Remove error suppression in Regex HSL

Reviewed By: fredemmott

Differential Revision: D16659539

fbshipit-source-id: 0a72c07ed9321665f9d0628ec2f3be3bdd58f19a

src/private.php

@@ -102,3 +102,25 @@ public function get(): Tr {
     throw $this->exception;
   }
 }
+
+/**
+ * Many PHP builtins emit warnings to stderr when they fail. This
+ * class allows us to squash warnings for a time without using PHP's
+ * `@` annotation.
+ */
+final class PHPWarningSuppressor implements \IDisposable {
+
+  private int $warningLevel;
+
+  public function __construct() {
+    /* HH_IGNORE_ERROR[2049] __PHPStdLib */
+    /* HH_IGNORE_ERROR[4107] __PHPStdLib */
+    $this->warningLevel = \error_reporting(0);
+  }
+
+  public function __dispose(): void {
+    /* HH_IGNORE_ERROR[2049] __PHPStdLib */
+    /* HH_IGNORE_ERROR[4107] __PHPStdLib */
+    \error_reporting($this->warningLevel);
+  }
+}

src/regex/private.php

@@ -33,11 +33,12 @@ function regex_match<T as Regex\Match>(
   Regex\Pattern<T> $pattern,
   int $offset = 0,
 ): ?(T, int) {
+  using new PHPWarningSuppressor();
   $offset = validate_offset($offset, Str\length($haystack));
   $match = darray[];
   /* HH_IGNORE_ERROR[2049] __PHPStdLib */
   /* HH_IGNORE_ERROR[4107] __PHPStdLib */
-  $status = @\preg_match(
+  $status = \preg_match(
     /* HH_IGNORE_ERROR[4110] */ $pattern,
     $haystack,
     /* HH_FIXME[3080] References are being removed from Hack */

src/regex/regex.php

@@ -102,9 +102,10 @@ function replace<T as Match>(
   $haystack1 = Str\slice($haystack, 0, $offset);
   $haystack2 = Str\slice($haystack, $offset);
 
+  using new _Private\PHPWarningSuppressor();
   /* HH_IGNORE_ERROR[2049] __PHPStdLib */
   /* HH_IGNORE_ERROR[4107] __PHPStdLib */
-  $haystack3 = @\preg_replace($pattern, $replacement, $haystack2);
+  $haystack3 = \preg_replace($pattern, $replacement, $haystack2);
   if ($haystack3 === null) {
     throw new Exception($pattern);
   }