Fix error handling for target pattern expansion

... in register_toolchains and register_execution_platforms.

Fixes #5000.

Change-Id: Iac06b3cb79746ea720de8835b7bd1abb19149526

Closes #5001.

PiperOrigin-RevId: 192615586

1 files changed, 9 insertions, 5 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java b/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java
index e2317890e7..40d6701c33 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ToolchainUtil.java
@@ -397,23 +397,27 @@ public class ToolchainUtil {
     }
 
     // Then, resolve the patterns.
-    ImmutableList.Builder<Label> labels = new ImmutableList.Builder<>();
     Map<SkyKey, ValueOrException<TargetParsingException>> resolvedPatterns =
         env.getValuesOrThrow(patternKeys, TargetParsingException.class);
-    if (env.valuesMissing()) {
-      return null;
-    }
+    boolean valuesMissing = env.valuesMissing();
+    ImmutableList.Builder<Label> labels = valuesMissing ? null : new ImmutableList.Builder<>();
 
     for (TargetPatternValue.TargetPatternKey pattern : patternKeys) {
       TargetPatternValue value;
       try {
         value = (TargetPatternValue) resolvedPatterns.get(pattern).get();
-        labels.addAll(value.getTargets().getTargets());
+        if (!valuesMissing && value != null) {
+          labels.addAll(value.getTargets().getTargets());
+        }
       } catch (TargetParsingException e) {
         throw new InvalidTargetPatternException(pattern.getPattern(), e);
       }
     }
 
+    if (valuesMissing) {
+      return null;
+    }
+
     return labels.build();
   }