Add salesforce/reactive-grpc/protoc-gen-reactor-grpc

[altaiezior]

https://github.com/salesforce/reactive-grpc/tree/master/reactor/reactor-grpc - Reactor-gRPC is a set of gRPC bindings for reactive programming with Reactor

Check List

• Read CONTRIBUTING.md
  • ⚠️ Avoid force push
  • ⚠️ Use argd s command when adding new packages
• Install and execute the package and confirm if the package works well

[suzuki-shunsuke]

Review by Claude Opus 4.7 (1M context)

Summary

This PR cannot be merged as-is. The downloaded artifact is a protoc
plugin, not a standalone CLI, and the package is named in a way that
prevents protoc from discovering it.

What the binary actually is

The .exe published to Maven Central
(com.salesforce.servicelibs:reactor-grpc:<ver>:<os>-<arch>) is not a
self-contained native CLI. It is built with
Salesforce Canteen: a small Go
bootstrap with a JAR appended at the end. Running it requires a JRE on
PATH or in JAVA_HOME.

Evidence (strings against the downloaded artifact):

github.com/salesforce/canteen
/Users/rmichela/dev/grpc-java-contrib/canteen/canteen-bootstrap/src/main/go/main.go
Java not found in PATH and JAVA_HOME not set: %v
Java not found in JAVA_HOME: %v
JAVA_HOME is not a directory: %v

file output:

reactor-grpc-1.2.4-osx-aarch_64.exe: Mach-O 64-bit executable arm64

The upstream usage (see the pom.xml snippet in the project README) wires
it into protobuf-maven-plugin as a protocPlugin with mainClass: com.salesforce.reactorgrpc.ReactorGrpcGenerator. It is not designed to be
invoked by an end user with --help. When invoked by protoc, it reads a
CodeGeneratorRequest from stdin and writes a CodeGeneratorResponse to
stdout.

The error reported during testing,

$ reactor-grpc --help
Error: Unable to access jarfile reactor-grpc

is the canteen bootstrap passing os.Args[0] (the symlink basename
reactor-grpc) to java -jar; Java then looks for a file literally named
reactor-grpc in the CWD and fails. This is not something the registry can
fix — the binary is simply not meant to be run by hand.

Required changes

1. Rename the package to protoc-gen-reactor-grpc

The package name determines the installed command name. To be useful as a
protoc plugin (protoc --reactor-grpc_out=...), the binary must be
discoverable as protoc-gen-reactor-grpc on $PATH.

There is direct precedent for this in the registry:
grpc/grpc-java/protoc-gen-grpc-java
follows the same pattern (Maven Central + Canteen + Java required) and is
named after the protoc-plugin convention.

Concretely:

• Move pkgs/salesforce/reactive-grpc/reactor-grpc/ →
  pkgs/salesforce/reactive-grpc/protoc-gen-reactor-grpc/.
• Update name: in registry.yaml, pkg.yaml, and scaffold.yaml to
  salesforce/reactive-grpc/protoc-gen-reactor-grpc.
• The Maven Central URL path stays the same
  (com/salesforce/servicelibs/reactor-grpc/...), only the aqua package
  name changes.

2. Verify with protoc, not by direct invocation

Per CONTRIBUTING.md, please paste the verification
command and its output into the PR body. A direct run of the binary is not
a valid test. A real test looks like:

argd t protoc-gen-reactor-grpc
java -version  # Java must be installed

cat > /tmp/s.proto <<'EOF'
syntax = "proto3";
service S { rpc R (M) returns (M); }
message M {}
EOF

protoc \
  --plugin=protoc-gen-reactor-grpc="$(aqua which protoc-gen-reactor-grpc)" \
  --reactor-grpc_out=/tmp /tmp/s.proto
ls /tmp/*.java

3. Drop the trailing . in description

Per the agent guide:

description: Reactor-gRPC is a set of gRPC bindings for reactive programming with Reactor

4. Confirm windows_arm_emulation: true is justified

This flag only does something if a windows-x86_64.exe artifact exists on
Maven Central for this version. Please verify; otherwise drop it.

Things that look good

• format: raw with no files: block is correct for a single binary.
• replacements (darwin: osx, amd64: x86_64, arm64: aarch_64) match
  the os-maven-plugin classifier convention used by Maven Central.
• The .sha1 checksum URL resolves on Maven Central.

Optional follow-ups

• The same Salesforce repo also publishes rx-java, rx3-java, and the
  Spring Reactor variants under the same Canteen+Maven pattern. They are
  out of scope for this PR but would be valid follow-ups, each named
  protoc-gen-<flavor>.

[suzuki-shunsuke]

I'll push some commits.

[suzuki-shunsuke]

• Renamed the package to salesforce/reactive-grpc/protoc-gen-reactor-grpc.
• Renamed the command to protoc-gen-reactor-grpc

I've confirmed protoc-gen-reactor-grpc works fine.

⚠️ java and protoc are required.

cat > /tmp/s.proto <<'EOF'
syntax = "proto3";
service S { rpc R (M) returns (M); }
message M {}
EOF

protoc \
  --plugin=protoc-gen-reactor-grpc="$(aqua which protoc-gen-reactor-grpc)" \
  -I /tmp --reactor-grpc_out=/tmp /tmp/s.proto
ls /tmp/*.java

/tmp/ReactorSGrpc.java

[altaiezior]

Thanks @suzuki-shunsuke for making the changes and approving it :)