Auto merge of #13180 - Jarcho:deprecated_shrink, r=flip1995

Simplify lint deprecation

A couple of small changes:
* A few deprecations were changed to renames. They all had a message similar to "this lint has been replaced by ..." which is just describing a rename.
* The website and warning message are now the same. The website description was usually just a wordier version that contained no extra information. This can be worked around if needed, but I don't think that will happen.
* The legacy deprecations have been removed. rustc should handle this since it already suggests adding the `clippy::` for all lints (deprecated or not) when they're used without it. It wouldn't be a problem to add them back in.
* The website no longer has a "view source" link for deprecated lints since they're no longer read from the HIR tree. I could store the line number, but the link seems totally useless for these lints.

This came up as part of separating the internal lints into their own crate. Both the metadata collector and the lint registration code needs access to the deprecated and renamed lists. This form lets all the deprecations be a separate crate.

r? `@flip1995`

changelog: none

3 files changed, 96 insertions, 230 deletions

diff --git a/clippy_dev/src/main.rs b/clippy_dev/src/main.rs
index 366b52b25df..db7287aac21 100644
--- a/clippy_dev/src/main.rs
+++ b/clippy_dev/src/main.rs
@@ -74,7 +74,7 @@ fn main() {
             new_name,
             uplift,
         } => update_lints::rename(&old_name, new_name.as_ref().unwrap_or(&old_name), uplift),
-        DevCommand::Deprecate { name, reason } => update_lints::deprecate(&name, reason.as_deref()),
+        DevCommand::Deprecate { name, reason } => update_lints::deprecate(&name, &reason),
     }
 }
 
@@ -223,7 +223,7 @@ enum DevCommand {
         name: String,
         #[arg(long, short)]
         /// The reason for deprecation
-        reason: Option<String>,
+        reason: String,
     },
 }
 
diff --git a/clippy_dev/src/serve.rs b/clippy_dev/src/serve.rs
index 16f286faf57..19560b31fd3 100644
--- a/clippy_dev/src/serve.rs
+++ b/clippy_dev/src/serve.rs
@@ -3,6 +3,12 @@ use std::process::Command;
 use std::time::{Duration, SystemTime};
 use std::{env, thread};
 
+#[cfg(windows)]
+const PYTHON: &str = "python";
+
+#[cfg(not(windows))]
+const PYTHON: &str = "python3";
+
 /// # Panics
 ///
 /// Panics if the python commands could not be spawned
@@ -23,7 +29,7 @@ pub fn run(port: u16, lint: Option<String>) -> ! {
         }
         if let Some(url) = url.take() {
             thread::spawn(move || {
-                Command::new("python3")
+                Command::new(PYTHON)
                     .arg("-m")
                     .arg("http.server")
                     .arg(port.to_string())
diff --git a/clippy_dev/src/update_lints.rs b/clippy_dev/src/update_lints.rs
index 45353901c98..880e4c3d7a0 100644
--- a/clippy_dev/src/update_lints.rs
+++ b/clippy_dev/src/update_lints.rs
@@ -1,13 +1,12 @@
 use crate::clippy_project_root;
 use aho_corasick::AhoCorasickBuilder;
-use indoc::writedoc;
 use itertools::Itertools;
 use rustc_lexer::{tokenize, unescape, LiteralKind, TokenKind};
 use std::collections::{HashMap, HashSet};
 use std::ffi::OsStr;
 use std::fmt::{self, Write};
 use std::fs::{self, OpenOptions};
-use std::io::{self, Read, Seek, SeekFrom, Write as _};
+use std::io::{self, Read, Seek, Write as _};
 use std::ops::Range;
 use std::path::{Path, PathBuf};
 use walkdir::{DirEntry, WalkDir};
@@ -77,12 +76,8 @@ fn generate_lint_files(
             for lint in usable_lints
                 .iter()
                 .map(|l| &*l.name)
-                .chain(deprecated_lints.iter().map(|l| &*l.name))
-                .chain(
-                    renamed_lints
-                        .iter()
-                        .map(|l| l.old_name.strip_prefix("clippy::").unwrap_or(&l.old_name)),
-                )
+                .chain(deprecated_lints.iter().filter_map(|l| l.name.strip_prefix("clippy::")))
+                .chain(renamed_lints.iter().filter_map(|l| l.old_name.strip_prefix("clippy::")))
                 .sorted()
             {
                 writeln!(res, "[`{lint}`]: {DOCS_LINK}#{lint}").unwrap();
@@ -108,11 +103,6 @@ fn generate_lint_files(
         update_mode,
         &gen_declared_lints(internal_lints.iter(), usable_lints.iter()),
     );
-    process_file(
-        "clippy_lints/src/lib.deprecated.rs",
-        update_mode,
-        &gen_deprecated(deprecated_lints),
-    );
 
     let content = gen_deprecated_lints_test(deprecated_lints);
     process_file("tests/ui/deprecated.rs", update_mode, &content);
@@ -205,7 +195,7 @@ pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
             let ext = f.path().extension();
             (ext == Some(OsStr::new("rs")) || ext == Some(OsStr::new("fixed")))
                 && name != Some(OsStr::new("rename.rs"))
-                && name != Some(OsStr::new("renamed_lints.rs"))
+                && name != Some(OsStr::new("deprecated_lints.rs"))
         })
     {
         rewrite_file(file.path(), |s| {
@@ -213,6 +203,19 @@ pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
         });
     }
 
+    let version = crate::new_lint::get_stabilization_version();
+    rewrite_file(Path::new("clippy_lints/src/deprecated_lints.rs"), |s| {
+        insert_at_marker(
+            s,
+            "// end renamed lints. used by `cargo dev rename_lint`",
+            &format!(
+                "#[clippy::version = \"{version}\"]\n    \
+                (\"{}\", \"{}\"),\n    ",
+                lint.old_name, lint.new_name,
+            ),
+        )
+    });
+
     renamed_lints.push(lint);
     renamed_lints.sort_by(|lhs, rhs| {
         lhs.new_name
@@ -222,11 +225,6 @@ pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
             .then_with(|| lhs.old_name.cmp(&rhs.old_name))
     });
 
-    write_file(
-        Path::new("clippy_lints/src/renamed_lints.rs"),
-        &gen_renamed_lints_list(&renamed_lints),
-    );
-
     if uplift {
         write_file(Path::new("tests/ui/rename.rs"), &gen_renamed_lints_test(&renamed_lints));
         println!(
@@ -293,7 +291,8 @@ pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
 
         // Don't change `clippy_utils/src/renamed_lints.rs` here as it would try to edit the lint being
         // renamed.
-        for (_, file) in clippy_lints_src_files().filter(|(rel_path, _)| rel_path != OsStr::new("renamed_lints.rs")) {
+        for (_, file) in clippy_lints_src_files().filter(|(rel_path, _)| rel_path != OsStr::new("deprecated_lints.rs"))
+        {
             rewrite_file(file.path(), |s| replace_ident_like(s, replacements));
         }
 
@@ -304,7 +303,6 @@ pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
     println!("note: `cargo uitest` still needs to be run to update the test results");
 }
 
-const DEFAULT_DEPRECATION_REASON: &str = "default deprecation note";
 /// Runs the `deprecate` command
 ///
 /// This does the following:
@@ -314,33 +312,16 @@ const DEFAULT_DEPRECATION_REASON: &str = "default deprecation note";
 /// # Panics
 ///
 /// If a file path could not read from or written to
-pub fn deprecate(name: &str, reason: Option<&str>) {
-    fn finish(
-        (lints, mut deprecated_lints, renamed_lints): (Vec<Lint>, Vec<DeprecatedLint>, Vec<RenamedLint>),
-        name: &str,
-        reason: &str,
-    ) {
-        deprecated_lints.push(DeprecatedLint {
-            name: name.to_string(),
-            reason: reason.to_string(),
-            declaration_range: Range::default(),
-        });
-
-        generate_lint_files(UpdateMode::Change, &lints, &deprecated_lints, &renamed_lints);
-        println!("info: `{name}` has successfully been deprecated");
-
-        if reason == DEFAULT_DEPRECATION_REASON {
-            println!("note: the deprecation reason must be updated in `clippy_lints/src/deprecated_lints.rs`");
-        }
-        println!("note: you must run `cargo uitest` to update the test results");
-    }
-
-    let reason = reason.unwrap_or(DEFAULT_DEPRECATION_REASON);
-    let name_lower = name.to_lowercase();
-    let name_upper = name.to_uppercase();
+pub fn deprecate(name: &str, reason: &str) {
+    let prefixed_name = if name.starts_with("clippy::") {
+        name.to_owned()
+    } else {
+        format!("clippy::{name}")
+    };
+    let stripped_name = &prefixed_name[8..];
 
-    let (mut lints, deprecated_lints, renamed_lints) = gather_all();
-    let Some(lint) = lints.iter().find(|l| l.name == name_lower) else {
+    let (mut lints, mut deprecated_lints, renamed_lints) = gather_all();
+    let Some(lint) = lints.iter().find(|l| l.name == stripped_name) else {
         eprintln!("error: failed to find lint `{name}`");
         return;
     };
@@ -357,13 +338,27 @@ pub fn deprecate(name: &str, reason: Option<&str>) {
 
     let deprecated_lints_path = &*clippy_project_root().join("clippy_lints/src/deprecated_lints.rs");
 
-    if remove_lint_declaration(&name_lower, &mod_path, &mut lints).unwrap_or(false) {
-        declare_deprecated(&name_upper, deprecated_lints_path, reason).unwrap();
-        finish((lints, deprecated_lints, renamed_lints), name, reason);
-        return;
-    }
+    if remove_lint_declaration(stripped_name, &mod_path, &mut lints).unwrap_or(false) {
+        let version = crate::new_lint::get_stabilization_version();
+        rewrite_file(deprecated_lints_path, |s| {
+            insert_at_marker(
+                s,
+                "// end deprecated lints. used by `cargo dev deprecate_lint`",
+                &format!("#[clippy::version = \"{version}\"]\n    (\"{prefixed_name}\", \"{reason}\"),\n    ",),
+            )
+        });
+
+        deprecated_lints.push(DeprecatedLint {
+            name: prefixed_name,
+            reason: reason.into(),
+        });
 
-    eprintln!("error: lint not found");
+        generate_lint_files(UpdateMode::Change, &lints, &deprecated_lints, &renamed_lints);
+        println!("info: `{name}` has successfully been deprecated");
+        println!("note: you must run `cargo uitest` to update the test results");
+    } else {
+        eprintln!("error: lint not found");
+    }
 }
 
 fn remove_lint_declaration(name: &str, path: &Path, lints: &mut Vec<Lint>) -> io::Result<bool> {
@@ -465,37 +460,6 @@ fn remove_lint_declaration(name: &str, path: &Path, lints: &mut Vec<Lint>) -> io
     Ok(false)
 }
 
-fn declare_deprecated(name: &str, path: &Path, reason: &str) -> io::Result<()> {
-    let mut file = OpenOptions::new().write(true).open(path)?;
-
-    file.seek(SeekFrom::End(0))?;
-
-    let version = crate::new_lint::get_stabilization_version();
-    let deprecation_reason = if reason == DEFAULT_DEPRECATION_REASON {
-        "TODO"
-    } else {
-        reason
-    };
-
-    writedoc!(
-        file,
-        "
-
-        declare_deprecated_lint! {{
-            /// ### What it does
-            /// Nothing. This lint has been deprecated.
-            ///
-            /// ### Deprecation reason
-            /// {deprecation_reason}
-            #[clippy::version = \"{version}\"]
-            pub {name},
-            \"{reason}\"
-        }}
-
-        "
-    )
-}
-
 /// Replace substrings if they aren't bordered by identifier characters. Returns `None` if there
 /// were no replacements.
 fn replace_ident_like(contents: &str, replacements: &[(&str, &str)]) -> Option<String> {
@@ -604,14 +568,12 @@ impl Lint {
 struct DeprecatedLint {
     name: String,
     reason: String,
-    declaration_range: Range<usize>,
 }
 impl DeprecatedLint {
-    fn new(name: &str, reason: &str, declaration_range: Range<usize>) -> Self {
+    fn new(name: &str, reason: &str) -> Self {
         Self {
-            name: name.to_lowercase(),
+            name: remove_line_splices(name),
             reason: remove_line_splices(reason),
-            declaration_range,
         }
     }
 }
@@ -629,28 +591,6 @@ impl RenamedLint {
     }
 }
 
-/// Generates the `register_removed` code
-#[must_use]
-fn gen_deprecated(lints: &[DeprecatedLint]) -> String {
-    let mut output = GENERATED_FILE_COMMENT.to_string();
-    output.push_str("{\n");
-    for lint in lints {
-        let _: fmt::Result = write!(
-            output,
-            concat!(
-                "    store.register_removed(\n",
-                "        \"clippy::{}\",\n",
-                "        \"{}\",\n",
-                "    );\n"
-            ),
-            lint.name, lint.reason,
-        );
-    }
-    output.push_str("}\n");
-
-    output
-}
-
 /// Generates the code for registering lints
 #[must_use]
 fn gen_declared_lints<'a>(
@@ -680,7 +620,7 @@ fn gen_declared_lints<'a>(
 fn gen_deprecated_lints_test(lints: &[DeprecatedLint]) -> String {
     let mut res: String = GENERATED_FILE_COMMENT.into();
     for lint in lints {
-        writeln!(res, "#![warn(clippy::{})]", lint.name).unwrap();
+        writeln!(res, "#![warn({})] //~ ERROR: lint `{}`", lint.name, lint.name).unwrap();
     }
     res.push_str("\nfn main() {}\n");
     res
@@ -699,27 +639,13 @@ fn gen_renamed_lints_test(lints: &[RenamedLint]) -> String {
     seen_lints.clear();
     for lint in lints {
         if seen_lints.insert(&lint.old_name) {
-            writeln!(res, "#![warn({})]", lint.old_name).unwrap();
+            writeln!(res, "#![warn({})] //~ ERROR: lint `{}`", lint.old_name, lint.old_name).unwrap();
         }
     }
     res.push_str("\nfn main() {}\n");
     res
 }
 
-fn gen_renamed_lints_list(lints: &[RenamedLint]) -> String {
-    const HEADER: &str = "\
-        // This file is managed by `cargo dev rename_lint`. Prefer using that when possible.\n\n\
-        #[rustfmt::skip]\n\
-        pub static RENAMED_LINTS: &[(&str, &str)] = &[\n";
-
-    let mut res = String::from(HEADER);
-    for lint in lints {
-        writeln!(res, "    (\"{}\", \"{}\"),", lint.old_name, lint.new_name).unwrap();
-    }
-    res.push_str("];\n");
-    res
-}
-
 /// Gathers all lints defined in `clippy_lints/src`
 fn gather_all() -> (Vec<Lint>, Vec<DeprecatedLint>, Vec<RenamedLint>) {
     let mut lints = Vec::with_capacity(1000);
@@ -744,10 +670,10 @@ fn gather_all() -> (Vec<Lint>, Vec<DeprecatedLint>, Vec<RenamedLint>) {
             module.strip_suffix(".rs").unwrap_or(&module)
         };
 
-        match module {
-            "deprecated_lints" => parse_deprecated_contents(&contents, &mut deprecated_lints),
-            "renamed_lints" => parse_renamed_contents(&contents, &mut renamed_lints),
-            _ => parse_contents(&contents, module, &mut lints),
+        if module == "deprecated_lints" {
+            parse_deprecated_contents(&contents, &mut deprecated_lints, &mut renamed_lints);
+        } else {
+            parse_contents(&contents, module, &mut lints);
         }
     }
     (lints, deprecated_lints, renamed_lints)
@@ -848,54 +774,37 @@ fn parse_contents(contents: &str, module: &str, lints: &mut Vec<Lint>) {
 }
 
 /// Parse a source file looking for `declare_deprecated_lint` macro invocations.
-fn parse_deprecated_contents(contents: &str, lints: &mut Vec<DeprecatedLint>) {
-    let mut offset = 0usize;
-    let mut iter = tokenize(contents).map(|t| {
-        let range = offset..offset + t.len as usize;
-        offset = range.end;
-
-        LintDeclSearchResult {
-            token_kind: t.kind,
-            content: &contents[range.clone()],
-            range,
-        }
-    });
+fn parse_deprecated_contents(contents: &str, deprecated: &mut Vec<DeprecatedLint>, renamed: &mut Vec<RenamedLint>) {
+    let Some((_, contents)) = contents.split_once("\ndeclare_with_version! { DEPRECATED") else {
+        return;
+    };
+    let Some((deprecated_src, renamed_src)) = contents.split_once("\ndeclare_with_version! { RENAMED") else {
+        return;
+    };
 
-    while let Some(LintDeclSearchResult { range, .. }) = iter.find(
-        |LintDeclSearchResult {
-             token_kind, content, ..
-         }| token_kind == &TokenKind::Ident && *content == "declare_deprecated_lint",
-    ) {
-        let start = range.start;
+    for line in deprecated_src.lines() {
+        let mut offset = 0usize;
+        let mut iter = tokenize(line).map(|t| {
+            let range = offset..offset + t.len as usize;
+            offset = range.end;
 
-        let mut iter = iter.by_ref().filter(|LintDeclSearchResult { ref token_kind, .. }| {
-            !matches!(token_kind, TokenKind::Whitespace | TokenKind::LineComment { .. })
+            LintDeclSearchResult {
+                token_kind: t.kind,
+                content: &line[range.clone()],
+                range,
+            }
         });
+
         let (name, reason) = match_tokens!(
             iter,
-            // !{
-            Bang OpenBrace
-            // #[clippy::version = "version"]
-            Pound OpenBracket Ident Colon Colon Ident Eq Literal{..} CloseBracket
-            // pub LINT_NAME,
-            Ident Ident(name) Comma
-            // "description"
-            Literal{kind: LiteralKind::Str{..},..}(reason)
+            // ("old_name",
+            Whitespace OpenParen Literal{kind: LiteralKind::Str{..},..}(name) Comma
+            // "new_name"),
+            Whitespace Literal{kind: LiteralKind::Str{..},..}(reason) CloseParen Comma
         );
-
-        if let Some(LintDeclSearchResult {
-            token_kind: TokenKind::CloseBrace,
-            range,
-            ..
-        }) = iter.next()
-        {
-            lints.push(DeprecatedLint::new(name, reason, start..range.end));
-        }
+        deprecated.push(DeprecatedLint::new(name, reason));
     }
-}
-
-fn parse_renamed_contents(contents: &str, lints: &mut Vec<RenamedLint>) {
-    for line in contents.lines() {
+    for line in renamed_src.lines() {
         let mut offset = 0usize;
         let mut iter = tokenize(line).map(|t| {
             let range = offset..offset + t.len as usize;
@@ -915,7 +824,7 @@ fn parse_renamed_contents(contents: &str, lints: &mut Vec<RenamedLint>) {
             // "new_name"),
             Whitespace Literal{kind: LiteralKind::Str{..},..}(new_name) CloseParen Comma
         );
-        lints.push(RenamedLint::new(old_name, new_name));
+        renamed.push(RenamedLint::new(old_name, new_name));
     }
 }
 
@@ -1015,6 +924,12 @@ fn panic_file(error: io::Error, name: &Path, action: &str) -> ! {
     panic!("failed to {action} file `{}`: {error}", name.display())
 }
 
+fn insert_at_marker(text: &str, marker: &str, new_text: &str) -> Option<String> {
+    let i = text.find(marker)?;
+    let (pre, post) = text.split_at(i);
+    Some([pre, new_text, post].into_iter().collect())
+}
+
 fn rewrite_file(path: &Path, f: impl FnOnce(&str) -> Option<String>) {
     let mut file = OpenOptions::new()
         .write(true)
@@ -1085,31 +1000,6 @@ mod tests {
     }
 
     #[test]
-    fn test_parse_deprecated_contents() {
-        static DEPRECATED_CONTENTS: &str = r#"
-            /// some doc comment
-            declare_deprecated_lint! {
-                #[clippy::version = "I'm a version"]
-                pub SHOULD_ASSERT_EQ,
-                "`assert!()` will be more flexible with RFC 2011"
-            }
-        "#;
-
-        let mut result = Vec::new();
-        parse_deprecated_contents(DEPRECATED_CONTENTS, &mut result);
-        for r in &mut result {
-            r.declaration_range = Range::default();
-        }
-
-        let expected = vec![DeprecatedLint::new(
-            "should_assert_eq",
-            "\"`assert!()` will be more flexible with RFC 2011\"",
-            Range::default(),
-        )];
-        assert_eq!(expected, result);
-    }
-
-    #[test]
     fn test_usable_lints() {
         let lints = vec![
             Lint::new(
@@ -1177,34 +1067,4 @@ mod tests {
         );
         assert_eq!(expected, Lint::by_lint_group(lints.into_iter()));
     }
-
-    #[test]
-    fn test_gen_deprecated() {
-        let lints = vec![
-            DeprecatedLint::new(
-                "should_assert_eq",
-                "\"has been superseded by should_assert_eq2\"",
-                Range::default(),
-            ),
-            DeprecatedLint::new("another_deprecated", "\"will be removed\"", Range::default()),
-        ];
-
-        let expected = GENERATED_FILE_COMMENT.to_string()
-            + &[
-                "{",
-                "    store.register_removed(",
-                "        \"clippy::should_assert_eq\",",
-                "        \"has been superseded by should_assert_eq2\",",
-                "    );",
-                "    store.register_removed(",
-                "        \"clippy::another_deprecated\",",
-                "        \"will be removed\",",
-                "    );",
-                "}",
-            ]
-            .join("\n")
-            + "\n";
-
-        assert_eq!(expected, gen_deprecated(&lints));
-    }
 }