2 files changed, 41 insertions, 46 deletions

diff --git a/cli/src/watch.rs b/cli/src/watch.rs
index e70b6910..2ad73f85 100644
--- a/cli/src/watch.rs
+++ b/cli/src/watch.rs
@@ -1,12 +1,13 @@
 use std::collections::HashSet;
 use std::io::{self, IsTerminal, Write};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use codespan_reporting::term::{self, termcolor};
-use notify::{RecommendedWatcher, Watcher};
+use notify::{RecommendedWatcher, RecursiveMode, Watcher};
 use same_file::is_same_file;
 use termcolor::WriteColor;
 use typst::diag::StrResult;
+use typst::eval::eco_format;
 
 use crate::args::CompileCommand;
 use crate::color_stream;
@@ -27,7 +28,7 @@ pub fn watch(mut command: CompileCommand) -> StrResult<()> {
         .map_err(|_| "failed to setup file watching")?;
 
     // Watch all the files that are used by the input file and its dependencies.
-    world.watch(&mut watcher, HashSet::new())?;
+    watch_dependencies(&mut world, &mut watcher, HashSet::new())?;
 
     // Handle events.
     let timeout = std::time::Duration::from_millis(100);
@@ -45,18 +46,47 @@ pub fn watch(mut command: CompileCommand) -> StrResult<()> {
 
         if recompile {
             // Retrieve the dependencies of the last compilation.
-            let dependencies = world.dependencies();
+            let previous: HashSet<PathBuf> =
+                world.dependencies().map(ToOwned::to_owned).collect();
 
             // Recompile.
             compile_once(&mut world, &mut command, true)?;
             comemo::evict(10);
 
             // Adjust the watching.
-            world.watch(&mut watcher, dependencies)?;
+            watch_dependencies(&mut world, &mut watcher, previous)?;
         }
     }
 }
 
+/// Adjust the file watching. Watches all new dependencies and unwatches
+/// all `previous` dependencies that are not relevant anymore.
+#[tracing::instrument(skip_all)]
+fn watch_dependencies(
+    world: &mut SystemWorld,
+    watcher: &mut dyn Watcher,
+    mut previous: HashSet<PathBuf>,
+) -> StrResult<()> {
+    // Watch new paths that weren't watched yet.
+    for path in world.dependencies() {
+        let watched = previous.remove(path);
+        if path.exists() && !watched {
+            tracing::info!("Watching {}", path.display());
+            watcher
+                .watch(path, RecursiveMode::NonRecursive)
+                .map_err(|_| eco_format!("failed to watch {path:?}"))?;
+        }
+    }
+
+    // Unwatch old paths that don't need to be watched anymore.
+    for path in previous {
+        tracing::info!("Unwatching {}", path.display());
+        watcher.unwatch(&path).ok();
+    }
+
+    Ok(())
+}
+
 /// Whether a watch event is relevant for compilation.
 fn is_event_relevant(event: &notify::Event, output: &Path) -> bool {
     // Never recompile because the output file changed.
diff --git a/cli/src/world.rs b/cli/src/world.rs
index f3dfaa42..f09a3f6c 100644
--- a/cli/src/world.rs
+++ b/cli/src/world.rs
@@ -1,12 +1,11 @@
 use std::cell::{OnceCell, RefCell, RefMut};
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 use std::fs;
 use std::hash::Hash;
 use std::path::{Path, PathBuf};
 
 use chrono::Datelike;
 use comemo::Prehashed;
-use notify::{RecursiveMode, Watcher};
 use same_file::Handle;
 use siphasher::sip128::{Hasher128, SipHasher13};
 use typst::diag::{FileError, FileResult, StrResult};
@@ -45,6 +44,7 @@ pub struct SystemWorld {
 }
 
 impl SystemWorld {
+    /// Create a new system world.
     pub fn new(command: &CompileCommand) -> StrResult<Self> {
         let mut searcher = FontSearcher::new();
         searcher.search(&command.font_paths);
@@ -89,47 +89,12 @@ impl SystemWorld {
         self.main
     }
 
-    /// Adjust the file watching. Watches all new dependencies and unwatches
-    /// all `previous` dependencies that are not relevant anymore.
-    #[tracing::instrument(skip_all)]
-    pub fn watch(
-        &self,
-        watcher: &mut dyn Watcher,
-        mut previous: HashSet<PathBuf>,
-    ) -> StrResult<()> {
-        // Watch new paths that weren't watched yet.
-        for slot in self.paths.borrow().values() {
-            let path = &slot.system_path;
-            let watched = previous.remove(path);
-            if path.exists() && !watched {
-                tracing::info!("Watching {}", path.display());
-                watcher
-                    .watch(path, RecursiveMode::NonRecursive)
-                    .map_err(|_| eco_format!("failed to watch {path:?}"))?;
-            }
-        }
-
-        // Unwatch old paths that don't need to be watched anymore.
-        for path in previous {
-            tracing::info!("Unwatching {}", path.display());
-            watcher.unwatch(&path).ok();
-        }
-
-        Ok(())
+    /// Return all paths the last compilation depended on.
+    pub fn dependencies(&mut self) -> impl Iterator<Item = &Path> {
+        self.paths.get_mut().values().map(|slot| slot.system_path.as_path())
     }
 
-    /// Collect all paths the last compilation depended on.
-    #[tracing::instrument(skip_all)]
-    pub fn dependencies(&self) -> HashSet<PathBuf> {
-        self.paths
-            .borrow()
-            .values()
-            .map(|slot| slot.system_path.clone())
-            .collect()
-    }
-
-    /// Reset th compilation state in preparation of a new compilation.
-    #[tracing::instrument(skip_all)]
+    /// Reset the compilation state in preparation of a new compilation.
     pub fn reset(&mut self) {
         self.hashes.borrow_mut().clear();
         self.paths.borrow_mut().clear();