Add thiserror

Cargo.lock

@@ -245,6 +245,7 @@ dependencies = [
  "serde",
  "serde_yaml",
  "test-case",
+ "thiserror",
  "wasm-bindgen",
  "wasm-bindgen-test",
  "wee_alloc",
@@ -383,6 +384,26 @@ dependencies = [
  "test-case-core",
 ]
 
+[[package]]
+name = "thiserror"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f63587ca0f12b72a0600bcba1d40081f830876000bb46dd2337a3051618f4fc8"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.22"

Cargo.toml

@@ -22,6 +22,7 @@ path = "examples/merge-file.rs"
 
 [dependencies]
 serde = { version = "1.0.219", optional = true, features = ["derive"] }
+thiserror = "2.0.17"
 
 wasm-bindgen = { version = "0.2.99", optional = true }