Make protobuf_example publishable by having it only perform code generation behind a feature.

PiperOrigin-RevId: 703150378

Author: protobuf-github-bot

rust/release_crates/cargo_test.sh

@@ -68,7 +68,7 @@ CARGO_HOME=$CARGO_HOME cargo test --lib --bins --tests
 CARGO_HOME=$CARGO_HOME cargo publish --dry-run
 
 cd $EXAMPLE_ROOT
-CARGO_HOME=$CARGO_HOME cargo test
+CARGO_HOME=$CARGO_HOME cargo test --features run-protobuf-codegen
 # TODO: Cannot enable this dry-run yet because it checks that the versions of
 # its dependencies are published on crates.io, which they are definitely not
 # in this case.

rust/release_crates/protobuf_codegen/src/lib.rs

@@ -64,8 +64,7 @@ impl CodeGen {
         self
     }
 
-    /// Generate Rust, upb, and upb minitables. Build and link the C code.
-    pub fn compile(&self) -> Result<(), String> {
+    pub fn generate_and_compile(&self) -> Result<(), String> {
         let libupb_version = std::env::var("DEP_LIBUPB_VERSION").expect("DEP_LIBUPB_VERSION should have been set, make sure that the Protobuf crate is a dependency");
         if VERSION != libupb_version {
             panic!(
@@ -112,7 +111,11 @@ impl CodeGen {
         println!("{}", std::str::from_utf8(&output.stdout).unwrap());
         eprintln!("{}", std::str::from_utf8(&output.stderr).unwrap());
         assert!(output.status.success());
+        self.compile_only()
+    }
 
+    /// Builds and links the C code.
+    pub fn compile_only(&self) -> Result<(), String> {
         let mut cc_build = cc::Build::new();
         cc_build
             .include(

rust/release_crates/protobuf_example/Cargo-template.toml

@@ -5,6 +5,9 @@ edition = "2021"
 description = "Example use of Rust Protocol Buffers bindings"
 license = "BSD-3-Clause"
 
+[features]
+run-protobuf-codegen = []
+
 [dependencies]
 protobuf = { version = "{VERSION}", path = "../protobuf", package = "staging-protobuf" }
 

rust/release_crates/protobuf_example/build.rs

@@ -3,5 +3,9 @@ use protobuf_codegen::CodeGen;
 fn main() {
     let mut codegen = CodeGen::new();
     codegen.inputs(["foo.proto", "bar/bar.proto"]).include("proto");
-    codegen.compile().unwrap();
+    if std::env::var("CARGO_FEATURE_RUN_PROTOBUF_CODEGEN").is_ok() {
+        codegen.generate_and_compile().unwrap();
+    } else {
+        codegen.compile_only().unwrap();
+    }
 }

rust/release_crates/release.sh

@@ -64,6 +64,7 @@ CARGO_HOME=$CARGO_HOME CARGO_REGISTRY_TOKEN=$AUTH_TOKEN cargo publish
 
 # The example crate cannot be published due to it having a build.rs that
 # modifies files outside of the OUT_DIR.
-#cd $EXAMPLE_ROOT
-# CARGO_HOME=$CARGO_HOME CARGO_REGISTRY_TOKEN=$AUTH_TOKEN cargo publish
+cd $EXAMPLE_ROOT
+CARGO_HOME=$CARGO_HOME cargo build --features run-protobuf-codegen
+CARGO_HOME=$CARGO_HOME CARGO_REGISTRY_TOKEN=$AUTH_TOKEN cargo publish