Bugfix/negative intspec (#29)

* Write a failing test for allowing negaive ints

* Update the IntSpec to use the same intish check as HH\Lib\Str\to_int.

* Document regression of nolonger allowing leading zeroes.

* Document the regression that ints that exceed uint64 will nolonger return 2^63-1

* Allow 007 to be cast to int(7)

* Write a failing test for a the string /0{2,}/

* The string with just zeroes previously cast to 0.

* Add big-number tests

* Declare that intspec does not convert hex

* Typo

Author: lexidor

src/TypeSpec/__Private/IntSpec.hack

@@ -12,6 +12,7 @@ namespace Facebook\TypeSpec\__Private;
 
 use type Facebook\TypeAssert\{IncorrectTypeException, TypeCoercionException};
 use type Facebook\TypeSpec\TypeSpec;
+use namespace HH\Lib\Str;
 
 final class IntSpec extends TypeSpec<int> {
   <<__Override>>
@@ -22,8 +23,25 @@ final class IntSpec extends TypeSpec<int> {
     if ($value instanceof \Stringish) {
       /* HH_FIXME[4281] Stringish is going */
       $str = (string)$value;
-      if ($str !== '' && \ctype_digit($str)) {
-        return (int)$str;
+      $int = (int)$str;
+
+      // "1234"   -(int)->   1234   -(string)->   "1234"
+      // "-1234"  -(int)->   -1234  -(string)->   "-1234"
+      //   ^^           are the same                ^^
+      if ($str === (string)$int) {
+        return $int;
+      }
+
+      // "0001234" -(trim)-> "1234" -(int)-> 1234 -(string)-> "1234"
+      //                       ^^        are the same           ^^
+      $str = Str\trim_left($str, '0');
+      if ($str === (string)$int) {
+        return $int;
+      }
+
+      // Exceptional case "000" -(trim)-> "", but we want to return 0
+      if ($str === '' && $value !== '') {
+        return 0;
       }
     }
     throw TypeCoercionException::withValue($this->getTrace(), 'int', $value);

tests/IntSpecTest.hack

@@ -12,6 +12,7 @@ namespace Facebook\TypeAssert;
 
 use namespace Facebook\TypeSpec;
 use type Facebook\TypeSpec\TypeSpec;
+use namespace HH\Lib\Math;
 
 final class IntSpecTest extends TypeSpecTest<int> {
   <<__Override>>
@@ -27,6 +28,12 @@ final class IntSpecTest extends TypeSpecTest<int> {
       tuple('0', 0),
       tuple('123', 123),
       tuple(new TestStringable('123'), 123),
+      tuple((string)Math\INT64_MAX, Math\INT64_MAX),
+      tuple('-321', -321),
+      tuple((string)Math\INT64_MIN, Math\INT64_MIN),
+      tuple(new TestStringable('-321'), -321),
+      tuple('007', 7),
+      tuple('000', 0),
     ];
   }
 
@@ -44,6 +51,11 @@ final class IntSpecTest extends TypeSpecTest<int> {
       [null],
       [false],
       [new TestStringable('1.23')],
+      ['-007'],
+      [new TestStringable('-007')],
+      ['9223372036854775808'], //Math\INT64_MAX+1
+      ['-9223372036854775809'], //Math\INT64_MIN-1
+      ['0xFF'],
     ];
   }
 }