Migrate rustdoc verify output files

src/tools/run-make-support/src/diff/mod.rs

@@ -51,7 +51,10 @@ impl Diff {
     /// Specify the actual output for the diff from a file.
     pub fn actual_file<P: AsRef<Path>>(&mut self, path: P) -> &mut Self {
         let path = path.as_ref();
-        let content = std::fs::read_to_string(path).expect("failed to read file");
+        let content = match std::fs::read_to_string(path) {
+            Ok(c) => c,
+            Err(e) => panic!("failed to read `{}`: {:?}", path.display(), e),
+        };
         let name = path.to_string_lossy().to_string();
 
         self.actual = Some(content);

src/tools/run-make-support/src/lib.rs

@@ -12,6 +12,8 @@ pub mod rustc;
 pub mod rustdoc;
 
 use std::env;
+use std::fs;
+use std::io;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Output};
 
@@ -201,6 +203,71 @@ pub fn set_host_rpath(cmd: &mut Command) {
     });
 }
 
+/// Copy a directory into another.
+pub fn copy_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) {
+    fn copy_dir_all_inner(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
+        let dst = dst.as_ref();
+        if !dst.is_dir() {
+            fs::create_dir_all(&dst)?;
+        }
+        for entry in fs::read_dir(src)? {
+            let entry = entry?;
+            let ty = entry.file_type()?;
+            if ty.is_dir() {
+                copy_dir_all_inner(entry.path(), dst.join(entry.file_name()))?;
+            } else {
+                fs::copy(entry.path(), dst.join(entry.file_name()))?;
+            }
+        }
+        Ok(())
+    }
+
+    if let Err(e) = copy_dir_all_inner(&src, &dst) {
+        // Trying to give more context about what exactly caused the failure
+        panic!(
+            "failed to copy `{}` to `{}`: {:?}",
+            src.as_ref().display(),
+            dst.as_ref().display(),
+            e
+        );
+    }
+}
+
+/// Check that all files in `dir1` exist and have the same content in `dir2`. Panic otherwise.
+pub fn recursive_diff(dir1: impl AsRef<Path>, dir2: impl AsRef<Path>) {
+    fn read_file(path: &Path) -> Vec<u8> {
+        match fs::read(path) {
+            Ok(c) => c,
+            Err(e) => panic!("Failed to read `{}`: {:?}", path.display(), e),
+        }
+    }
+
+    let dir2 = dir2.as_ref();
+    for entry in fs::read_dir(dir1).unwrap() {
+        let entry = entry.unwrap();
+        let entry_name = entry.file_name();
+        let path = entry.path();
+
+        if path.is_dir() {
+            recursive_diff(&path, &dir2.join(entry_name));
+        } else {
+            let path2 = dir2.join(entry_name);
+            let file1 = read_file(&path);
+            let file2 = read_file(&path2);
+
+            // We don't use `assert_eq!` because they are `Vec<u8>`, so not great for display.
+            // Why not using String? Because there might be minified files or even potentially
+            // binary ones, so that would display useless output.
+            assert!(
+                file1 == file2,
+                "`{}` and `{}` have different content",
+                path.display(),
+                path2.display(),
+            );
+        }
+    }
+}
+
 /// Implement common helpers for command wrappers. This assumes that the command wrapper is a struct
 /// containing a `cmd: Command` field and a `output` function. The provided helpers are:
 ///

src/tools/run-make-support/src/rustdoc.rs

@@ -151,6 +151,13 @@ impl Rustdoc {
         self
     }
 
+    /// Specify the output format.
+    pub fn output_format(&mut self, format: &str) -> &mut Self {
+        self.cmd.arg("--output-format");
+        self.cmd.arg(format);
+        self
+    }
+
     #[track_caller]
     pub fn run_fail_assert_exit_code(&mut self, code: i32) -> Output {
         let caller_location = std::panic::Location::caller();

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -227,7 +227,6 @@ run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/rmeta-preferred/Makefile
 run-make/rustc-macro-dep-files/Makefile
 run-make/rustdoc-io-error/Makefile
-run-make/rustdoc-verify-output-files/Makefile
 run-make/sanitizer-cdylib-link/Makefile
 run-make/sanitizer-dylib-link/Makefile
 run-make/sanitizer-staticlib-link/Makefile

tests/run-make/rustdoc-verify-output-files/rmake.rs

@@ -0,0 +1,49 @@
+use std::fs::copy;
+use std::path::{Path, PathBuf};
+
+use run_make_support::{copy_dir_all, recursive_diff, rustdoc, tmp_dir};
+
+#[derive(PartialEq)]
+enum JsonOutput {
+    Yes,
+    No,
+}
+
+fn generate_docs(out_dir: &Path, json_output: JsonOutput) {
+    let mut rustdoc = rustdoc();
+    rustdoc.input("src/lib.rs").crate_name("foobar").crate_type("lib").out_dir(&out_dir);
+    if json_output == JsonOutput::Yes {
+        rustdoc.arg("-Zunstable-options").output_format("json");
+    }
+    rustdoc.run();
+}
+
+fn main() {
+    let out_dir = tmp_dir().join("rustdoc");
+    let tmp_out_dir = tmp_dir().join("tmp-rustdoc");
+
+    // Generate HTML docs.
+    generate_docs(&out_dir, JsonOutput::No);
+
+    // Copy first output for to check if it's exactly same after second compilation.
+    copy_dir_all(&out_dir, &tmp_out_dir);
+
+    // Generate html docs once again on same output.
+    generate_docs(&out_dir, JsonOutput::No);
+
+    // Generate json doc on the same output.
+    generate_docs(&out_dir, JsonOutput::Yes);
+
+    // Check if expected json file is generated.
+    assert!(out_dir.join("foobar.json").is_file());
+
+    // Copy first json output to check if it's exactly same after second compilation.
+    copy(out_dir.join("foobar.json"), tmp_out_dir.join("foobar.json")).unwrap();
+
+    // Generate json doc on the same output.
+    generate_docs(&out_dir, JsonOutput::Yes);
+
+    // Check if all docs(including both json and html formats) are still the same after multiple
+    // compilations.
+    recursive_diff(&out_dir, &tmp_out_dir);
+}