 187         hint, lint_name
 188     )
 189 }
 190
 191 fn get_lint_file_contents(lint: &LintData<'_>, enable_msrv: bool) -> String {
 192     let mut result = String::new();
 193
 194     let (pass_type, pass_lifetimes, pass_import, context_import) = match lint.pass {
 195         "early" => ("EarlyLintPass", "", "use rustc_ast::ast::*;", "EarlyContext"),
 196         "late" => ("LateLintPass", "<'_>", "use rustc_hir::*;", "LateContext"),
 197         _ => {
 198             unreachable!("`pass_type` should only ever be `early` or `late`!");
 199         },
 200     };
 201
 202     let version = get_stabilisation_version();
 203     let lint_name = lint.name;
 204     let category = lint.category;
 205     let name_camel = to_camel_case(lint.name);
 206     let name_upper = lint_name.to_uppercase();
 207
 208     result.push_str(&if enable_msrv {
 209         format!(
 210             indoc! {"
 211                 use clippy_utils::msrvs;
 212                 {pass_import}
 213                 use rustc_lint::{{{context_import}, {pass_type}, LintContext}};
 214                 use rustc_semver::RustcVersion;
 215                 use rustc_session::{{declare_tool_lint, impl_lint_pass}};
 216
 217             "},
 218             pass_type = pass_type,
 219             pass_import = pass_import,
 220             context_import = context_import,
 221         )
 222     } else {
 223         format!(
 224             indoc! {"
 225                 {pass_import}
 226                 use rustc_lint::{{{context_import}, {pass_type}}};
 227                 use rustc_session::{{declare_lint_pass, declare_tool_lint}};
 228
 229             "},
 230             pass_import = pass_import,
 231             pass_type = pass_type,
 232             context_import = context_import
 233         )
 234     });
 235
 236     let _ = write!(
 237         result,
 238         indoc! {r#"
 239             declare_clippy_lint! {{
 240                 /// ### What it does
 241                 ///
 242                 /// ### Why is this bad?
 243                 ///
 244                 /// ### Example
 245                 /// ```rust
 246                 /// // example code where clippy issues a warning
 247                 /// ```
 248                 /// Use instead:
 249                 /// ```rust
 250                 /// // example code which does not raise clippy warning
 251                 /// ```
 252                 #[clippy::version = "{version}"]
 253                 pub {name_upper},
 254                 {category},
 255                 "default lint description"
 256             }}
 257         "#},
 258         version = version,
 259         name_upper = name_upper,
 260         category = category,
 261     );
 262
 263     result.push_str(&if enable_msrv {
 264         format!(
 265             indoc! {"
 266                 pub struct {name_camel} {{
 267                     msrv: Option<RustcVersion>,
 268                 }}
 269
 270                 impl {name_camel} {{
 271                     #[must_use]
 272                     pub fn new(msrv: Option<RustcVersion>) -> Self {{
 273                         Self {{ msrv }}
 274                     }}
 275                 }}
 276
 277                 impl_lint_pass!({name_camel} => [{name_upper}]);
 278
 279                 impl {pass_type}{pass_lifetimes} for {name_camel} {{
 280                     extract_msrv_attr!({context_import});
 281                 }}
 282
 283                 // TODO: Add MSRV level to `clippy_utils/src/msrvs.rs` if needed.
 284                 // TODO: Add MSRV test to `tests/ui/min_rust_version_attr.rs`.
 285                 // TODO: Update msrv config comment in `clippy_lints/src/utils/conf.rs`
 286             "},
 287             pass_type = pass_type,
 288             pass_lifetimes = pass_lifetimes,
 289             name_upper = name_upper,
 290             name_camel = name_camel,
 291             context_import = context_import,
 292         )
 293     } else {
 294         format!(
 295             indoc! {"
 296                 declare_lint_pass!({name_camel} => [{name_upper}]);
 297
 298                 impl {pass_type}{pass_lifetimes} for {name_camel} {{}}
 299             "},
 300             pass_type = pass_type,
 301             pass_lifetimes = pass_lifetimes,
 302             name_upper = name_upper,
 303             name_camel = name_camel,
 304         )
 305     });
 306
 307     result
 308 }
 309
 310 #[test]
 311 fn test_camel_case() {
 312     let s = "a_lint";
 313     let s2 = to_camel_case(s);
 314     assert_eq!(s2, "ALint");
 315
 316     let name = "a_really_long_new_lint";
 317     let name2 = to_camel_case(name);
 318     assert_eq!(name2, "AReallyLongNewLint");
 319
 320     let name3 = "lint__name";
 321     let name4 = to_camel_case(name3);
 322     assert_eq!(name4, "LintName");
 323 }