Add a linter rule for invalid octals

Summary: PHP doesn't handle octals very well. Basically, it seems that any numeric scalar matching `/^0\d+$/` will be treated as an octal, whereas this should be `/^0[0-7]+$/`. As a result, `08` and `09` are both treated as `0` (because they are invalid octals. This diff adds a linter rule to detect this abnormality.

Test Plan: Added unit tests.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D14604

src/__phutil_library_map__.php

@@ -190,6 +190,8 @@ phutil_register_library_map(array(
     'ArcanistInvalidDefaultParameterXHPASTLinterRuleTestCase' => 'lint/linter/xhpast/rules/__tests__/ArcanistInvalidDefaultParameterXHPASTLinterRuleTestCase.php',
     'ArcanistInvalidModifiersXHPASTLinterRule' => 'lint/linter/xhpast/rules/ArcanistInvalidModifiersXHPASTLinterRule.php',
     'ArcanistInvalidModifiersXHPASTLinterRuleTestCase' => 'lint/linter/xhpast/rules/__tests__/ArcanistInvalidModifiersXHPASTLinterRuleTestCase.php',
+    'ArcanistInvalidOctalNumericScalarXHPASTLinterRule' => 'lint/linter/xhpast/rules/ArcanistInvalidOctalNumericScalarXHPASTLinterRule.php',
+    'ArcanistInvalidOctalNumericScalarXHPASTLinterRuleTestCase' => 'lint/linter/xhpast/rules/__tests__/ArcanistInvalidOctalNumericScalarXHPASTLinterRuleTestCase.php',
     'ArcanistJSHintLinter' => 'lint/linter/ArcanistJSHintLinter.php',
     'ArcanistJSHintLinterTestCase' => 'lint/linter/__tests__/ArcanistJSHintLinterTestCase.php',
     'ArcanistJSONLintLinter' => 'lint/linter/ArcanistJSONLintLinter.php',
@@ -590,6 +592,8 @@ phutil_register_library_map(array(
     'ArcanistInvalidDefaultParameterXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistInvalidModifiersXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
     'ArcanistInvalidModifiersXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
+    'ArcanistInvalidOctalNumericScalarXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
+    'ArcanistInvalidOctalNumericScalarXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistJSHintLinter' => 'ArcanistExternalLinter',
     'ArcanistJSHintLinterTestCase' => 'ArcanistExternalLinterTestCase',
     'ArcanistJSONLintLinter' => 'ArcanistExternalLinter',

src/lint/linter/xhpast/rules/ArcanistInvalidOctalNumericScalarXHPASTLinterRule.php

@@ -0,0 +1,44 @@
+<?php
+
+final class ArcanistInvalidOctalNumericScalarXHPASTLinterRule
+  extends ArcanistXHPASTLinterRule {
+
+  const ID = 125;
+
+  public function getLintName() {
+    return pht('Invalid Octal Numeric Scalar');
+  }
+
+  public function process(XHPASTNode $root) {
+    $octals = $this->getOctalNumericScalars($root);
+
+    foreach ($octals as $octal) {
+      if (!preg_match('/^0[0-7]*$/', $octal->getConcreteString())) {
+        $this->raiseLintAtNode(
+          $octal,
+          pht(
+            'Invalid octal numeric scalar. `%s` is not a '.
+            'valid octal and will be interpreted as `%d`.',
+            $octal->getConcreteString(),
+            intval($octal->getConcreteString(), 8)));
+      }
+    }
+  }
+
+  private function getOctalNumericScalars(XHPASTNode $root) {
+    $numeric_scalars = $root->selectDescendantsOfType('n_NUMERIC_SCALAR');
+    $octal_numeric_scalars = array();
+
+    foreach ($numeric_scalars as $numeric_scalar) {
+      $number = $numeric_scalar->getConcreteString();
+
+      if (preg_match('/^0\d+$/', $number)) {
+        $octal_numeric_scalars[] = $numeric_scalar;
+      }
+    }
+
+    return $octal_numeric_scalars;
+
+  }
+
+}

src/lint/linter/xhpast/rules/__tests__/ArcanistInvalidOctalNumericScalarXHPASTLinterRuleTestCase.php

@@ -0,0 +1,11 @@
+<?php
+
+final class ArcanistInvalidOctalNumericScalarXHPASTLinterRuleTestCase
+  extends ArcanistXHPASTLinterRuleTestCase {
+
+  public function testLinter() {
+    $this->executeTestsInDirectory(
+      dirname(__FILE__).'/invalid-octal-numeric-scalar/');
+  }
+
+}

src/lint/linter/xhpast/rules/__tests__/invalid-octal-numeric-scalar/binary.lint-test

@@ -0,0 +1,3 @@
+<?php
+0b01;
+~~~~~~~~

src/lint/linter/xhpast/rules/__tests__/invalid-octal-numeric-scalar/decimal.lint-test

@@ -0,0 +1,5 @@
+<?php
+0;
+123;
+0.9;
+~~~~~~~~~~

src/lint/linter/xhpast/rules/__tests__/invalid-octal-numeric-scalar/hexadecimal.lint-test

@@ -0,0 +1,4 @@
+<?php
+0xFf;
+0XFf;
+~~~~~~~~

src/lint/linter/xhpast/rules/__tests__/invalid-octal-numeric-scalar/octal.lint-test

@@ -0,0 +1,7 @@
+<?php
+01234567;
+08;
+-08;
+~~~~~~~~
+error:3:1
+error:4:2