Added different message to distinguish between two cases:

a) the value at the path is of the wrong type
b) the path does not exist

.

Author: Ivan Kurnosov

src/Psl/Type/Exception/AssertException.php

@@ -17,18 +17,28 @@ final class AssertException extends Exception
     /**
      * @param list<string> $paths
      */
-    private function __construct(string $actual, string $expected, array $paths = [], ?Throwable $previous = null)
+    private function __construct(?string $actual, string $expected, array $paths = [], ?Throwable $previous = null)
     {
         $first = $previous instanceof Exception ? $previous->getFirstFailingActualType() : $actual;
 
-        parent::__construct(
-            Str\format(
+        if ($first !== null) {
+            $message = Str\format(
                 'Expected "%s", got "%s"%s.',
                 $expected,
                 $first,
-                $paths ? ' at path "' . Str\join($paths, '.') . '"' : ''
-            ),
-            $actual,
+                $paths ? ' at path "' . Str\join($paths, '.') . '"' : '',
+            );
+        } else {
+            $message = Str\format(
+                'Expected "%s", received no value at path "%s".',
+                $expected,
+                Str\join($paths, '.'),
+            );
+        }
+
+        parent::__construct(
+            $message,
+            $actual ?? 'null',
             $paths,
             $previous
         );
@@ -51,4 +61,14 @@ public static function withValue(
 
         return new self(get_debug_type($value), $expected_type, Vec\filter_nulls($paths), $previous);
     }
+
+    public static function withoutValue(
+        string $expected_type,
+        ?string $path = null,
+        ?Throwable $previous = null
+    ): self {
+        $paths = $previous instanceof Exception ? [$path, ...$previous->getPaths()] : [$path];
+
+        return new self(null, $expected_type, Vec\filter_nulls($paths), $previous);
+    }
 }

src/Psl/Type/Exception/CoercionException.php

@@ -17,19 +17,30 @@ final class CoercionException extends Exception
     /**
      * @param list<string> $paths
      */
-    private function __construct(string $actual, string $target, array $paths = [], ?Throwable $previous = null)
+    private function __construct(?string $actual, string $target, array $paths = [], ?Throwable $previous = null)
     {
         $first = $previous instanceof Exception ? $previous->getFirstFailingActualType() : $actual;
 
-        parent::__construct(
-            Str\format(
+        if ($first !== null) {
+            $message = Str\format(
                 'Could not coerce "%s" to type "%s"%s%s.',
                 $first,
                 $target,
                 $paths ? ' at path "' . Str\join($paths, '.') . '"' : '',
                 $previous && !$previous instanceof self ? ': ' . $previous->getMessage() : '',
-            ),
-            $actual,
+            );
+        } else {
+            $message = Str\format(
+                'Could not coerce to type "%s" at path "%s" as the value was not passed%s.',
+                $target,
+                Str\join($paths, '.'),
+                $previous && !$previous instanceof self ? ': ' . $previous->getMessage() : '',
+            );
+        }
+
+        parent::__construct(
+            $message,
+            $actual ?? 'null',
             $paths,
             $previous
         );
@@ -52,4 +63,14 @@ public static function withValue(
 
         return new self(get_debug_type($value), $target, Vec\filter_nulls($paths), $previous);
     }
+
+    public static function withoutValue(
+        string $target,
+        ?string $path = null,
+        ?Throwable $previous = null
+    ): self {
+        $paths = $previous instanceof Exception ? [$path, ...$previous->getPaths()] : [$path];
+
+        return new self(null, $target, Vec\filter_nulls($paths), $previous);
+    }
 }

src/Psl/Type/Internal/ShapeType.php

@@ -144,7 +144,7 @@ private function coerceIterable(mixed $value): array
                     continue;
                 }
 
-                throw CoercionException::withValue(null, $this->toString(), PathExpression::path($element));
+                throw CoercionException::withoutValue($this->toString(), PathExpression::path($element));
             }
         } catch (CoercionException $e) {
             throw match (true) {
@@ -196,7 +196,7 @@ public function assert(mixed $value): array
                     continue;
                 }
 
-                throw AssertException::withValue(null, $this->toString(), PathExpression::path($element));
+                throw AssertException::withoutValue($this->toString(), PathExpression::path($element));
             }
         } catch (AssertException $e) {
             throw match (true) {

tests/unit/Type/ShapeTypeTest.php

@@ -216,7 +216,7 @@ public static function provideAssertExceptionExpectations(): iterable
                 'name' => Type\string(),
             ]),
             [],
-            'Expected "array{\'name\': string}", got "null" at path "name".'
+            'Expected "array{\'name\': string}", received no value at path "name".'
         ];
         yield 'invalid key' => [
             Type\shape([
@@ -247,7 +247,7 @@ public static function provideCoerceExceptionExpectations(): iterable
                 'name' => Type\string(),
             ]),
             [],
-            'Could not coerce "null" to type "array{\'name\': string}" at path "name".'
+            'Could not coerce to type "array{\'name\': string}" at path "name" as the value was not passed.'
         ];
         yield 'invalid key' => [
             Type\shape([
@@ -295,7 +295,7 @@ public static function provideCoerceExceptionExpectations(): iterable
             (static function () {
                 yield null => 'nope';
             })(),
-            'Could not coerce "null" to type "array{\'id\': int}" at path "id".'
+            'Could not coerce to type "array{\'id\': int}" at path "id" as the value was not passed.'
         ];
         yield 'iterator yielding object key' => [
             Type\shape([
@@ -305,7 +305,7 @@ public static function provideCoerceExceptionExpectations(): iterable
                 yield (new class () {
                 }) => 'nope';
             })(),
-            'Could not coerce "null" to type "array{\'id\': int}" at path "id".'
+            'Could not coerce to type "array{\'id\': int}" at path "id" as the value was not passed.'
         ];
     }