[ruby/yarp] Use templating to avoid duplicating the YARP version in many places

https://github.com/ruby/yarp/commit/9c359fd92e

lib/yarp.rb

@@ -523,6 +523,7 @@ require_relative "yarp/node"
 require_relative "yarp/ripper_compat"
 require_relative "yarp/serialize"
 require_relative "yarp/pack"
+require_relative "yarp/version"
 
 if RUBY_ENGINE == "ruby" and !ENV["YARP_FFI_BACKEND"]
   require "yarp/yarp"

lib/yarp/ffi.rb

@@ -171,8 +171,10 @@ module YARP
   # the YARP module.
   private_constant :LibRubyParser
 
-  # The version constant is set by reading the result of calling yp_version.
-  VERSION = LibRubyParser.yp_version.read_string
+  library_version = LibRubyParser.yp_version.read_string
+  if library_version != YARP::VERSION
+    raise "The YARP library version (#{library_version}) does not match the expected version (#{YARP::VERSION})"
+  end
 
   def self.dump_internal(source, source_size, filepath)
     LibRubyParser::YPBuffer.with do |buffer|

lib/yarp/version.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+module YARP
+  VERSION = "0.8.0"
+end

lib/yarp/yarp.gemspec

@@ -1,8 +1,10 @@
 # frozen_string_literal: true
 
+require_relative 'lib/yarp/version'
+
 Gem::Specification.new do |spec|
   spec.name = "yarp"
-  spec.version = "0.8.0"
+  spec.version = YARP::VERSION
   spec.authors = ["Shopify"]
   spec.email = ["ruby@shopify.com"]
 
@@ -67,6 +69,7 @@ Gem::Specification.new do |spec|
     "lib/yarp/pack.rb",
     "lib/yarp/ripper_compat.rb",
     "lib/yarp/serialize.rb",
+    "lib/yarp/version.rb",
     "src/diagnostic.c",
     "src/enc/yp_big5.c",
     "src/enc/yp_euc_jp.c",

yarp/extension.c

@@ -511,12 +511,12 @@ RUBY_FUNC_EXPORTED void
 Init_yarp(void) {
     // Make sure that the YARP library version matches the expected version.
     // Otherwise something was compiled incorrectly.
-    if (strcmp(yp_version(), EXPECTED_YARP_VERSION) != 0) {
+    if (strcmp(yp_version(), YP_VERSION) != 0) {
         rb_raise(
             rb_eRuntimeError,
             "The YARP library version (%s) does not match the expected version (%s)",
             yp_version(),
-            EXPECTED_YARP_VERSION
+            YP_VERSION
         );
     }
 
@@ -532,10 +532,6 @@ Init_yarp(void) {
     rb_cYARPParseWarning = rb_define_class_under(rb_cYARP, "ParseWarning", rb_cObject);
     rb_cYARPParseResult = rb_define_class_under(rb_cYARP, "ParseResult", rb_cObject);
 
-    // Define the version string here so that we can use the constants defined
-    // in yarp.h.
-    rb_define_const(rb_cYARP, "VERSION", rb_str_new2(EXPECTED_YARP_VERSION));
-
     rb_define_const(rb_cYARP, "BACKEND", ID2SYM(rb_intern("CExtension")));
 
     // First, the functions that have to do with lexing and parsing.

yarp/extension.h

@@ -5,8 +5,6 @@
 #include <ruby/encoding.h>
 #include "yarp.h"
 
-#define EXPECTED_YARP_VERSION "0.8.0"
-
 VALUE yp_source_new(yp_parser_t *parser);
 VALUE yp_token_new(yp_parser_t *parser, yp_token_t *token, rb_encoding *encoding, VALUE source);
 VALUE yp_ast_new(yp_parser_t *parser, yp_node_t *node, rb_encoding *encoding);

yarp/templates/include/yarp/version.h.erb

@@ -0,0 +1,9 @@
+#ifndef YARP_VERSION_H
+#define YARP_VERSION_H
+
+#define YP_VERSION_MAJOR <%= YARP_VERSION_MAJOR %>
+#define YP_VERSION_MINOR <%= YARP_VERSION_MINOR %>
+#define YP_VERSION_PATCH <%= YARP_VERSION_PATCH %>
+#define YP_VERSION "<%= YARP_VERSION %>"
+
+#endif // YARP_VERSION_H

yarp/templates/java/org/yarp/Loader.java.erb

@@ -48,10 +48,6 @@ public class Loader {
     private ConstantPool constantPool;
     private final Nodes.Source source;
 
-    private byte MAJOR_VERSION = (byte) 0;
-    private byte MINOR_VERSION = (byte) 8;
-    private byte PATCH_VERSION = (byte) 0;
-
     private Loader(byte[] serialized, Nodes.Source source) {
         this.buffer = ByteBuffer.wrap(serialized).order(ByteOrder.nativeOrder());
         this.source = source;
@@ -63,9 +59,9 @@ public class Loader {
         expect((byte) 'R');
         expect((byte) 'P');
 
-        expect(MAJOR_VERSION);
-        expect(MINOR_VERSION);
-        expect(PATCH_VERSION);
+        expect((byte) <%= YARP_VERSION_MAJOR %>);
+        expect((byte) <%= YARP_VERSION_MINOR %>);
+        expect((byte) <%= YARP_VERSION_PATCH %>);
 
         // This loads the name of the encoding. We don't actually do anything
         // with it just yet.

yarp/templates/lib/yarp/serialize.rb.erb

@@ -13,10 +13,6 @@ end
 
 module YARP
   module Serialize
-    MAJOR_VERSION = 0
-    MINOR_VERSION = 8
-    PATCH_VERSION = 0
-
     def self.load(input, serialized)
       Loader.new(Source.new(input), serialized).load
     end
@@ -64,7 +60,9 @@ module YARP
 
       def load
         raise "Invalid serialization" if io.read(4) != "YARP"
-        raise "Invalid serialization" if io.read(3).unpack("C3") != [MAJOR_VERSION, MINOR_VERSION, PATCH_VERSION]
+        if io.read(3).unpack("C3") != [<%= YARP_VERSION_MAJOR %>, <%= YARP_VERSION_MINOR %>, <%= YARP_VERSION_PATCH %>]
+          raise "Invalid serialization version"
+        end
 
         @encoding = Encoding.find(io.read(load_varint))
         @input = input.force_encoding(@encoding).freeze

yarp/templates/template.rb

@@ -4,6 +4,11 @@ require "erb"
 require "fileutils"
 require "yaml"
 
+require_relative "../lib/yarp/version"
+
+YARP_VERSION = YARP::VERSION
+YARP_VERSION_MAJOR, YARP_VERSION_MINOR, YARP_VERSION_PATCH = YARP_VERSION.split(".")
+
 COMMON_FLAGS = 1
 
 class Param
@@ -312,6 +317,7 @@ end
 TEMPLATES = [
   "ext/yarp/api_node.c",
   "include/yarp/ast.h",
+  "include/yarp/version.h",
   "java/org/yarp/Loader.java",
   "java/org/yarp/Nodes.java",
   "java/org/yarp/AbstractNodeVisitor.java",

yarp/yarp.h

@@ -13,6 +13,7 @@
 #include "yarp/util/yp_char.h"
 #include "yarp/util/yp_memchr.h"
 #include "yarp/util/yp_strpbrk.h"
+#include "yarp/version.h"
 
 #include <assert.h>
 #include <stdarg.h>