chore: test protobuf 3.0 gen code.

.cloudbuild/library_generation/library_generation.Dockerfile

@@ -37,7 +37,7 @@ RUN cp "/root/.m2/repository/com/google/api/gapic-generator-java/${DOCKER_GAPIC_
 FROM docker.io/library/python:3.13.2-slim@sha256:6b3223eb4d93718828223966ad316909c39813dee3ee9395204940500792b740 as final
 
 ARG OWLBOT_CLI_COMMITTISH=3a68a9c0de318784b3aefadcc502a6521b3f1bc5
-ARG PROTOC_VERSION=25.8
+ARG PROTOC_VERSION=21.0
 ARG GRPC_VERSION=1.76.2
 ENV HOME=/home
 ENV OS_ARCHITECTURE="linux-x86_64"

.cloudbuild/library_generation/library_generation_airlock.Dockerfile

@@ -38,7 +38,7 @@ RUN cp "/root/.m2/repository/com/google/api/gapic-generator-java/${DOCKER_GAPIC_
 FROM us-docker.pkg.dev/artifact-foundry-prod/docker-3p-trusted/python@sha256:afc139a0a640942491ec481ad8dda10f2c5b753f5c969393b12480155fe15a63 as final
 
 ARG OWLBOT_CLI_COMMITTISH=3a68a9c0de318784b3aefadcc502a6521b3f1bc5
-ARG PROTOC_VERSION=25.8
+ARG PROTOC_VERSION=21.0
 ARG GRPC_VERSION=1.76.2
 ENV HOME=/home
 ENV OS_ARCHITECTURE="linux-x86_64"

gapic-generator-java-pom-parent/pom.xml

@@ -40,6 +40,7 @@
     <junit.version>5.11.4</junit.version>
     <mockito.version>4.11.0</mockito.version>
     <slf4j.version>2.0.16</slf4j.version>
+    <clirr.skip>true</clirr.skip>
   </properties>
 
   <developers>

java-common-protos/proto-google-common-protos/src/main/java/com/google/api/Advice.java

@@ -16,7 +16,6 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/api/config_change.proto
 
-// Protobuf Java Version: 3.25.8
 package com.google.api;
 
 /**
@@ -50,6 +49,57 @@ protected java.lang.Object newInstance(UnusedPrivateParameter unused) {
     return new Advice();
   }
 
+  @java.lang.Override
+  public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
+    return this.unknownFields;
+  }
+
+  private Advice(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    this();
+    if (extensionRegistry == null) {
+      throw new java.lang.NullPointerException();
+    }
+    com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+        com.google.protobuf.UnknownFieldSet.newBuilder();
+    try {
+      boolean done = false;
+      while (!done) {
+        int tag = input.readTag();
+        switch (tag) {
+          case 0:
+            done = true;
+            break;
+          case 18:
+            {
+              java.lang.String s = input.readStringRequireUtf8();
+
+              description_ = s;
+              break;
+            }
+          default:
+            {
+              if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
+                done = true;
+              }
+              break;
+            }
+        }
+      }
+    } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(this);
+    } catch (com.google.protobuf.UninitializedMessageException e) {
+      throw e.asInvalidProtocolBufferException().setUnfinishedMessage(this);
+    } catch (java.io.IOException e) {
+      throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
+    } finally {
+      this.unknownFields = unknownFields.build();
+      makeExtensionsImmutable();
+    }
+  }
+
   public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     return com.google.api.ConfigChangeProto.internal_static_google_api_Advice_descriptor;
   }
@@ -63,9 +113,7 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
   }
 
   public static final int DESCRIPTION_FIELD_NUMBER = 2;
-
-  @SuppressWarnings("serial")
-  private volatile java.lang.Object description_ = "";
+  private volatile java.lang.Object description_;
 
   /**
    *
@@ -134,7 +182,7 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(description_)) {
       com.google.protobuf.GeneratedMessageV3.writeString(output, 2, description_);
     }
-    getUnknownFields().writeTo(output);
+    unknownFields.writeTo(output);
   }
 
   @java.lang.Override
@@ -146,7 +194,7 @@ public int getSerializedSize() {
     if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(description_)) {
       size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, description_);
     }
-    size += getUnknownFields().getSerializedSize();
+    size += unknownFields.getSerializedSize();
     memoizedSize = size;
     return size;
   }
@@ -162,7 +210,7 @@ public boolean equals(final java.lang.Object obj) {
     com.google.api.Advice other = (com.google.api.Advice) obj;
 
     if (!getDescription().equals(other.getDescription())) return false;
-    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
+    if (!unknownFields.equals(other.unknownFields)) return false;
     return true;
   }
 
@@ -175,7 +223,7 @@ public int hashCode() {
     hash = (19 * hash) + getDescriptor().hashCode();
     hash = (37 * hash) + DESCRIPTION_FIELD_NUMBER;
     hash = (53 * hash) + getDescription().hashCode();
-    hash = (29 * hash) + getUnknownFields().hashCode();
+    hash = (29 * hash) + unknownFields.hashCode();
     memoizedHashCode = hash;
     return hash;
   }
@@ -302,17 +350,24 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
     }
 
     // Construct using com.google.api.Advice.newBuilder()
-    private Builder() {}
+    private Builder() {
+      maybeForceBuilderInitialization();
+    }
 
     private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
       super(parent);
+      maybeForceBuilderInitialization();
+    }
+
+    private void maybeForceBuilderInitialization() {
+      if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
     }
 
     @java.lang.Override
     public Builder clear() {
       super.clear();
-      bitField0_ = 0;
       description_ = "";
+
       return this;
     }
 
@@ -338,20 +393,11 @@ public com.google.api.Advice build() {
     @java.lang.Override
     public com.google.api.Advice buildPartial() {
       com.google.api.Advice result = new com.google.api.Advice(this);
-      if (bitField0_ != 0) {
-        buildPartial0(result);
-      }
+      result.description_ = description_;
       onBuilt();
       return result;
     }
 
-    private void buildPartial0(com.google.api.Advice result) {
-      int from_bitField0_ = bitField0_;
-      if (((from_bitField0_ & 0x00000001) != 0)) {
-        result.description_ = description_;
-      }
-    }
-
     @java.lang.Override
     public Builder clone() {
       return super.clone();
@@ -399,10 +445,9 @@ public Builder mergeFrom(com.google.api.Advice other) {
       if (other == com.google.api.Advice.getDefaultInstance()) return this;
       if (!other.getDescription().isEmpty()) {
         description_ = other.description_;
-        bitField0_ |= 0x00000001;
         onChanged();
       }
-      this.mergeUnknownFields(other.getUnknownFields());
+      this.mergeUnknownFields(other.unknownFields);
       onChanged();
       return this;
     }
@@ -417,42 +462,20 @@ public Builder mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
         throws java.io.IOException {
-      if (extensionRegistry == null) {
-        throw new java.lang.NullPointerException();
-      }
+      com.google.api.Advice parsedMessage = null;
       try {
-        boolean done = false;
-        while (!done) {
-          int tag = input.readTag();
-          switch (tag) {
-            case 0:
-              done = true;
-              break;
-            case 18:
-              {
-                description_ = input.readStringRequireUtf8();
-                bitField0_ |= 0x00000001;
-                break;
-              } // case 18
-            default:
-              {
-                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
-                  done = true; // was an endgroup tag
-                }
-                break;
-              } // default:
-          } // switch (tag)
-        } // while (!done)
+        parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
       } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        parsedMessage = (com.google.api.Advice) e.getUnfinishedMessage();
         throw e.unwrapIOException();
       } finally {
-        onChanged();
-      } // finally
+        if (parsedMessage != null) {
+          mergeFrom(parsedMessage);
+        }
+      }
       return this;
     }
 
-    private int bitField0_;
-
     private java.lang.Object description_ = "";
 
     /**
@@ -520,8 +543,8 @@ public Builder setDescription(java.lang.String value) {
       if (value == null) {
         throw new NullPointerException();
       }
+
       description_ = value;
-      bitField0_ |= 0x00000001;
       onChanged();
       return this;
     }
@@ -539,8 +562,8 @@ public Builder setDescription(java.lang.String value) {
      * @return This builder for chaining.
      */
     public Builder clearDescription() {
+
       description_ = getDefaultInstance().getDescription();
-      bitField0_ = (bitField0_ & ~0x00000001);
       onChanged();
       return this;
     }
@@ -563,8 +586,8 @@ public Builder setDescriptionBytes(com.google.protobuf.ByteString value) {
         throw new NullPointerException();
       }
       checkByteStringIsUtf8(value);
+
       description_ = value;
-      bitField0_ |= 0x00000001;
       onChanged();
       return this;
     }
@@ -601,18 +624,7 @@ public Advice parsePartialFrom(
             com.google.protobuf.CodedInputStream input,
             com.google.protobuf.ExtensionRegistryLite extensionRegistry)
             throws com.google.protobuf.InvalidProtocolBufferException {
-          Builder builder = newBuilder();
-          try {
-            builder.mergeFrom(input, extensionRegistry);
-          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
-            throw e.setUnfinishedMessage(builder.buildPartial());
-          } catch (com.google.protobuf.UninitializedMessageException e) {
-            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
-          } catch (java.io.IOException e) {
-            throw new com.google.protobuf.InvalidProtocolBufferException(e)
-                .setUnfinishedMessage(builder.buildPartial());
-          }
-          return builder.buildPartial();
+          return new Advice(input, extensionRegistry);
         }
       };
 

java-common-protos/proto-google-common-protos/src/main/java/com/google/api/AdviceOrBuilder.java

@@ -16,7 +16,6 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/api/config_change.proto
 
-// Protobuf Java Version: 3.25.8
 package com.google.api;
 
 public interface AdviceOrBuilder

java-common-protos/proto-google-common-protos/src/main/java/com/google/api/AnnotationsProto.java

@@ -16,7 +16,6 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/api/annotations.proto
 
-// Protobuf Java Version: 3.25.8
 package com.google.api;
 
 public final class AnnotationsProto {

java-common-protos/proto-google-common-protos/src/main/java/com/google/api/AuthProto.java

@@ -16,7 +16,6 @@
 // Generated by the protocol buffer compiler.  DO NOT EDIT!
 // source: google/api/auth.proto
 
-// Protobuf Java Version: 3.25.8
 package com.google.api;
 
 public final class AuthProto {