[hack][builder pattern] Add FP test case with not finalised builder t…

…hat doesn't have any method calls

Summary: We don't want to report builders that don't have any method calls. This may happen if builder finalisation is guarded by an external variable. This diffs adds the test case that highlights this problem.

Reviewed By: skcho

Differential Revision: D65338134

fbshipit-source-id: 4af7bbdd0d55ae9e3fbb81443d319443af2d800d

infer/tests/codetoanalyze/hack/pulse/builder.hack

@@ -101,6 +101,20 @@ class BuilderTester {
     }
   }
 
+  public static function FP_builderWithoutCallsOk(bool $flag): void {
+    $changes_made = false;
+    $b = new MyBuilder(0);
+
+    if ($flag) {
+      $b->setA(42);
+      $changes_made = true;
+    }
+
+    if ($changes_made) {
+      $b->saveX();
+    }
+  }
+
   // now check builders recognised from the .inferconfig file
   public static function testConfigBad(): void {
     $b = new NoBuilderSuffix();

infer/tests/codetoanalyze/hack/pulse/issues.exp

@@ -28,6 +28,7 @@ booleans.hack, $root.Booleans::testBoolBad, 3, TAINT_ERROR, no_bucket, ERROR, [s
 booleans.hack, $root.Booleans::testNullBad, 3, TAINT_ERROR, no_bucket, ERROR, [source of the taint here: value passed as argument `#0` to `$root.Booleans::testNullBad` with kind `Simple`,flows to this sink: value passed as argument `#0` to `$root.Level1::taintSink` with kind `Simple`], source: $root.Booleans::testNullBad, sink: $root.Level1::taintSink, tainted expression: $sc
 booleans.hack, $root.Booleans::testNotNullBad, 3, TAINT_ERROR, no_bucket, ERROR, [source of the taint here: value passed as argument `#0` to `$root.Booleans::testNotNullBad` with kind `Simple`,flows to this sink: value passed as argument `#0` to `$root.Level1::taintSink` with kind `Simple`], source: $root.Booleans::testNotNullBad, sink: $root.Level1::taintSink, tainted expression: $sc
 builder.hack, BuilderTester$static.builderUserBad, 3, PULSE_UNFINISHED_BUILDER, no_bucket, ERROR, [allocation part of the trace starts here,allocated by constructor `MyBuilder()` here,builder object becomes unreachable here]
+builder.hack, BuilderTester$static.FP_builderWithoutCallsOk, 9, PULSE_UNFINISHED_BUILDER, no_bucket, ERROR, [allocation part of the trace starts here,allocated by constructor `MyBuilder()` here,builder object becomes unreachable here]
 builder.hack, BuilderTester$static.testConfigBad, 2, PULSE_UNFINISHED_BUILDER, no_bucket, ERROR, [allocation part of the trace starts here,allocated by constructor `NoBuilderSuffix()` here,builder object becomes unreachable here]
 builder.hack, BuilderTester$static.testConfigBad2, 3, PULSE_UNFINISHED_BUILDER, no_bucket, ERROR, [allocation part of the trace starts here,allocated by constructor `NoBuilderSuffix()` here,builder object becomes unreachable here]
 builder.hack, BuilderTester2$static.testCreateBad, 3, PULSE_UNFINISHED_BUILDER, no_bucket, ERROR, [allocation part of the trace starts here,when calling `BuilderTester2$static.create` here,when calling `MyBuilder$static.__factory` here,allocated by constructor `MyBuilder()` here,builder object becomes unreachable here]