Make dev serve actually detect all updates

Author: Jarcho

clippy_dev/src/serve.rs

@@ -1,7 +1,11 @@
+use crate::utils::{ErrAction, expect_action};
+use core::fmt::Display;
+use core::mem;
 use std::path::Path;
 use std::process::Command;
 use std::time::{Duration, SystemTime};
-use std::{env, thread};
+use std::{env, fs, thread};
+use walkdir::WalkDir;
 
 #[cfg(windows)]
 const PYTHON: &str = "python";
@@ -18,56 +22,85 @@ pub fn run(port: u16, lint: Option<String>) -> ! {
         Some(lint) => format!("http://localhost:{port}/#{lint}"),
     });
 
+    let mut last_update = mtime("util/gh-pages/index.html");
     loop {
-        let index_time = mtime("util/gh-pages/index.html");
-        let times = [
-            "clippy_lints/src",
-            "util/gh-pages/index_template.html",
-            "tests/compile-test.rs",
-        ]
-        .map(mtime);
-
-        if times.iter().any(|&time| index_time < time) {
-            Command::new(env::var("CARGO").unwrap_or_else(|_| "cargo".into()))
-                .arg("collect-metadata")
-                .spawn()
-                .unwrap()
-                .wait()
-                .unwrap();
+        if is_metadata_outdated(mem::replace(&mut last_update, SystemTime::now())) {
+            // Ignore the command result; we'll fall back to displaying the old metadata.
+            let _ = expect_action(
+                Command::new(env::var("CARGO").unwrap_or_else(|_| "cargo".into()))
+                    .arg("collect-metadata")
+                    .status(),
+                ErrAction::Run,
+                "cargo collect-metadata",
+            );
+            last_update = SystemTime::now();
         }
+
+        // Only start the web server the first time around.
         if let Some(url) = url.take() {
             thread::spawn(move || {
-                let mut child = Command::new(PYTHON)
-                    .arg("-m")
-                    .arg("http.server")
-                    .arg(port.to_string())
-                    .current_dir("util/gh-pages")
-                    .spawn()
-                    .unwrap();
+                let mut child = expect_action(
+                    Command::new(PYTHON)
+                        .args(["-m", "http.server", port.to_string().as_str()])
+                        .current_dir("util/gh-pages")
+                        .spawn(),
+                    ErrAction::Run,
+                    "python -m http.server",
+                );
                 // Give some time for python to start
                 thread::sleep(Duration::from_millis(500));
                 // Launch browser after first export.py has completed and http.server is up
                 let _result = opener::open(url);
-                child.wait().unwrap();
+                expect_action(child.wait(), ErrAction::Run, "python -m http.server");
             });
         }
+
+        // Delay to avoid updating the metadata too aggressively.
         thread::sleep(Duration::from_millis(1000));
     }
 }
 
-fn mtime(path: impl AsRef<Path>) -> SystemTime {
-    let path = path.as_ref();
-    if path.is_dir() {
-        path.read_dir()
-            .into_iter()
-            .flatten()
-            .flatten()
-            .map(|entry| mtime(entry.path()))
-            .max()
-            .unwrap_or(SystemTime::UNIX_EPOCH)
-    } else {
-        path.metadata()
-            .and_then(|metadata| metadata.modified())
-            .unwrap_or(SystemTime::UNIX_EPOCH)
+fn log_err_and_continue<T>(res: Result<T, impl Display>, path: &Path) -> Option<T> {
+    match res {
+        Ok(x) => Some(x),
+        Err(ref e) => {
+            eprintln!("error reading `{}`: {e}", path.display());
+            None
+        },
     }
 }
+
+fn mtime(path: &str) -> SystemTime {
+    log_err_and_continue(fs::metadata(path), path.as_ref())
+        .and_then(|metadata| log_err_and_continue(metadata.modified(), path.as_ref()))
+        .unwrap_or(SystemTime::UNIX_EPOCH)
+}
+
+fn is_metadata_outdated(time: SystemTime) -> bool {
+    // Ignore all IO errors here. We don't want to stop them from hosting the server.
+    if time < mtime("util/gh-pages/index_template.html") || time < mtime("tests/compile-test.rs") {
+        return true;
+    }
+    let Some(dir) = log_err_and_continue(fs::read_dir("."), ".".as_ref()) else {
+        return false;
+    };
+    dir.map_while(|e| log_err_and_continue(e, ".".as_ref())).any(|e| {
+        let name = e.file_name();
+        let name_bytes = name.as_encoded_bytes();
+        if (name_bytes.starts_with(b"clippy_lints") && name_bytes != b"clippy_lints_internal")
+            || name_bytes == b"clippy_config"
+        {
+            WalkDir::new(&name)
+                .into_iter()
+                .map_while(|e| log_err_and_continue(e, name.as_ref()))
+                .filter(|e| e.file_type().is_file())
+                .filter_map(|e| {
+                    log_err_and_continue(e.metadata(), e.path())
+                        .and_then(|m| log_err_and_continue(m.modified(), e.path()))
+                })
+                .any(|ftime| time < ftime)
+        } else {
+            false
+        }
+    })
+}