Don't panic when UTF-8 data is invalid

2 files changed, 28 insertions, 5 deletions

diff --git a/examples/10-transient-0/output/rust/src/gen/transient_0.rs b/examples/10-transient-0/output/rust/src/gen/transient_0.rs
index 753dd23..e57324a 100644
--- a/examples/10-transient-0/output/rust/src/gen/transient_0.rs
+++ b/examples/10-transient-0/output/rust/src/gen/transient_0.rs
@@ -66,5 +66,5 @@ pub fn decode_string(reader: &mut impl std::io::Read) -> ::std::io::Result::<::s
         reader.read_exact(&mut bytes)?;
         bytes
     };
-    std::io::Result::Ok((::std::string::String::from_utf8(bytes)).unwrap())
+    std::io::Result::Ok((::std::string::String::from_utf8(bytes)).map_err(|error| ::std::io::Error::new(::std::io::ErrorKind::InvalidData, error))?)
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
index b53345e..4a37e4a 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/rusttransient0/RustTransient0Generator.java
@@ -259,12 +259,35 @@ public class RustTransient0Generator implements Generator {
                         generateReaderReadExact(RustPath.of(len))
                     )
                 ),
-                Optional.of(unwrap(
+                Optional.of(
+                    new RustTryPropagationExpression(mapErr(
+                        new RustCallExpression(
+                            RustPath.global("std", "string", "String", "from_utf8"),
+                            List.of(RustPath.of(bytes))
+                        )
+                    ))
+                )
+            )
+        );
+    }
+
+    private RustExpression mapErr(RustExpression result) {
+        var error = RustIdentifier.of("error");
+
+        return methodCall(
+            result,
+            RustIdentifier.of("map_err"),
+            List.of(
+                new RustClosureExpression(
+                    List.of(new RustIdentifierPattern(error)),
                     new RustCallExpression(
-                        RustPath.global("std", "string", "String", "from_utf8"),
-                        List.of(RustPath.of(bytes))
+                        RustPath.global("std", "io", "Error", "new"),
+                        List.of(
+                            RustPath.global("std", "io", "ErrorKind", "InvalidData"),
+                            RustPath.of(error)
+                        )
                     )
-                ))
+                )
             )
         );
     }