From 0b9e43334551861dbdd75732785d0cb5f3431568 Mon Sep 17 00:00:00 2001
From: Nikolaus Waxweiler <nikolaus.waxweiler@daltonmaag.com>
Date: Mon, 11 Mar 2024 12:15:24 +0000
Subject: [PATCH 1/3] Always retain the first (default) layer

---
 src/layer.rs | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/layer.rs b/src/layer.rs
index a63d54ff..82ea87e5 100644
--- a/src/layer.rs
+++ b/src/layer.rs
@@ -237,7 +237,15 @@ impl LayerContents {
     where
         F: FnMut(&Layer) -> bool,
     {
-        self.layers.retain(|layer| layer.name == DEFAULT_LAYER_NAME || predicate(layer))
+        // Always keep the default layer, which is always the first.
+        let mut is_first = true;
+        self.layers.retain(|layer| {
+            if is_first {
+                is_first = false;
+                return true;
+            }
+            predicate(layer)
+        });
     }
 
     /// Removes any layers that contain no glyphs
@@ -904,12 +912,13 @@ mod tests {
             ],
             ..Default::default()
         };
+        layers.rename_layer("public.default", "foreground", false).unwrap();
 
         layers.retain(|l| l.name().starts_with("fizz"));
 
         assert_eq!(layers.len(), 3, "wrong number of layers deleted");
         let names = layers.iter().map(|l| l.name().as_str()).collect::<Vec<_>>();
-        assert_eq!(names.as_slice(), &[DEFAULT_LAYER_NAME, "fizz", "fizzbuzz"]);
+        assert_eq!(names.as_slice(), &["foreground", "fizz", "fizzbuzz"]);
     }
 
     #[test]

From 38cd34974b3ca4d8419294a644d0e9d89ed9dfee Mon Sep 17 00:00:00 2001
From: Nikolaus Waxweiler <nikolaus.waxweiler@daltonmaag.com>
Date: Mon, 11 Mar 2024 14:08:04 +0000
Subject: [PATCH 2/3] Test for default layer path

---
 src/layer.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/layer.rs b/src/layer.rs
index 82ea87e5..2d31a289 100644
--- a/src/layer.rs
+++ b/src/layer.rs
@@ -237,11 +237,8 @@ impl LayerContents {
     where
         F: FnMut(&Layer) -> bool,
     {
-        // Always keep the default layer, which is always the first.
-        let mut is_first = true;
         self.layers.retain(|layer| {
-            if is_first {
-                is_first = false;
+            if layer.is_default() {
                 return true;
             }
             predicate(layer)
@@ -460,6 +457,14 @@ impl Layer {
         self.glyphs.is_empty()
     }
 
+    /// Returns `true` if this layer is the default layer.
+    ///
+    /// The default layer can have any name, but always uses the "glyphs"
+    /// directory.
+    pub fn is_default(&self) -> bool {
+        self.path == Path::new(DEFAULT_GLYPHS_DIRNAME)
+    }
+
     /// Returns the name of the layer.
     ///
     /// This can only be mutated through the [`LayerContents`].

From e5495490561313aeb2ebd41dbfb171932f17d0ff Mon Sep 17 00:00:00 2001
From: Nikolaus Waxweiler <nikolaus.waxweiler@daltonmaag.com>
Date: Mon, 11 Mar 2024 14:35:17 +0000
Subject: [PATCH 3/3] Shorten closure

---
 src/layer.rs | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/src/layer.rs b/src/layer.rs
index 2d31a289..ea9a3464 100644
--- a/src/layer.rs
+++ b/src/layer.rs
@@ -237,12 +237,7 @@ impl LayerContents {
     where
         F: FnMut(&Layer) -> bool,
     {
-        self.layers.retain(|layer| {
-            if layer.is_default() {
-                return true;
-            }
-            predicate(layer)
-        });
+        self.layers.retain(|layer| layer.is_default() || predicate(layer));
     }
 
     /// Removes any layers that contain no glyphs