rust/clippy_dev/src/generate.rs

use crate::parse::cursor::Cursor;
use crate::parse::{Lint, LintData, LintPass, VecBuf};
use crate::utils::{FileUpdater, UpdateMode, UpdateStatus, update_text_region_fn};
use core::range::Range;
use itertools::Itertools;
use std::collections::HashSet;
use std::fmt::Write;
use std::path::{self, Path};

const GENERATED_FILE_COMMENT: &str = "// This file was generated by `cargo dev update_lints`.\n\
     // Use that command to update this file and do not edit by hand.\n\
     // Manual edits will be overwritten.\n\n";

const DOCS_LINK: &str = "https://rust-lang.github.io/rust-clippy/master/index.html";

impl LintData<'_> {
    #[expect(clippy::too_many_lines)]
    pub fn gen_decls(&self, update_mode: UpdateMode) {
        let mut updater = FileUpdater::default();

        let mut lints: Vec<_> = self.lints.iter().map(|(&x, y)| (x, y)).collect();
        lints.sort_by_key(|&(x, _)| x);
        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "CHANGELOG.md",
            &mut update_text_region_fn(
                "<!-- begin autogenerated links to lint list -->\n",
                "<!-- end autogenerated links to lint list -->",
                |dst| {
                    for &(lint, _) in &lints {
                        writeln!(dst, "[`{lint}`]: {DOCS_LINK}#{lint}").unwrap();
                    }
                },
            ),
        );

        let mut active = Vec::with_capacity(lints.len());
        let mut deprecated = Vec::with_capacity(lints.len() / 8);
        let mut renamed = Vec::with_capacity(lints.len() / 8);
        for &(name, lint) in &lints {
            match lint {
                Lint::Active(lint) => active.push((name, lint)),
                Lint::Deprecated(lint) => deprecated.push((name, lint)),
                Lint::Renamed(lint) => renamed.push((name, lint)),
            }
        }
        active.sort_by_key(|&(_, lint)| lint.module);

        // Round to avoid updating the readme every time a lint is added/deprecated.
        let lint_count = active.len() / 50 * 50;
        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "README.md",
            &mut update_text_region_fn("[There are over ", " lints included in this crate!]", |dst| {
                write!(dst, "{lint_count}").unwrap();
            }),
        );
        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "book/src/README.md",
            &mut update_text_region_fn("[There are over ", " lints included in this crate!]", |dst| {
                write!(dst, "{lint_count}").unwrap();
            }),
        );

        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "clippy_lints/src/deprecated_lints.rs",
            &mut |_, src, dst| {
                let mut cursor = Cursor::new(src);
                assert!(
                    cursor.find_ident("declare_with_version").is_some()
                        && cursor.find_ident("declare_with_version").is_some(),
                    "error reading deprecated lints"
                );
                dst.push_str(&src[..cursor.pos() as usize]);
                dst.push_str("! { DEPRECATED(DEPRECATED_VERSION) = [\n");
                for &(name, data) in &deprecated {
                    write!(
                        dst,
                        "    #[clippy::version = \"{}\"]\n    (\"clippy::{name}\", \"{}\"),\n",
                        data.version, data.reason,
                    )
                    .unwrap();
                }
                dst.push_str(
                    "]}\n\n\
                        #[rustfmt::skip]\n\
                        declare_with_version! { RENAMED(RENAMED_VERSION) = [\n\
                    ",
                );
                for &(name, data) in &renamed {
                    write!(
                        dst,
                        "    #[clippy::version = \"{}\"]\n    (\"clippy::{name}\", \"{}\"),\n",
                        data.version, data.new_name,
                    )
                    .unwrap();
                }
                dst.push_str("]}\n");
                UpdateStatus::from_changed(src != dst)
            },
        );
        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "tests/ui/deprecated.rs",
            &mut |_, src, dst| {
                dst.push_str(GENERATED_FILE_COMMENT);
                for &(lint, _) in &deprecated {
                    writeln!(dst, "#![warn(clippy::{lint})] //~ ERROR: lint `clippy::{lint}`").unwrap();
                }
                dst.push_str("\nfn main() {}\n");
                UpdateStatus::from_changed(src != dst)
            },
        );
        updater.update_file_checked(
            "cargo dev update_lints",
            update_mode,
            "tests/ui/rename.rs",
            &mut move |_, src, dst| {
                let mut seen_lints = HashSet::new();
                dst.push_str(GENERATED_FILE_COMMENT);
                dst.push_str("#![allow(clippy::duplicated_attributes)]\n");
                for &(_, lint) in &renamed {
                    if seen_lints.insert(lint.new_name) {
                        writeln!(dst, "#![allow({})]", lint.new_name).unwrap();
                    }
                }
                for &(lint, _) in &renamed {
                    writeln!(dst, "#![warn(clippy::{lint})] //~ ERROR: lint `clippy::{lint}`").unwrap();
                }
                dst.push_str("\nfn main() {}\n");
                UpdateStatus::from_changed(src != dst)
            },
        );
        for (crate_name, lints) in active.iter().copied().into_group_map_by(|&(_, lint)| {
            let Some(path::Component::Normal(name)) = lint.path.components().next() else {
                // All paths should start with `{crate_name}/src` when parsed from `find_lint_decls`
                panic!(
                    "internal error: can't read crate name from path `{}`",
                    lint.path.display()
                );
            };
            name
        }) {
            updater.update_file_checked(
                "cargo dev update_lints",
                update_mode,
                Path::new(crate_name).join("src/lib.rs"),
                &mut update_text_region_fn(
                    "// begin lints modules, do not remove this comment, it's used in `update_lints`\n",
                    "// end lints modules, do not remove this comment, it's used in `update_lints`",
                    |dst| {
                        let mut prev = "";
                        for &(_, lint) in &lints {
                            if lint.module != prev {
                                writeln!(dst, "mod {};", lint.module).unwrap();
                                prev = lint.module;
                            }
                        }
                    },
                ),
            );
            updater.update_file_checked(
                "cargo dev update_lints",
                update_mode,
                Path::new(crate_name).join("src/declared_lints.rs"),
                &mut |_, src, dst| {
                    dst.push_str(GENERATED_FILE_COMMENT);
                    dst.push_str("pub static LINTS: &[&::declare_clippy_lint::LintInfo] = &[\n");
                    let mut buf = String::new();
                    for &(name, lint) in &lints {
                        buf.clear();
                        buf.push_str(name);
                        buf.make_ascii_uppercase();
                        if lint.module.is_empty() {
                            writeln!(dst, "    crate::{buf}_INFO,").unwrap();
                        } else {
                            writeln!(dst, "    crate::{}::{buf}_INFO,", lint.module).unwrap();
                        }
                    }
                    dst.push_str("];\n");
                    UpdateStatus::from_changed(src != dst)
                },
            );
        }
    }
}

impl LintPass<'_> {
    pub fn gen_mac(&self, dst: &mut String) {
        let mut line_start = dst.len();
        dst.extend([self.mac.name(), "!("]);
        let has_docs = write_comment_lines(self.docs, "\n    ", dst);
        let (list_indent, list_multi_end, end) = if has_docs {
            dst.push_str("\n    ");
            line_start = dst.len() - 4;
            ("        ", "\n    ", "]\n);")
        } else {
            ("    ", "\n", "]);")
        };
        dst.push_str(self.name);
        if let Some(lt) = self.lt {
            dst.extend(["<", lt, ">"]);
        }
        dst.push_str(" => [");
        let fmt = write_list(
            self.lints.iter().copied(),
            80usize.saturating_sub(dst.len() - line_start),
            list_indent,
            dst,
        );
        if matches!(fmt, ListFmt::MultiLine) {
            dst.push_str(list_multi_end);
        }
        dst.push_str(end);
    }
}

fn write_comment_lines(s: &str, prefix: &str, dst: &mut String) -> bool {
    let mut has_doc = false;
    for line in s.split('\n') {
        let line = line.trim_start();
        if !line.is_empty() {
            has_doc = true;
            dst.extend([prefix, line]);
        }
    }
    has_doc
}

#[derive(Clone, Copy)]
enum ListFmt {
    SingleLine,
    MultiLine,
}

fn write_list<'a>(
    items: impl Iterator<Item = &'a str> + Clone,
    single_line_limit: usize,
    indent: &str,
    dst: &mut String,
) -> ListFmt {
    let len = items.clone().map(str::len).sum::<usize>();
    if len > single_line_limit {
        for item in items {
            dst.extend(["\n", indent, item, ","]);
        }
        ListFmt::MultiLine
    } else {
        let _ = write!(dst, "{}", items.format(", "));
        ListFmt::SingleLine
    }
}

/// Generates the contents of a lint's source file with all the lint and lint pass
/// declarations sorted.
pub fn gen_sorted_lints_file(
    src: &str,
    dst: &mut String,
    lints: &mut [(&str, Range<u32>)],
    passes: &mut [LintPass<'_>],
    ranges: &mut VecBuf<Range<u32>>,
) {
    ranges.with(|ranges| {
        ranges.extend(lints.iter().map(|&(_, x)| x));
        ranges.extend(passes.iter().map(|x| x.decl_range));
        ranges.sort_unstable_by_key(|x| x.start);

        lints.sort_unstable_by_key(|&(x, _)| x);
        passes.sort_by_key(|x| x.name);

        let mut ranges = ranges.iter();
        let pos = if let Some(range) = ranges.next() {
            dst.push_str(&src[..range.start as usize]);
            for &(_, range) in &*lints {
                dst.push_str(&src[range.start as usize..range.end as usize]);
                dst.push_str("\n\n");
            }
            for pass in passes {
                pass.gen_mac(dst);
                dst.push_str("\n\n");
            }
            range.end
        } else {
            dst.push_str(src);
            return;
        };

        let pos = ranges.fold(pos, |start, range| {
            let s = &src[start as usize..range.start as usize];
            dst.push_str(if s.trim_start().is_empty() {
                // Only whitespace between this and the previous item. No need to keep that.
                ""
            } else if src[..pos as usize].ends_with("\n\n")
                && let Some(s) = s.strip_prefix("\n\n")
            {
                // Empty line before and after. Remove one of them.
                s
            } else {
                // Remove only full lines unless something is in the way.
                s.strip_prefix('\n').unwrap_or(s)
            });
            range.end
        });

        // Since we always generate an empty line at the end, make sure to always skip it.
        let s = &src[pos as usize..];
        dst.push_str(s.strip_prefix('\n').map_or(s, |s| s.strip_prefix('\n').unwrap_or(s)));
    });
}