conf::data_types: minor style and error msg fixups

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

meli/src/conf/data_types/dotaddressable.rs

@@ -43,6 +43,7 @@ impl DotAddressable for bool {}
 impl DotAddressable for String {}
 impl DotAddressable for char {}
 impl DotAddressable for data_types::IndexStyle {}
+impl DotAddressable for data_types::SearchBackend {}
 impl DotAddressable for u64 {}
 impl DotAddressable for TagHash {}
 impl DotAddressable for crate::terminal::Color {}
@@ -54,7 +55,6 @@ impl DotAddressable for melib::LogLevel {}
 impl DotAddressable for PathBuf {}
 impl DotAddressable for ToggleFlag {}
 impl DotAddressable for ActionFlag {}
-impl DotAddressable for data_types::SearchBackend {}
 impl DotAddressable for melib::SpecialUsageMailbox {}
 impl<T: DotAddressable> DotAddressable for Option<T> {}
 impl<T: DotAddressable> DotAddressable for Vec<T> {}

meli/src/conf/data_types/mod.rs

@@ -41,11 +41,16 @@ impl<'de> Deserialize<'de> for IndexStyle {
     {
         let s = <String>::deserialize(deserializer)?;
         match s.as_str() {
-            "Plain" | "plain" => Ok(Self::Plain),
-            "Threaded" | "threaded" => Ok(Self::Threaded),
-            "Compact" | "compact" => Ok(Self::Compact),
-            "Conversations" | "conversations" => Ok(Self::Conversations),
-            _ => Err(de::Error::custom("invalid `index_style` value")),
+            plain if plain.eq_ignore_ascii_case("plain") => Ok(Self::Plain),
+            threaded if threaded.eq_ignore_ascii_case("threaded") => Ok(Self::Threaded),
+            compact if compact.eq_ignore_ascii_case("compact") => Ok(Self::Compact),
+            conversations if conversations.eq_ignore_ascii_case("conversations") => {
+                Ok(Self::Conversations)
+            }
+            _ => Err(de::Error::custom(
+                "invalid `index_style` value, expected one of: \"plain\", \"threaded\", \
+                 \"compact\" or \"conversations\".",
+            )),
         }
     }
 }
@@ -94,7 +99,12 @@ impl<'de> Deserialize<'de> for SearchBackend {
                 Ok(Self::None)
             }
             auto if auto.eq_ignore_ascii_case("auto") => Ok(Self::Auto),
-            _ => Err(de::Error::custom("invalid `search_backend` value")),
+            _ => Err(de::Error::custom(if cfg!(feature = "sqlite3") {
+                "invalid `search_backend` value, expected one of: \"sqlite3\", \"sqlite\", \
+                 \"none\" or \"auto\"."
+            } else {
+                "invalid `search_backend` value, expected one of: \"none\" or \"auto\"."
+            })),
         }
     }
 }