Fix turbine command lines with empty javacopts

See #4422

PiperOrigin-RevId: 181497117

1 files changed, 5 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaHeaderCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaHeaderCompileAction.java
index 933d69b36d..6cffa7b35a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaHeaderCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaHeaderCompileAction.java
@@ -549,9 +549,11 @@ public class JavaHeaderCompileAction extends SpawnAction {
         result.addExecPaths("--source_jars", ImmutableList.copyOf(sourceJars));
       }
 
-      result.addAll("--javacopts", javacOpts);
-      // terminate --javacopts with `--` to support javac flags that start with `--`
-      result.add("--");
+      if (!javacOpts.isEmpty()) {
+        result.addAll("--javacopts", javacOpts);
+        // terminate --javacopts with `--` to support javac flags that start with `--`
+        result.add("--");
+      }
 
       if (ruleKind != null) {
         result.add("--rule_kind", ruleKind);