diff -Naur a/src/main/java/com/google/devtools/build/lib/shell/JavaSubprocessFactory.java b/src/main/java/com/google/devtools/build/lib/shell/JavaSubprocessFactory.java
--- a/src/main/java/com/google/devtools/build/lib/shell/JavaSubprocessFactory.java	2019-06-12 20:39:37.538708196 -0700
+++ b/src/main/java/com/google/devtools/build/lib/shell/JavaSubprocessFactory.java	2019-06-12 20:44:18.863429602 -0700
@@ -146,7 +146,6 @@
     ProcessBuilder builder = new ProcessBuilder();
     builder.command(params.getArgv());
     if (params.getEnv() != null) {
-      builder.environment().clear();
       builder.environment().putAll(params.getEnv());
     }