Replace most panics in the core library with results

src/static_data/libraries/nature_library.rs

@@ -1,5 +1,7 @@
 use crate::static_data::Nature;
 use crate::{Random, StringKey, ValueIdentifiable, ValueIdentifier};
+use anyhow::bail;
+use anyhow_ext::{ensure, Result};
 use indexmap::IndexMap;
 use std::fmt::Debug;
 use std::sync::Arc;
@@ -11,9 +13,9 @@ pub trait NatureLibrary: Debug + ValueIdentifiable {
     /// Gets a nature by name.
     fn get_nature(&self, key: &StringKey) -> Option<Arc<dyn Nature>>;
     /// Gets a random nature.
-    fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature>;
+    fn get_random_nature(&self, rand: &mut Random) -> Result<Arc<dyn Nature>>;
     /// Finds a nature name by nature.
-    fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey;
+    fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> Result<StringKey>;
 }
 
 /// A library of all natures that can be used, stored by their names.
@@ -46,21 +48,28 @@ impl NatureLibrary for NatureLibraryImpl {
         self.map.get(key).cloned()
     }
 
-    fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature> {
+    fn get_random_nature(&self, rand: &mut Random) -> Result<Arc<dyn Nature>> {
+        ensure!(!self.map.is_empty(), "No natures were loaded into the library.");
         let i = rand.get_between(0, self.map.len() as i32);
-        return self.map.get_index(i as usize).unwrap().1.clone();
+        Ok(self
+            .map
+            .get_index(i as usize)
+            // this should never happen, but we'll check anyway.
+            .ok_or(anyhow_ext::anyhow!("Failed to get a random nature from the library."))?
+            .1
+            .clone())
     }
 
     /// Finds a nature name by nature.
-    fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey {
+    fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> Result<StringKey> {
         for kv in &self.map {
             // As natures can't be copied, and should always be the same reference as the value
             // in the map, we just compare by reference.
             if kv.1.value_identifier() == nature.value_identifier() {
-                return kv.0.clone();
+                return Ok(kv.0.clone());
             }
         }
-        panic!("No name was found for the given nature. This should never happen.");
+        bail!("No name was found for the given nature. The nature may not be in the library.");
     }
 }
 
@@ -71,6 +80,9 @@ impl ValueIdentifiable for NatureLibraryImpl {
 }
 
 #[cfg(test)]
+#[allow(clippy::indexing_slicing)]
+#[allow(clippy::unwrap_used)]
+#[allow(clippy::expect_used)]
 pub mod tests {
     use super::*;
     use crate::static_data::statistics::Statistic;
@@ -93,8 +105,8 @@ pub mod tests {
         impl NatureLibrary for NatureLibrary {
             fn load_nature(&mut self, name: StringKey, nature: Arc<dyn Nature>);
             fn get_nature(&self, key: &StringKey) -> Option<Arc<dyn Nature>>;
-            fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey;
-            fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature>;
+            fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> Result<StringKey>;
+            fn get_random_nature(&self, rand: &mut Random) -> Result<Arc<dyn Nature>>;
         }
         impl ValueIdentifiable for NatureLibrary {
             fn value_identifier(&self) -> ValueIdentifier{
@@ -134,10 +146,10 @@ pub mod tests {
         );
 
         let n1 = lib.get_nature(&"foo".into()).expect("Nature was not found");
-        let name = lib.get_nature_name(&n1);
+        let name = lib.get_nature_name(&n1).unwrap();
         assert_eq!(name, "foo".into());
         let n2 = lib.get_nature(&"bar".into()).expect("Nature was not found");
-        let name2 = lib.get_nature_name(&n2);
+        let name2 = lib.get_nature_name(&n2).unwrap();
         assert_eq!(name2, "bar".into());
     }
 
@@ -148,7 +160,7 @@ pub mod tests {
             "foo".into(),
             NatureImpl::new(Statistic::HP, Statistic::Attack, 1.1, 0.9),
         );
-        let n1 = lib.get_random_nature(&mut Random::new(0));
+        let n1 = lib.get_random_nature(&mut Random::new(0)).unwrap();
         assert_eq!(n1.increased_stat(), Statistic::HP);
         assert_eq!(n1.decreased_stat(), Statistic::Attack);
         assert_eq!(n1.get_stat_modifier(n1.increased_stat()), 1.1);