[lint] fix nullable args to non-nullable function

The signature of GradleDetector.checkDslPropertyAssignment changed,
and then changed back (see the linked bug); in the rollback, this case
in LintIdeGradleVisitor was missed.  Fix the handling of the
qualifierExpression for top-level reference expressions with one
argument, and introduce additional defensiveness for the name
of the potential property (though I have never encountered a case
where that is null, the annotations imply it could be).

Bug: 170026127
Test: added
Change-Id: Ic82cd46e869d7230c67536a2e406535b7eb8f6b7

1 files changed, 9 insertions, 6 deletions

diff --git a/lint/src/com/android/tools/idea/lint/common/LintIdeGradleVisitor.java b/lint/src/com/android/tools/idea/lint/common/LintIdeGradleVisitor.java
index f317eeecdb4..fe7ab85c6a8 100644
--- a/lint/src/com/android/tools/idea/lint/common/LintIdeGradleVisitor.java
+++ b/lint/src/com/android/tools/idea/lint/common/LintIdeGradleVisitor.java
@@ -219,15 +219,18 @@ public class LintIdeGradleVisitor extends GradleVisitor {
               if (invokedExpression instanceof GrReferenceExpression) {
                 GrReferenceExpression referenceExpression = (GrReferenceExpression) invokedExpression;
                 GrExpression qualifierExpression = referenceExpression.getQualifierExpression();
+                String qualifierName = "";
                 if (qualifierExpression != null) {
-                  parentName = qualifierExpression.getText();
+                  qualifierName = qualifierExpression.getText();
                 }
                 String name = referenceExpression.getReferenceName();
-                String value = unnamedArguments.get(0);
-                GrCommandArgumentList argumentList = applicationStatement.getArgumentList();
-                for (GradleScanner detector : detectors) {
-                  detector.checkDslPropertyAssignment(context, name, value, parentName, null,
-                                                      invokedExpression, argumentList, applicationStatement);
+                if (name != null) {
+                  String value = unnamedArguments.get(0);
+                  GrCommandArgumentList argumentList = applicationStatement.getArgumentList();
+                  for (GradleScanner detector : detectors) {
+                    detector.checkDslPropertyAssignment(context, name, value, qualifierName, null,
+                                                        invokedExpression, argumentList, applicationStatement);
+                  }
                 }
               }
             }