Write to log file when using DEBUG=*

CHANGELOG.md

@@ -10,14 +10,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Upgrade: Automatically convert candidates with arbitrary values to their utilities ([#17831](https://github.com/tailwindlabs/tailwindcss/pull/17831), [#17854](https://github.com/tailwindlabs/tailwindcss/pull/17854))
+- Write to log file when using `DEBUG=*` ([#17906](https://github.com/tailwindlabs/tailwindcss/pull/17906))
 
 ### Fixed
 
 - Ensure negative arbitrary `scale` values generate negative values ([#17831](https://github.com/tailwindlabs/tailwindcss/pull/17831))
 - Fix HAML extraction with embedded Ruby ([#17846](https://github.com/tailwindlabs/tailwindcss/pull/17846))
 - Don't scan files for utilities when using `@reference` ([#17836](https://github.com/tailwindlabs/tailwindcss/pull/17836))
 - Fix incorrectly replacing `_` with ` ` in arbitrary modifier shorthand `bg-red-500/(--my_opacity)` ([#17889](https://github.com/tailwindlabs/tailwindcss/pull/17889))
-- Upgrade: Bump dependendencies in parallel and make the upgrade faster ([#17898](https://github.com/tailwindlabs/tailwindcss/pull/17898))
+- Upgrade: Bump dependencies in parallel and make the upgrade faster ([#17898](https://github.com/tailwindlabs/tailwindcss/pull/17898))
 
 ## [4.1.5] - 2025-04-30
 

crates/oxide/src/scanner/mod.rs

@@ -16,10 +16,13 @@ use fxhash::{FxHashMap, FxHashSet};
 use ignore::{gitignore::GitignoreBuilder, WalkBuilder};
 use rayon::prelude::*;
 use std::collections::{BTreeMap, BTreeSet};
+use std::fs::OpenOptions;
+use std::io::{self, Write};
 use std::path::{Path, PathBuf};
 use std::sync::{self, Arc, Mutex};
 use std::time::SystemTime;
 use tracing::event;
+use tracing_subscriber::fmt::writer::BoxMakeWriter;
 
 // @source "some/folder";               // This is auto source detection
 // @source "some/folder/**/*";          // This is auto source detection
@@ -40,13 +43,41 @@ fn init_tracing() {
         return;
     }
 
+    let file = format!("tailwindcss-{}.log", std::process::id());
+    let file = OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(&file)
+        .unwrap_or_else(|_| panic!("Failed to open {file}"));
+
+    let file = Arc::new(Mutex::new(file));
+
+    let writer: BoxMakeWriter = BoxMakeWriter::new({
+        let file = file.clone();
+        move || Box::new(MutexWriter(file.clone())) as Box<dyn Write + Send>
+    });
+
     _ = tracing_subscriber::fmt()
         .with_max_level(tracing::Level::INFO)
         .with_span_events(tracing_subscriber::fmt::format::FmtSpan::ACTIVE)
+        .with_writer(writer)
+        .with_ansi(false)
         .compact()
         .try_init();
 }
 
+struct MutexWriter(Arc<Mutex<std::fs::File>>);
+
+impl Write for MutexWriter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.0.lock().unwrap().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.0.lock().unwrap().flush()
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum ChangedContent {
     File(PathBuf, String),
@@ -394,7 +425,10 @@ impl Scanner {
 fn read_changed_content(c: ChangedContent) -> Option<Vec<u8>> {
     let (content, extension) = match c {
         ChangedContent::File(file, extension) => match std::fs::read(&file) {
-            Ok(content) => (content, extension),
+            Ok(content) => {
+                event!(tracing::Level::INFO, "Reading {:?}", file);
+                (content, extension)
+            }
             Err(e) => {
                 event!(tracing::Level::ERROR, "Failed to read file: {:?}", e);
                 return None;
@@ -706,7 +740,11 @@ fn create_walker(sources: Sources) -> Option<WalkBuilder> {
 
             match (current_time, previous_time) {
                 (Some(current), Some(prev)) if prev == current => false,
-                _ => true,
+                _ => {
+                    event!(tracing::Level::INFO, "Discovering {:?}", path);
+
+                    true
+                }
             }
         }
     });