Support both shape behaviors

Author: fredemmott

src/TypeSpec/__Private/ShapeSpec.php

@@ -15,8 +15,19 @@
 use namespace HH\Lib\{C, Dict};
 
 final class ShapeSpec extends TypeSpec<shape()> {
+  const bool STRICT_SHAPES = HHVM_VERSION_ID >= 32300;
   private bool $allowUnknownFields;
 
+  private static function isOptionalField<Tany>(TypeSpec<Tany> $spec): bool {
+    if ($spec->isOptional()) {
+      return true;
+    }
+    if (self::STRICT_SHAPES) {
+      return false;
+    }
+    return $spec instanceof NullableSpec;
+  }
+
   public function __construct(
     private dict<string, TypeSpec<mixed>> $inners,
     UnknownFieldsMode $unknown_fields,
@@ -39,7 +50,7 @@ public function coerceType(mixed $value): shape() {
         continue;
       }
 
-      if ($spec->isOptional()) {
+      if (self::isOptionalField($spec)) {
         continue;
       }
 
@@ -72,7 +83,7 @@ public function assertType(mixed $value): shape() {
         continue;
       }
 
-      if ($spec->isOptional()) {
+      if (self::isOptionalField($spec)) {
         continue;
       }
 

src/TypeSpec/__Private/from_type_structure.php

@@ -114,7 +114,7 @@ function from_type_structure<T>(TypeStructure<T> $ts): TypeSpec<T> {
           ($_k, $field_ts) ==> from_type_structure($field_ts),
           ($k, $_v) ==> $k,
         ),
-        ($ts['allows_unknown_fields'] ?? false)
+        ($ts['allows_unknown_fields'] ?? !ShapeSpec::STRICT_SHAPES)
           ? UnknownFieldsMode::ALLOW
           : UnknownFieldsMode::DENY,
       );

tests/TypeStructureTest.php

@@ -198,7 +198,7 @@ public function testValidType<T>(TypeStructure<T> $ts, T $input): void {
 
   public function getExampleInvalidTypes(
   ): array<string, (mixed, mixed, vec<string>)> {
-    return [
+    $examples = [
       '"123" as int' => tuple(type_structure(C::class, 'TInt'), '123', vec[]),
       '1 as bool' => tuple(type_structure(C::class, 'TBool'), 1, vec[]),
       'int as float' => tuple(type_structure(C::class, 'TFloat'), 123, vec[]),
@@ -270,21 +270,11 @@ public function getExampleInvalidTypes(
         ),
         vec['shape[someOptionalNullable]'],
       ),
-      'shape with missing nullable field' => tuple(
-        type_structure(C::class, 'TFlatShape'),
-        shape('someString' => 'foo'),
-        vec['shape[someNullable]'],
-      ),
       'shape with incorrect field' => tuple(
         type_structure(C::class, 'TFlatShape'),
         shape('someString' => 123, 'someNullable' => null),
         vec['shape[someString]'],
       ),
-      'shape with extra fields' => tuple(
-        type_structure(C::class, 'TShapeWithOneField'),
-        shape('someString' => 'string', 'herp' => 'derp'),
-        vec['shape[herp]'],
-      ),
       'shape with incorrect optional field' => tuple(
         type_structure(C::class, 'TFlatShape'),
         shape(
@@ -387,6 +377,20 @@ public function getExampleInvalidTypes(
         vec['keyset<T>'],
       ),
     ];
+
+    if (HHVM_VERSION_ID >= 32300) {
+      $examples['shape with missing nullable field'] = tuple(
+        type_structure(C::class, 'TFlatShape'),
+        shape('someString' => 'foo'),
+        vec['shape[someNullable]'],
+      );
+      $examples['shape with extra fields'] = tuple(
+        type_structure(C::class, 'TShapeWithOneField'),
+        shape('someString' => 'string', 'herp' => 'derp'),
+        vec['shape[herp]'],
+      );
+    }
+    return $examples;
   }
 
   /**
@@ -450,17 +454,27 @@ public function getExampleValidCoercions(
         ['foo' => 123, 'bar' => 456],
         dict['foo' => '123', 'bar' => '456'],
       ),
-      'shape with extra fields' => tuple(
-        type_structure(C::class, 'TShapeWithOneField'),
-        shape('someString' => 'foo', 'herp' => 'derp'),
-        shape('someString' => 'foo'),
-      ),
       'shape with implicit subtyping and extra fields' => tuple(
         type_structure(C::class, 'TShapeWithOneFieldAndImplicitSubtypes'),
         shape('someString' => 'foo', 'herp' => 'derp'),
         shape('someString' => 'foo', 'herp' => 'derp'),
       ),
     ];
+
+    if (HHVM_VERSION_ID >= 32300) {
+      $coercions['shape with extra fields'] = tuple(
+        type_structure(C::class, 'TShapeWithOneField'),
+        shape('someString' => 'foo', 'herp' => 'derp'),
+        shape('someString' => 'foo'),
+      );
+    } else {
+      $coercions['shape with extra fields'] = tuple(
+        type_structure(C::class, 'TShapeWithOneField'),
+        shape('someString' => 'foo', 'herp' => 'derp'),
+        shape('someString' => 'foo', 'herp' => 'derp'),
+      );
+    }
+
     return Dict\map(
       $this->getExampleValidTypes(),
       $tuple ==> {