Improve date() return types

conf/config.neon

@@ -1272,6 +1272,9 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\DateFunctionReturnTypeHelper
+
 	-
 		class: PHPStan\Type\Php\DateFormatFunctionReturnTypeExtension
 		tags:

src/Type/Php/DateFormatFunctionReturnTypeExtension.php

@@ -3,7 +3,6 @@
 namespace PHPStan\Type\Php;
 
 use PhpParser\Node\Expr\FuncCall;
-use PhpParser\Node\Name\FullyQualified;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
@@ -14,6 +13,10 @@
 class DateFormatFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
 {
 
+	public function __construct(private DateFunctionReturnTypeHelper $dateFunctionReturnTypeHelper)
+	{
+	}
+
 	public function isFunctionSupported(FunctionReflection $functionReflection): bool
 	{
 		return $functionReflection->getName() === 'date_format';
@@ -23,16 +26,15 @@ public function getTypeFromFunctionCall(
 		FunctionReflection $functionReflection,
 		FuncCall $functionCall,
 		Scope $scope,
-	): Type
+	): ?Type
 	{
 		if (count($functionCall->getArgs()) < 2) {
 			return new StringType();
 		}
 
-		return $scope->getType(
-			new FuncCall(new FullyQualified('date'), [
-				$functionCall->getArgs()[1],
-			]),
+		return $this->dateFunctionReturnTypeHelper->getTypeFromFormatType(
+			$scope->getType($functionCall->getArgs()[1]->value),
+			true,
 		);
 	}
 

src/Type/Php/DateFormatMethodReturnTypeExtension.php

@@ -3,9 +3,7 @@
 namespace PHPStan\Type\Php;
 
 use DateTimeInterface;
-use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\MethodCall;
-use PhpParser\Node\Name\FullyQualified;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\MethodReflection;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
@@ -16,6 +14,10 @@
 class DateFormatMethodReturnTypeExtension implements DynamicMethodReturnTypeExtension
 {
 
+	public function __construct(private DateFunctionReturnTypeHelper $dateFunctionReturnTypeHelper)
+	{
+	}
+
 	public function getClass(): string
 	{
 		return DateTimeInterface::class;
@@ -26,16 +28,15 @@ public function isMethodSupported(MethodReflection $methodReflection): bool
 		return $methodReflection->getName() === 'format';
 	}
 
-	public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): Type
+	public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): ?Type
 	{
 		if (count($methodCall->getArgs()) === 0) {
 			return new StringType();
 		}
 
-		return $scope->getType(
-			new FuncCall(new FullyQualified('date'), [
-				$methodCall->getArgs()[0],
-			]),
+		return $this->dateFunctionReturnTypeHelper->getTypeFromFormatType(
+			$scope->getType($methodCall->getArgs()[0]->value),
+			true,
 		);
 	}
 

src/Type/Php/DateFunctionReturnTypeExtension.php

@@ -5,23 +5,17 @@
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
-use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
-use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
-use PHPStan\Type\Accessory\AccessoryNumericStringType;
-use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\IntersectionType;
-use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
-use PHPStan\Type\TypeCombinator;
-use PHPStan\Type\UnionType;
 use function count;
-use function date;
-use function sprintf;
 
 class DateFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
 {
 
+	public function __construct(private DateFunctionReturnTypeHelper $dateFunctionReturnTypeHelper)
+	{
+	}
+
 	public function isFunctionSupported(FunctionReflection $functionReflection): bool
 	{
 		return $functionReflection->getName() === 'date';
@@ -31,101 +25,16 @@ public function getTypeFromFunctionCall(
 		FunctionReflection $functionReflection,
 		FuncCall $functionCall,
 		Scope $scope,
-	): Type
+	): ?Type
 	{
 		if (count($functionCall->getArgs()) === 0) {
-			return new StringType();
-		}
-		$argType = $scope->getType($functionCall->getArgs()[0]->value);
-		$constantStrings = $argType->getConstantStrings();
-
-		if (count($constantStrings) === 0) {
-			return new StringType();
-		}
-
-		if (count($constantStrings) === 1) {
-			$constantString = $constantStrings[0]->getValue();
-
-			// see see https://www.php.net/manual/en/datetime.format.php
-			switch ($constantString) {
-				case 'd':
-					return $this->buildNumericRangeType(1, 31, true);
-				case 'j':
-					return $this->buildNumericRangeType(1, 31, false);
-				case 'N':
-					return $this->buildNumericRangeType(1, 7, false);
-				case 'w':
-					return $this->buildNumericRangeType(0, 6, false);
-				case 'm':
-					return $this->buildNumericRangeType(1, 12, true);
-				case 'n':
-					return $this->buildNumericRangeType(1, 12, false);
-				case 't':
-					return $this->buildNumericRangeType(28, 31, false);
-				case 'L':
-					return $this->buildNumericRangeType(0, 1, false);
-				case 'g':
-					return $this->buildNumericRangeType(1, 12, false);
-				case 'G':
-					return $this->buildNumericRangeType(0, 23, false);
-				case 'h':
-					return $this->buildNumericRangeType(1, 12, true);
-				case 'H':
-					return $this->buildNumericRangeType(0, 23, true);
-				case 'I':
-					return $this->buildNumericRangeType(0, 1, false);
-			}
-		}
-
-		$types = [];
-		foreach ($constantStrings as $constantString) {
-			$types[] = new ConstantStringType(date($constantString->getValue()));
-		}
-
-		$type = TypeCombinator::union(...$types);
-		if ($type->isNumericString()->yes()) {
-			return new IntersectionType([
-				new StringType(),
-				new AccessoryNumericStringType(),
-			]);
-		}
-
-		if ($type->isNonFalsyString()->yes()) {
-			return new IntersectionType([
-				new StringType(),
-				new AccessoryNonFalsyStringType(),
-			]);
-		}
-
-		if ($type->isNonEmptyString()->yes()) {
-			return new IntersectionType([
-				new StringType(),
-				new AccessoryNonEmptyStringType(),
-			]);
-		}
-
-		if ($type->isNonEmptyString()->no()) {
-			return new ConstantStringType('');
-		}
-
-		return new StringType();
-	}
-
-	private function buildNumericRangeType(int $min, int $max, bool $zeroPad): Type
-	{
-		$types = [];
-
-		for ($i = $min; $i <= $max; $i++) {
-			$string = (string) $i;
-
-			if ($zeroPad) {
-				$string = sprintf('%02s', $string);
-			}
-
-			$types[] = new ConstantStringType($string);
+			return null;
 		}
 
-		return new UnionType($types);
+		return $this->dateFunctionReturnTypeHelper->getTypeFromFormatType(
+			$scope->getType($functionCall->getArgs()[0]->value),
+			false,
+		);
 	}
 
 }

src/Type/Php/DateFunctionReturnTypeHelper.php

@@ -0,0 +1,114 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
+use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
+use PHPStan\Type\Accessory\AccessoryNumericStringType;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\IntersectionType;
+use PHPStan\Type\StringType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\UnionType;
+use function count;
+use function date;
+use function is_numeric;
+use function str_pad;
+use const STR_PAD_LEFT;
+
+class DateFunctionReturnTypeHelper
+{
+
+	public function getTypeFromFormatType(Type $formatType, bool $useMicrosec): ?Type
+	{
+		$types = [];
+		foreach ($formatType->getConstantStrings() as $formatString) {
+			$types[] = $this->buildReturnTypeFromFormat($formatString->getValue(), $useMicrosec);
+		}
+
+		if (count($types) === 0) {
+			$types[] = $formatType->isNonEmptyString()->yes()
+				? new IntersectionType([new StringType(), new AccessoryNonEmptyStringType()])
+				: new StringType();
+		}
+
+		$type = TypeCombinator::union(...$types);
+
+		if ($type->isNumericString()->no() && $formatType->isNonEmptyString()->yes()) {
+			$type = TypeCombinator::union($type, new IntersectionType([
+				new StringType(), new AccessoryNonEmptyStringType(),
+			]));
+		}
+
+		return $type;
+	}
+
+	public function buildReturnTypeFromFormat(string $formatString, bool $useMicrosec): Type
+	{
+		// see see https://www.php.net/manual/en/datetime.format.php
+		switch ($formatString) {
+			case 'd':
+				return $this->buildNumericRangeType(1, 31, true);
+			case 'j':
+				return $this->buildNumericRangeType(1, 31, false);
+			case 'N':
+				return $this->buildNumericRangeType(1, 7, false);
+			case 'w':
+				return $this->buildNumericRangeType(0, 6, false);
+			case 'm':
+				return $this->buildNumericRangeType(1, 12, true);
+			case 'n':
+				return $this->buildNumericRangeType(1, 12, false);
+			case 't':
+				return $this->buildNumericRangeType(28, 31, false);
+			case 'L':
+				return $this->buildNumericRangeType(0, 1, false);
+			case 'g':
+				return $this->buildNumericRangeType(1, 12, false);
+			case 'G':
+				return $this->buildNumericRangeType(0, 23, false);
+			case 'h':
+				return $this->buildNumericRangeType(1, 12, true);
+			case 'H':
+				return $this->buildNumericRangeType(0, 23, true);
+			case 'I':
+				return $this->buildNumericRangeType(0, 1, false);
+			case 'u':
+				return $useMicrosec
+					? new IntersectionType([new StringType(), new AccessoryNonFalsyStringType()])
+					: new ConstantStringType('000000');
+		}
+
+		$date = date($formatString);
+
+		// If parameter string is not included, returned as ConstantStringType
+		if ($date === $formatString) {
+			return new ConstantStringType($date);
+		}
+
+		if (is_numeric($date)) {
+			return new IntersectionType([new StringType(), new AccessoryNumericStringType()]);
+		}
+
+		return new IntersectionType([new StringType(), new AccessoryNonFalsyStringType()]);
+	}
+
+	private function buildNumericRangeType(int $min, int $max, bool $zeroPad): Type
+	{
+		$types = [];
+
+		for ($i = $min; $i <= $max; $i++) {
+			$string = (string) $i;
+
+			if ($zeroPad) {
+				$string = str_pad($string, 2, '0', STR_PAD_LEFT);
+			}
+
+			$types[] = new ConstantStringType($string);
+		}
+
+		return new UnionType($types);
+	}
+
+}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1450,6 +1450,8 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10037.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/PhpDoc/data/bug-10594.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/set-type-type-specifying.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10468.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6613.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/bug-10468.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Bug6613;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param non-empty-string $non_empty_format
+ */
+function foo(string $format, string $non_empty_format): void
+{
+	assertType("string", date($format));
+	assertType("non-empty-string", date($non_empty_format));
+}

tests/PHPStan/Analyser/data/bug-6613.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Bug6613;
+
+use function PHPStan\Testing\assertType;
+
+function (\DateTime $dt) {
+	assertType("'000000'", date('u'));
+	assertType('non-falsy-string', date_format($dt, 'u'));
+	assertType('non-falsy-string', $dt->format('u'));
+};