From a3a3927c721e7bbd5d58442564003b334d2b0ffb Mon Sep 17 00:00:00 2001
From: Chapman Flack <chap@anastigmatix.net>
Date: Fri, 14 Jun 2024 19:16:54 -0400
Subject: [PATCH] Hush recent javac annotation-processor warnings

Recent versions of javac warn that annotation processing might not
happen in the future unless --processor, --processor-path,
--processor-module-path, or some -proc option is explicitly given.
Nothing was going to break, because the POMs where annotation
processing needs to happen already set --processor-module-path.
But that doesn't silence the warning. Only an explicit -proc:full
or -processor org.postgresql.pljava.annotation.processing.DDRProcessor
accomplishes that. Because -proc:full is unrecognized before Java 21,
but the longwinded -processor spec works in all supported versions,
the longwinded form is used here (even though it seems a complete waste
of the elegance of the original processor discovery scheme).

Warnings were also appearing in a couple of compilations where no
annotation processing was needed or expected. When compiling the
PGXS plugin, the warning appeared because an unexpected and unneeded
processor org.eclipse.sisu.space.SisuIndexAPT6 was being found in one
of the 70 classpath elements glommed together to build a Maven plugin.
When building the pljava-packaging classes, the POM names the other
PL/Java modules as dependencies (because they must exist before they
can be packaged), with the side effect of adding them to the classpath,
so PL/Java's processor is found, though not needed for the packaging
code. In both of those modules, add -proc:none (which is recognized in
all supported versions; only -proc:full was newer).

The longwinded approach of naming an exact processor class might be
hygienically preferable to the broad -proc:full, as less prone to
surprises when another processor like SisuIndexAPT6 happens to exist
on the classpath. (Assuming the other processor is nonmalicious, and
is looking for annotations the code being compiled doesn't use, the
processor wouldn't be expected to do anything, yielding surprise
of the mildest possible kind. Still, anyone very averse to surprise
might prefer to name the expected processor explicitly.)
---
 pljava-examples/pom.xml  | 5 +++++
 pljava-packaging/pom.xml | 3 +++
 pljava-pgxs/pom.xml      | 8 ++++++++
 pljava/pom.xml           | 5 +++++
 4 files changed, 21 insertions(+)

diff --git a/pljava-examples/pom.xml b/pljava-examples/pom.xml
index 497d6a4d9..6c9cd8562 100644
--- a/pljava-examples/pom.xml
+++ b/pljava-examples/pom.xml
@@ -58,6 +58,11 @@
 						<arg>--processor-module-path</arg>
 						<arg>${basedir}/../pljava-api/target/pljava-api-${project.version}.jar</arg>
 					</compilerArgs>
+					<annotationProcessors>
+						<annotationProcessor>
+							org.postgresql.pljava.annotation.processing.DDRProcessor
+						</annotationProcessor>
+					</annotationProcessors>
 				</configuration>
 			</plugin>
 			<plugin>
diff --git a/pljava-packaging/pom.xml b/pljava-packaging/pom.xml
index ee19ad959..66cb2c594 100644
--- a/pljava-packaging/pom.xml
+++ b/pljava-packaging/pom.xml
@@ -172,6 +172,9 @@ function execute()
 						<goals>
 							<goal>compile</goal>
 						</goals>
+						<configuration>
+							<proc>none</proc>
+						</configuration>
 					</execution>
 				</executions>
 			</plugin>
diff --git a/pljava-pgxs/pom.xml b/pljava-pgxs/pom.xml
index c53ff1e22..414816cc7 100644
--- a/pljava-pgxs/pom.xml
+++ b/pljava-pgxs/pom.xml
@@ -56,6 +56,14 @@
 
 	<build>
 		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<configuration>
+					<proc>none</proc>
+				</configuration>
+			</plugin>
+
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-plugin-plugin</artifactId>
diff --git a/pljava/pom.xml b/pljava/pom.xml
index 52491f1c1..85c5e0b07 100644
--- a/pljava/pom.xml
+++ b/pljava/pom.xml
@@ -30,6 +30,11 @@
 						<arg>--processor-module-path</arg>
 						<arg>${basedir}/../pljava-api/target/pljava-api-${project.version}.jar</arg>
 					</compilerArgs>
+					<annotationProcessors>
+						<annotationProcessor>
+							org.postgresql.pljava.annotation.processing.DDRProcessor
+						</annotationProcessor>
+					</annotationProcessors>
 				</configuration>
 			</plugin>
 		</plugins>