Windows: java_binary can be an action executable

This change introduces a new output of java_binary
on Windows: %{name}.cmd, a Windows-compatible Java
launcher script. This simply calls out to bash.exe
passing the shell launcher we use on other
platforms.

This change allows java_binary to be the
executable of a Skylark action or any SpawnAction.

Fixes https://github.com/bazelbuild/bazel/issues/1925

RELNOTES[NEW]: Bazel on Windows: java_binary can now be a the executable of Skylark rule actions (ctx.action's executable argument)

--
MOS_MIGRATED_REVID=137708331

5 files changed, 96 insertions, 6 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/BUILD b/src/main/java/com/google/devtools/build/lib/BUILD
index 1d3dcc97eb..901b0d9987 100644
--- a/src/main/java/com/google/devtools/build/lib/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/BUILD
@@ -594,6 +594,7 @@ java_library(
     srcs = glob(["bazel/*.java"]),
     resources = [
         "bazel/rules/java/java_stub_template.txt",
+        "bazel/rules/java/java_stub_template_windows.txt",
         "bazel/rules/python/stub_template.txt",
     ],
     deps = [
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
index c3c85e68ad..9fe7b81d71 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaSemantics.java
@@ -33,6 +33,7 @@ import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Co
 import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Substitution;
 import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Template;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.bazel.rules.BazelConfiguration;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.packages.BuildType;
@@ -52,6 +53,7 @@ import com.google.devtools.build.lib.rules.java.JavaUtil;
 import com.google.devtools.build.lib.rules.java.Jvm;
 import com.google.devtools.build.lib.rules.java.proto.GeneratedExtensionRegistryProvider;
 import com.google.devtools.build.lib.syntax.Type;
+import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.util.ShellEscaper;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -71,6 +73,8 @@ public class BazelJavaSemantics implements JavaSemantics {
 
   private static final Template STUB_SCRIPT =
       Template.forResource(BazelJavaSemantics.class, "java_stub_template.txt");
+  private static final Template STUB_SCRIPT_WINDOWS =
+      Template.forResource(BazelJavaSemantics.class, "java_stub_template_windows.txt");
 
   private static final String JAVABUILDER_CLASS_NAME =
       "com.google.devtools.build.buildjar.BazelJavaBuilder";
@@ -155,8 +159,12 @@ public class BazelJavaSemantics implements JavaSemantics {
   }
 
   @Override
-  public void createStubAction(RuleContext ruleContext, final JavaCommon javaCommon,
-      List<String> jvmFlags, Artifact executable, String javaStartClass,
+  public Artifact createStubAction(
+      RuleContext ruleContext,
+      final JavaCommon javaCommon,
+      List<String> jvmFlags,
+      Artifact executable,
+      String javaStartClass,
       String javaExecutable) {
     Preconditions.checkState(ruleContext.getConfiguration().hasFragment(Jvm.class));
 
@@ -195,6 +203,33 @@ public class BazelJavaSemantics implements JavaSemantics {
 
     ruleContext.registerAction(new TemplateExpansionAction(
         ruleContext.getActionOwner(), executable, STUB_SCRIPT, arguments, true));
+    if (OS.getCurrent() == OS.WINDOWS) {
+      Artifact newExecutable =
+          ruleContext.getImplicitOutputArtifact(ruleContext.getTarget().getName() + ".cmd");
+      ruleContext.registerAction(
+          new TemplateExpansionAction(
+              ruleContext.getActionOwner(),
+              newExecutable,
+              STUB_SCRIPT_WINDOWS,
+              ImmutableList.of(
+                  Substitution.of(
+                      "%bash_exe_path%",
+                      ruleContext
+                          .getFragment(BazelConfiguration.class)
+                          .getShellExecutable()
+                          .getPathString()),
+                  Substitution.of(
+                      "%cygpath_exe_path%",
+                      ruleContext
+                          .getFragment(BazelConfiguration.class)
+                          .getShellExecutable()
+                          .replaceName("cygpath.exe")
+                          .getPathString())),
+              true));
+      return newExecutable;
+    } else {
+      return executable;
+    }
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/java_stub_template_windows.txt b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/java_stub_template_windows.txt
new file mode 100644
index 0000000000..d3f47434bb
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/java_stub_template_windows.txt
@@ -0,0 +1,31 @@
+@rem Copyright 2016 The Bazel Authors. All rights reserved.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem    http://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem This script was generated from java_stub_template_windows.txt.  Please
+@rem don't edit it directly.
+@rem See the header comments in the accompanying shell script (same path as that
+@rem of this file, minus the ".cmd" extension) for available command line flags.
+
+@SETLOCAL ENABLEEXTENSIONS
+
+@set bash_path=%bash_exe_path%
+@set cygpath_path=%cygpath_exe_path%
+
+@rem launcher=${$0%.cmd}
+@set launcher=%~dp0%~n0
+
+@rem sh_path=$($cygpath_path -m $launcher)
+@for /f %%i in ('%cygpath_path% -m %launcher%') do @set sh_path=%%i
+
+@call %bash_path% -c "%sh_path% %*"
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
index 01de5495da..cd0173e777 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaBinary.java
@@ -228,8 +228,19 @@ public class JavaBinary implements RuleConfiguredTargetFactory {
 
     if (createExecutable) {
       // Create a shell stub for a Java application
-      semantics.createStubAction(ruleContext, common, jvmFlags, executable, mainClass,
-          JavaCommon.getJavaBinSubstitution(ruleContext, launcher));
+      Artifact newExecutable =
+          semantics.createStubAction(
+              ruleContext,
+              common,
+              jvmFlags,
+              executable,
+              mainClass,
+              JavaCommon.getJavaBinSubstitution(ruleContext, launcher));
+      if (!newExecutable.equals(executable)) {
+        filesBuilder.add(newExecutable);
+        runfilesBuilder.addArtifact(newExecutable);
+        executable = newExecutable;
+      }
     }
 
     JavaSourceJarsProvider javaSourceJarsProvider = javaSourceJarsProviderBuilder.build();
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSemantics.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSemantics.java
index 8f3be1af11..10a59d2a6c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaSemantics.java
@@ -254,9 +254,21 @@ public interface JavaSemantics {
 
   /**
    * Creates the action that writes the Java executable stub script.
+   *
+   * <p>Returns the launcher script artifact. This may or may not be the same as {@code executable},
+   * depending on the implementation of this method. If they are different, the returned value
+   * should be used as the stub script instead of the input {@code executable}.
+   *
+   * <p>For example on Windows we use a double dispatch approach: the launcher is a batch file (and
+   * is created and returned by this method) which shells out to a shell script (the {@code
+   * executable} argument).
    */
-  void createStubAction(RuleContext ruleContext, final JavaCommon javaCommon,
-      List<String> jvmFlags, Artifact executable, String javaStartClass,
+  Artifact createStubAction(
+      RuleContext ruleContext,
+      final JavaCommon javaCommon,
+      List<String> jvmFlags,
+      Artifact executable,
+      String javaStartClass,
       String javaExecutable);
 
   /**