From 4097ed1e1c403ea099025626f1119284f39a668e Mon Sep 17 00:00:00 2001
From: Colin Alworth <colin@vertispan.com>
Date: Wed, 13 Sep 2023 10:52:33 -0500
Subject: [PATCH] Use --release 8 to ensure bytecode runs on all support JVMs
 (#9851)

The ant task `java` is able to take source, target, and release flags
and only set the appropriate ones given the version of javac being
invoked.

The doctool package always sets this to 11, since the new doclet/taglet
APIs require Java 9+.

Fixes #9850
---
 build_tools/doctool/build.xml | 6 +++++-
 common.ant.xml                | 8 +++-----
 doc/build.xml                 | 4 ++--
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/build_tools/doctool/build.xml b/build_tools/doctool/build.xml
index e6524f1496..c4870197b6 100644
--- a/build_tools/doctool/build.xml
+++ b/build_tools/doctool/build.xml
@@ -4,7 +4,11 @@
   <import file="${gwt.root}/common.ant.xml" />
 
   <target name="compile" description="Compiles this project">
-    <gwt.javac />
+    <!--
+    As guarded below in the build target, doctool can't be built on
+    Java 8. In theory release could be set to 9, but 9 and 10 are EOL.
+    -->
+    <gwt.javac release="11" />
   </target>
 
   <target name="build" depends="compile" description="Packages this project into a jar" unless="${isJava8}">
diff --git a/common.ant.xml b/common.ant.xml
index 7b3604ba60..36a56b4882 100755
--- a/common.ant.xml
+++ b/common.ant.xml
@@ -62,8 +62,7 @@
   <property name="javac.debug" value="true"/>
   <property name="javac.debuglevel" value="lines,vars,source"/>
   <property name="javac.encoding" value="utf-8"/>
-  <property name="javac.source" value="8"/>
-  <property name="javac.target" value="8"/>
+  <property name="javac.release" value="8"/>
   <property name="javac.nowarn" value="true"/>
 
   <!-- javac and errorprone instructions from https://errorprone.info/docs/installation#ant -->
@@ -158,8 +157,7 @@
   <macrodef name="gwt.javac">
     <attribute name="srcdir" default="src" />
     <attribute name="destdir" default="${javac.out}" />
-    <attribute name="source" default="${javac.source}" />
-    <attribute name="target" default="${javac.target}" />
+    <attribute name="release" default="${javac.release}" />
     <attribute name="excludes" default="" />
     <attribute name="processorpath" default="" />
     <attribute name="errorprone.args" default="" />
@@ -172,7 +170,7 @@
       </path>
       <mkdir dir="@{destdir}"/>
       <javac srcdir="@{srcdir}" sourcepath="@{srcdir}" destdir="@{destdir}" debug="${javac.debug}"
-             debuglevel="${javac.debuglevel}" source="@{source}" target="@{target}"
+             debuglevel="${javac.debuglevel}" source="@{release}" target="@{release}" release="@{release}"
              nowarn="${javac.nowarn}" encoding="${javac.encoding}" includeantruntime="false"
              fork="true" compiler="modern" excludes="@{excludes}">
         <compilerarg value="-J-Xbootclasspath/p:${errorprone.javac.jar}" if:true="${isJava8}"/>
diff --git a/doc/build.xml b/doc/build.xml
index 5f41768b2f..10050f29e3 100644
--- a/doc/build.xml
+++ b/doc/build.xml
@@ -78,7 +78,7 @@
     <property file="${gwt.root}/build/out/packages.properties" />
     <javadoc classpathref="DOC_PATH" failonerror="true" maxmemory="1g"
              destdir="${project.build}/javadoc"
-             source="${javac.source}"
+             source="${javac.release}"
              encoding="UTF-8"
              access="package"
              packagenames="${USER_PKGS}"
@@ -125,7 +125,7 @@
                  sourcepath="${gwt.root}/user/super/com/google/gwt/emul:${gwt.root}/dev/core/super/com/google/gwt/dev/jjs/intrinsic"
                  encoding="UTF-8"
                  access="public"
-                 source="${javac.source}"
+                 source="${javac.release}"
                  packagenames="${JAVA_PKGS}"
                  docletpath="${project.build}/../build_tools/doctool/bin"
                  doclet="com.google.doctool.custom.JavaEmulSummaryDoclet">