Add tests for if/loop condition undefined array (#211)

* Add tests for undefined arrays inside if conditions

* Add test for while loop as well

* Correct tests to allow undefined after array assign

This actually matches the current behavior for non-array variables. It's
sometimes wrong, but further determination would require runtime
checking or static analysis.

Author: sirbrillig

Tests/VariableAnalysisSniff/IfConditionTest.php

@@ -28,6 +28,8 @@ public function testIfConditionWarnings() {
       87,
       98,
       101,
+      159,
+      166,
     ];
     $this->assertEquals($expectedWarnings, $lines);
   }
@@ -56,6 +58,8 @@ public function testInlineIfConditionWarnings() {
       77,
       86,
       88,
+      130,
+      136,
     ];
     $this->assertEquals($expectedWarnings, $lines);
   }

Tests/VariableAnalysisSniff/fixtures/FunctionWithIfConditionFixture.php

@@ -145,3 +145,25 @@ function ifConditionWithPossibleUse($first) {
     echo $name;
   }
 }
+
+function ifConditionWithArrayAssignment($first) {
+  $things = [];
+  if ($first) {
+    $things[] = 'person';
+  }
+  return $things;
+}
+
+function ifConditionWithUndefinedArrayAssignment($first) {
+  if ($first) {
+    $things[] = 'person'; // undefined array variable
+  }
+  return $things;
+}
+
+function loopAndPushWithUndefinedArray($parts) {
+  while ($part = array_shift($parts)) {
+    $suggestions[] = $part; // undefined array variable
+  }
+  return $suggestions;
+}

Tests/VariableAnalysisSniff/fixtures/FunctionWithInlineIfConditionFixture.php

@@ -124,3 +124,15 @@ function ifConditionWithPossibleUse($first) {
   if ($first)
     echo $name;
 }
+
+function ifConditionWithUndefinedArrayAssignment($first) {
+  if ($first)
+    $things[] = 'person'; // undefined array variable
+  return $things;
+}
+
+function loopAndPushWithUndefinedArray($parts) {
+  while ($part = array_shift($parts))
+    $suggestions[] = $part; // undefined array variable
+  return $suggestions;
+}