Omit source code info from well known types descriptors

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Monomorphised some code in `DescriptorPool::add_*` methods to reduce binary size. Thanks to [@sjrs] for [#40] and [#41].
+- Source code info is now omitted from the built-in descriptors for well-known types. This reduces the binary size by around 100KB.
 
 ## [0.11.3] - 2023-04-11
 

prost-reflect/Cargo.toml

@@ -46,8 +46,10 @@ once_cell = "1.13.0"
 proptest = "1.0.0"
 prost-build = "0.11.0"
 prost-reflect-build = { path = "../prost-reflect-build" }
+protox = "0.3.1"
 serde_json = "1.0.82"
 serde_yaml = "0.9.16"
+similar-asserts = { version = "1.4.2", features = ["serde"] }
 
 [package.metadata.release]
 tag-name = "{{version}}"

prost-reflect/src/reflect/wkt.rs

@@ -1,6 +1,65 @@
 use crate::{DescriptorPool, MessageDescriptor, ReflectMessage};
 
-pub(crate) const WELL_KNOWN_TYPES_BYTES: &[u8] = include_bytes!("../well_known_types.bin");
+pub(crate) const WELL_KNOWN_TYPES_BYTES: &[u8] = include_bytes!(concat!(
+    env!("CARGO_MANIFEST_DIR"),
+    "/src/well_known_types.bin"
+));
+
+#[test]
+
+fn generate_well_known_types_bin() {
+    use std::fs;
+
+    use prost::Message;
+    use prost_types::FileDescriptorSet;
+    use protox::{file::GoogleFileResolver, Compiler};
+
+    // protox can output a FileDescriptorSet directly, but by going through bytes, this should still work
+    // when upgrading to a newer prost-types version.
+    let expected_bytes = Compiler::with_file_resolver(GoogleFileResolver::new())
+        .include_source_info(false)
+        .open_files([
+            "google/protobuf/any.proto",
+            "google/protobuf/api.proto",
+            "google/protobuf/descriptor.proto",
+            "google/protobuf/duration.proto",
+            "google/protobuf/empty.proto",
+            "google/protobuf/field_mask.proto",
+            "google/protobuf/source_context.proto",
+            "google/protobuf/struct.proto",
+            "google/protobuf/timestamp.proto",
+            "google/protobuf/type.proto",
+            "google/protobuf/wrappers.proto",
+            "google/protobuf/compiler/plugin.proto",
+        ])
+        .unwrap()
+        .encode_file_descriptor_set();
+
+    let actual = FileDescriptorSet::decode(WELL_KNOWN_TYPES_BYTES).unwrap();
+    let expected = FileDescriptorSet::decode(expected_bytes.as_ref()).unwrap();
+
+    if actual != expected {
+        fs::write(
+            concat!(
+                env!("CARGO_MANIFEST_DIR"),
+                "/src/well_known_types.expected.bin"
+            ),
+            expected_bytes,
+        )
+        .unwrap();
+
+        let actual_str = format!("{:#?}", actual);
+        let expected_str = format!("{:#?}", expected);
+
+        let diff =
+            similar_asserts::SimpleDiff::from_str(&actual_str, &expected_str, "actual", "expected");
+
+        panic!("Found differences in 'well_known_types.bin'.
+            If this is expected, replace 'well_known_types.bin' with 'well_known_types.actual.bin' to update it
+            \
+            differences: {}", diff);
+    }
+}
 
 macro_rules! impl_reflect_message {
     ($($ty:ty => $name:literal;)*) => {