Add rustfix::apply_suggestions_separately

crates/rustfix/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustfix"
-version = "0.8.4"
+version = "0.8.5"
 authors = [
     "Pascal Hertleif <killercup@gmail.com>",
     "Oliver Schneider <oli-obk@users.noreply.github.com>",

crates/rustfix/src/lib.rs

@@ -213,6 +213,7 @@ pub fn collect_suggestions<S: ::std::hash::BuildHasher>(
 /// 1. Feeds the source of a file to [`CodeFix::new`].
 /// 2. Calls [`CodeFix::apply`] to apply suggestions to the source code.
 /// 3. Calls [`CodeFix::finish`] to get the "fixed" code.
+#[derive(Clone)]
 pub struct CodeFix {
     data: replace::Data,
     /// Whether or not the data has been modified.
@@ -230,12 +231,18 @@ impl CodeFix {
 
     /// Applies a suggestion to the code.
     pub fn apply(&mut self, suggestion: &Suggestion) -> Result<(), Error> {
-        for sol in &suggestion.solutions {
-            for r in &sol.replacements {
-                self.data
-                    .replace_range(r.snippet.range.clone(), r.replacement.as_bytes())?;
-                self.modified = true;
-            }
+        for solution in &suggestion.solutions {
+            self.apply_solution(solution)?;
+        }
+        Ok(())
+    }
+
+    /// Applies an individual solution from a [`Suggestion`]
+    pub fn apply_solution(&mut self, solution: &Solution) -> Result<(), Error> {
+        for r in &solution.replacements {
+            self.data
+                .replace_range(r.snippet.range.clone(), r.replacement.as_bytes())?;
+            self.modified = true;
         }
         Ok(())
     }
@@ -252,6 +259,10 @@ impl CodeFix {
 }
 
 /// Applies multiple `suggestions` to the given `code`.
+///
+/// When a diagnostic has multiple `help` subdiagnostics that offer suggestions
+/// they are merged together into a single output, to apply them separately see
+/// [`apply_suggestions_separately`]
 pub fn apply_suggestions(code: &str, suggestions: &[Suggestion]) -> Result<String, Error> {
     let mut already_applied = HashSet::new();
     let mut fix = CodeFix::new(code);
@@ -270,3 +281,33 @@ pub fn apply_suggestions(code: &str, suggestions: &[Suggestion]) -> Result<Strin
     }
     fix.finish()
 }
+
+/// Applies multiple `suggestions` to the given `code`.
+///
+/// When a diagnostic has multiple subdiagnostics that offer suggestions they
+/// are applied separately, each output being the result of only applying the
+/// Nth suggestion.
+///
+/// Currently individual subdiagnostics with multiple suggestions are treated
+/// the same as a single multi-span suggestion, see
+/// [rust-lang/rust#53934](https://github.com/rust-lang/rust/issues/53934).
+pub fn apply_suggestions_separately(
+    code: &str,
+    suggestions: &[Suggestion],
+) -> Result<Vec<String>, Error> {
+    let max_solutions = suggestions
+        .iter()
+        .map(|suggestion| suggestion.solutions.len())
+        .max()
+        .unwrap_or_default();
+    let mut already_applied = HashSet::new();
+    let mut fixes = vec![CodeFix::new(code); max_solutions];
+    for suggestion in suggestions.iter().rev() {
+        for (solution, fix) in suggestion.solutions.iter().zip(&mut fixes) {
+            if already_applied.insert(solution) {
+                fix.apply_solution(solution)?;
+            }
+        }
+    }
+    fixes.iter().map(CodeFix::finish).collect()
+}

crates/rustfix/tests/parse_and_replace.rs

@@ -23,7 +23,7 @@
 #![allow(clippy::disallowed_methods, clippy::print_stdout, clippy::print_stderr)]
 
 use anyhow::{anyhow, ensure, Context, Error};
-use rustfix::apply_suggestions;
+use rustfix::{apply_suggestions, apply_suggestions_separately};
 use std::collections::HashSet;
 use std::env;
 use std::ffi::OsString;
@@ -33,8 +33,12 @@ use std::process::{Command, Output};
 use tempfile::tempdir;
 use tracing::{debug, info, warn};
 
-mod fixmode {
-    pub const EVERYTHING: &str = "yolo";
+#[derive(Clone, Copy)]
+enum ReplaceMode {
+    /// Combine suggestions into a single `.fixed` file with [`apply_suggestions`]
+    Combined,
+    /// Create a separate `.fixed` file per suggestion with [`apply_suggestions_separately`]
+    Separate,
 }
 
 mod settings {
@@ -151,23 +155,16 @@ fn diff(expected: &str, actual: &str) -> String {
     res
 }
 
-fn test_rustfix_with_file<P: AsRef<Path>>(file: P, mode: &str) -> Result<(), Error> {
+fn test_rustfix_with_file<P: AsRef<Path>>(file: P, replace_mode: ReplaceMode) -> Result<(), Error> {
     let file: &Path = file.as_ref();
     let json_file = file.with_extension("json");
-    let fixed_file = file.with_extension("fixed.rs");
-
-    let filter_suggestions = if mode == fixmode::EVERYTHING {
-        rustfix::Filter::Everything
-    } else {
-        rustfix::Filter::MachineApplicableOnly
-    };
 
     debug!("next up: {:?}", file);
     let code = fs::read_to_string(file)?;
     let errors =
         compile_and_get_json_errors(file).context(format!("could compile {}", file.display()))?;
     let suggestions =
-        rustfix::get_suggestions_from_json(&errors, &HashSet::new(), filter_suggestions)
+        rustfix::get_suggestions_from_json(&errors, &HashSet::new(), rustfix::Filter::Everything)
             .context("could not load suggestions")?;
 
     if std::env::var(settings::RECORD_JSON).is_ok() {
@@ -179,9 +176,12 @@ fn test_rustfix_with_file<P: AsRef<Path>>(file: P, mode: &str) -> Result<(), Err
             "could not load json fixtures for {}",
             file.display()
         ))?;
-        let expected_suggestions =
-            rustfix::get_suggestions_from_json(&expected_json, &HashSet::new(), filter_suggestions)
-                .context("could not load expected suggestions")?;
+        let expected_suggestions = rustfix::get_suggestions_from_json(
+            &expected_json,
+            &HashSet::new(),
+            rustfix::Filter::Everything,
+        )
+        .context("could not load expected suggestions")?;
 
         ensure!(
             expected_suggestions == suggestions,
@@ -193,28 +193,52 @@ fn test_rustfix_with_file<P: AsRef<Path>>(file: P, mode: &str) -> Result<(), Err
         );
     }
 
-    let fixed = apply_suggestions(&code, &suggestions)
-        .context(format!("could not apply suggestions to {}", file.display()))?
-        .replace('\r', "");
+    let bless = std::env::var_os(settings::BLESS)
+        .is_some_and(|bless_name| bless_name == file.file_name().unwrap());
 
-    if std::env::var(settings::RECORD_FIXED_RUST).is_ok() {
-        fs::write(file.with_extension("recorded.rs"), &fixed)?;
+    if bless {
+        std::fs::write(&json_file, &errors)?;
     }
 
-    if let Some(bless_name) = std::env::var_os(settings::BLESS) {
-        if bless_name == file.file_name().unwrap() {
-            std::fs::write(&json_file, &errors)?;
-            std::fs::write(&fixed_file, &fixed)?;
+    match replace_mode {
+        ReplaceMode::Combined => {
+            let fixed = apply_suggestions(&code, &suggestions)
+                .context(format!("could not apply suggestions to {}", file.display()))?
+                .replace('\r', "");
+            check_fixed_file(fixed, file.with_extension("fixed.rs"), bless)?;
         }
+        ReplaceMode::Separate => {
+            let fixes = apply_suggestions_separately(&code, &suggestions)
+                .context(format!("could not apply suggestions to {}", file.display()))?;
+            for (i, fixed) in fixes.iter().enumerate() {
+                check_fixed_file(
+                    fixed.replace('\r', ""),
+                    file.with_extension(format!("fixed.{i}.rs")),
+                    bless,
+                )?;
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn check_fixed_file(fixed: String, fixed_file: PathBuf, bless: bool) -> Result<(), Error> {
+    if std::env::var(settings::RECORD_FIXED_RUST).is_ok() {
+        fs::write(fixed_file.with_extension("recorded.rs"), &fixed)?;
+    }
+
+    if bless {
+        std::fs::write(&fixed_file, &fixed)?;
     }
 
     let expected_fixed = fs::read_to_string(&fixed_file)
-        .context(format!("could read fixed file for {}", file.display()))?
+        .context(format!("could read fixed file {}", fixed_file.display()))?
         .replace('\r', "");
     ensure!(
         fixed.trim() == expected_fixed.trim(),
-        "file {} doesn't look fixed:\n{}",
-        file.display(),
+        "file {} doesn't match expected fix:\n{}",
+        fixed_file.display(),
         diff(fixed.trim(), expected_fixed.trim())
     );
 
@@ -229,12 +253,12 @@ fn get_fixture_files(p: &str) -> Result<Vec<PathBuf>, Error> {
         .filter(|p| p.is_file())
         .filter(|p| {
             let x = p.to_string_lossy();
-            x.ends_with(".rs") && !x.ends_with(".fixed.rs") && !x.ends_with(".recorded.rs")
+            x.ends_with(".rs") && !x.contains(".fixed.") && !x.ends_with(".recorded.rs")
         })
         .collect())
 }
 
-fn assert_fixtures(dir: &str, mode: &str) {
+fn assert_fixtures(dir: &str, replace_mode: ReplaceMode) {
     let files = get_fixture_files(dir)
         .context(format!("couldn't load dir `{}`", dir))
         .unwrap();
@@ -254,7 +278,7 @@ fn assert_fixtures(dir: &str, mode: &str) {
             info!("skipped: {file:?}");
             continue;
         }
-        if let Err(err) = test_rustfix_with_file(file, mode) {
+        if let Err(err) = test_rustfix_with_file(file, replace_mode) {
             println!("failed: {}", file.display());
             warn!("{:?}", err);
             failures += 1;
@@ -275,5 +299,6 @@ fn assert_fixtures(dir: &str, mode: &str) {
 #[test]
 fn everything() {
     tracing_subscriber::fmt::init();
-    assert_fixtures("./tests/everything", fixmode::EVERYTHING);
+    assert_fixtures("./tests/everything", ReplaceMode::Combined);
+    assert_fixtures("./tests/separate", ReplaceMode::Separate);
 }

crates/rustfix/tests/separate/multiple.fixed.0.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let mut a = 0;
+    a += 1;
+    a += 2;
+
+    // Should be `_unused` in `.fixed.0.rs` but left as `unused` in `.fixed.1.rs`
+    let _unused = a;
+}

crates/rustfix/tests/separate/multiple.fixed.1.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let mut a = 0;
+    a = a + a + 1;
+    a = a + a + 2;
+
+    // Should be `_unused` in `.fixed.0.rs` but left as `unused` in `.fixed.1.rs`
+    let unused = a;
+}