Do not expand flag_groups guarded by expand_if_true/false if variable is missing

--
PiperOrigin-RevId: 143443361
MOS_MIGRATED_REVID=143443361

2 files changed, 20 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
index 4e763cb538..3681be965b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeatures.java
@@ -431,13 +431,13 @@ public class CcToolchainFeatures implements Serializable {
         }
       }
       if (expandIfTrue != null
-          && variables.isAvailable(expandIfTrue)
-          && !variables.getVariable(expandIfTrue).isTruthy()) {
+          && (!variables.isAvailable(expandIfTrue)
+              || !variables.getVariable(expandIfTrue).isTruthy())) {
         return false;
       }
       if (expandIfFalse != null
-          && variables.isAvailable(expandIfFalse)
-          && variables.getVariable(expandIfFalse).isTruthy()) {
+          && (!variables.isAvailable(expandIfFalse)
+              || variables.getVariable(expandIfFalse).isTruthy())) {
         return false;
       }
       if (expandIfEqual != null
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeaturesTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeaturesTest.java
index 949aa4297b..2d5d4887d3 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeaturesTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainFeaturesTest.java
@@ -526,6 +526,22 @@ public class CcToolchainFeaturesTest {
   }
 
   @Test
+  public void testExpandIfTrueDoesntExpandIfMissing() throws Exception {
+    assertThat(
+        getCommandLineForFlagGroups(
+            "flag_group {"
+                + "  expand_if_true: 'missing'"
+                + "  flag: '-A%{missing}'"
+                + "}"
+                + "flag_group {"
+                + "  expand_if_false: 'missing'"
+                + "  flag: '-B%{missing}'"
+                + "}",
+            createVariables()))
+        .isEmpty();
+  }
+
+  @Test
   public void testExpandIfTrueExpandsIfOne() throws Exception {
     assertThat(
             getCommandLineForFlagGroups(