pkgs/lf-make-map: Improve error message

1 files changed, 18 insertions, 13 deletions

diff --git a/pkgs/by-name/lf/lf-make-map/src/mapping/map_key.rs b/pkgs/by-name/lf/lf-make-map/src/mapping/map_key.rs
index d90eb963..6d88d5af 100644
--- a/pkgs/by-name/lf/lf-make-map/src/mapping/map_key.rs
+++ b/pkgs/by-name/lf/lf-make-map/src/mapping/map_key.rs
@@ -48,8 +48,8 @@ impl PartialOrd for MapKey {
 }
 
 impl MapKey {
-    pub fn new_from_part_path(part_path: &str, resolution: usize) -> Vec<Self> {
-        let key = Self::part_path_to_key(part_path, resolution);
+    pub fn new_from_part_path(part_path: &str, resolution: usize, full_path: &str) -> Vec<Self> {
+        let key = Self::path_part_to_key(part_path, resolution, Some(full_path));
 
         key.chars()
             .map(|ch| Self {
@@ -63,7 +63,7 @@ impl MapKey {
     pub fn new_ones_from_path(path: &str, number_of_chars: usize) -> Vec<Self> {
         let key: Vec<MapKey> = path
             .split('/')
-            .flat_map(|part| Self::new_from_part_path(part, number_of_chars))
+            .flat_map(|part| Self::new_from_part_path(part, number_of_chars, path))
             .collect();
 
         debug!(
@@ -80,10 +80,10 @@ impl MapKey {
         // debug!("Incrementing: '{}' ('{}')", &self, &self.part_path);
 
         let added_chars = if new_resolution < self.part_path.len() {
-            MapKey::part_path_to_key(&self.part_path, new_resolution)
+            MapKey::path_part_to_key(&self.part_path, new_resolution, None)
         } else {
             let mut generated_chars =
-                MapKey::part_path_to_key(&self.part_path, self.part_path.len());
+                MapKey::path_part_to_key(&self.part_path, self.part_path.len(), None);
 
             generated_chars.extend(
                 (0..(new_resolution - self.part_path.len()))
@@ -112,16 +112,21 @@ impl MapKey {
         values.iter().map(|value| value.key).collect()
     }
 
-    fn part_path_to_key(part: &str, number_of_chars: usize) -> String {
-        fn make(pat: char, part: &str, number_of_chars: usize) -> String {
+    fn path_part_to_key(part: &str, number_of_chars: usize, full_path: Option<&str>) -> String {
+        fn make(pat: char, part: &str, number_of_chars: usize, full_path: Option<&str>) -> String {
             let mut acc = String::new();
 
-            if !part.split(pat).all(|part| !part.is_empty()) {
+            if part.split(pat).all(|split| split.is_empty()) {
                 panic!(
                     "\
-Can't turn this path '{}' to a mapping.
-This should not happen, please report the bug!",
-                    part
+Failed to split path part `{part}`, with pattern `{pat}`, because all resulting split parts are empty. {}
+This should not happen, please report this bug!", {
+                        if let Some(full_path) = full_path {
+                            format!("(Full path was: `{full_path}`)")
+                        } else {
+                            String::new()
+                        }
+                    }
                 )
             }
 
@@ -148,9 +153,9 @@ This should not happen, please report the bug!",
         }
 
         let value = if part.contains('_') && !part.starts_with('_') && !part.ends_with('_') {
-            make('_', part, number_of_chars)
+            make('_', part, number_of_chars, full_path)
         } else if part.contains('-') && !part.starts_with('-') && !part.ends_with('-') {
-            make('-', part, number_of_chars)
+            make('-', part, number_of_chars, full_path)
         } else if part.starts_with('.') {
             // HACK: Special case for directories like ~/.config ~/.local and so on.
             // We just drop the starting '.' and it's easier to type. <2026-06-02>