From a19593b383f208106d019cbca3546cb0748eb377 Mon Sep 17 00:00:00 2001
From: Keith Hall <keith-hall@users.noreply.github.com>
Date: Fri, 20 Mar 2026 23:53:30 +0200
Subject: [PATCH] improvements from PR review

1. Added `Deserialize` derive and `#[serde(try_from = "RawMatcher")]` to the `Matcher` struct. With `try_from`, serde generates a `Deserialize` impl that first deserializes into `RawMatcher`, then calls `TryFrom<RawMatcher> for Matcher`. It never attempts to deserialize `Matcher`'s fields directly, so `Case` and `MatcherSegment` don't need `Deserialize` impls.
2. Replaced the manual `impl<'de> serde::Deserialize<'de> for Matcher` with a standard `impl TryFrom<RawMatcher> for Matcher`. The logic is identical - the conversion is fallible because `Matcher::from_str` returns `Result<_, anyhow::Error>`, so `try_from` (not `from`) is the correct choice, avoiding any panics.

The net effect: same behavior, same error handling, but using the idiomatic serde pattern instead of a manual deserializer impl. The `RawMatcher` intermediate type and its `#[serde(untagged)]` derive remain unchanged.
---
 build/syntax_mapping.rs | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/build/syntax_mapping.rs b/build/syntax_mapping.rs
index bc4601fc..c7133be9 100644
--- a/build/syntax_mapping.rs
+++ b/build/syntax_mapping.rs
@@ -66,7 +66,8 @@ impl ToTokens for Case {
     }
 }
 
-#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash, Deserialize)]
+#[serde(try_from = "RawMatcher")]
 /// A single matcher.
 ///
 /// Codegen converts this into a `Lazy<Option<GlobMatcher>>`.
@@ -161,16 +162,17 @@ enum RawMatcher {
     },
 }
 
-impl<'de> serde::Deserialize<'de> for Matcher {
-    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
-        let raw = RawMatcher::deserialize(deserializer)?;
+impl TryFrom<RawMatcher> for Matcher {
+    type Error = anyhow::Error;
+
+    fn try_from(raw: RawMatcher) -> Result<Self, Self::Error> {
         match raw {
-            RawMatcher::Simple(s) => Matcher::from_str(&s).map_err(serde::de::Error::custom),
+            RawMatcher::Simple(s) => Matcher::from_str(&s),
             RawMatcher::Full {
                 glob,
                 case_sensitive,
             } => {
-                let mut matcher = Matcher::from_str(&glob).map_err(serde::de::Error::custom)?;
+                let mut matcher = Matcher::from_str(&glob)?;
                 matcher.case = if case_sensitive {
                     Case::Sensitive
                 } else {