Track client environment in Skyframe

...to determine which actions have to be recomputed based on changes
to the client environment. Note that this change does it the simple way
and reconsideres all actions on a changed client environment, while still
only reexecuting those, where the part that was inherited from the environment
actually did change.

--
Change-Id: Ie1116d094642165e5e959447a6fcf49d19b37d6e
Reviewed-on: https://bazel-review.googlesource.com/#/c/5431
MOS_MIGRATED_REVID=133010705

1 files changed, 40 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java b/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
index 1ace4adb91..bb6fb831a6 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/CommandEnvironment.java
@@ -57,10 +57,11 @@ import com.google.devtools.common.options.OptionsProvider;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.TreeMap;
+import java.util.TreeSet;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -77,7 +78,8 @@ public final class CommandEnvironment {
   private final Reporter reporter;
   private final EventBus eventBus;
   private final BlazeModule.ModuleEnvironment blazeModuleEnvironment;
-  private final Map<String, String> clientEnv = new HashMap<>();
+  private final Map<String, String> clientEnv = new TreeMap<>();
+  private final Set<String> visibleClientEnv = new TreeSet<>();
   private final TimestampGranularityMonitor timestampGranularityMonitor;
 
   private String[] crashData;
@@ -163,6 +165,21 @@ public final class CommandEnvironment {
     return Collections.unmodifiableMap(clientEnv);
   }
 
+  /**
+   * Return an ordered version of the client environment restricted to those variables
+   * whitelisted by the command-line options to be inheritable by actions.
+   */
+  private Map<String, String> getCommandlineWhitelistedClientEnv() {
+    Map<String, String> visibleEnv = new TreeMap<>();
+    for (String var : visibleClientEnv) {
+      String value = clientEnv.get(var);
+      if (value != null) {
+        visibleEnv.put(var, value);
+      }
+    }
+    return Collections.unmodifiableMap(visibleEnv);
+  }
+
   @VisibleForTesting
   void updateClientEnv(List<Map.Entry<String, String>> clientEnvList, boolean ignoreClientEnv) {
     Preconditions.checkState(clientEnv.isEmpty());
@@ -407,8 +424,16 @@ public final class CommandEnvironment {
     if (!skyframeExecutor.hasIncrementalState()) {
       skyframeExecutor.resetEvaluator();
     }
-    skyframeExecutor.sync(reporter, packageCacheOptions, getOutputBase(),
-        getWorkingDirectory(), defaultsPackageContents, getCommandId(),
+    skyframeExecutor.sync(
+        reporter,
+        packageCacheOptions,
+        getOutputBase(),
+        getWorkingDirectory(),
+        defaultsPackageContents,
+        getCommandId(),
+        // TODO(bazel-team): this optimization disallows rule-specified additional dependencies
+        // on the client environment!
+        getCommandlineWhitelistedClientEnv(),
         timestampGranularityMonitor);
   }
 
@@ -499,6 +524,17 @@ public final class CommandEnvironment {
         testEnv.put(entry.getKey(), entry.getValue());
       }
 
+      // Compute the set of environment variables that are whitelisted on the commandline
+      // for inheritence.
+      for (Map.Entry<String, String> entry :
+             optionsParser.getOptions(BuildConfiguration.Options.class).actionEnvironment) {
+        if (entry.getValue() == null) {
+          visibleClientEnv.add(entry.getKey());
+        } else {
+          visibleClientEnv.remove(entry.getKey());
+        }
+      }
+
       try {
         for (Map.Entry<String, String> entry : testEnv.entrySet()) {
           if (entry.getValue() == null) {