Fix implode() for non-empty-string return type

phpstan · Jul 14, 2021 · 520ae22 · 520ae22
1 parent 5eb96f5
commit 520ae22
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diff --git a/conf/config.neon b/conf/config.neon
@@ -1250,6 +1250,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\ImplodeFunctionReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicFunctionReturnTypeExtension
+
 	-
 		class: PHPStan\Type\Php\ParseUrlFunctionDynamicReturnTypeExtension
 		tags:

diff --git a/src/Type/Php/ImplodeFunctionReturnTypeExtension.php b/src/Type/Php/ImplodeFunctionReturnTypeExtension.php
@@ -0,0 +1,69 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
+use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\IntersectionType;
+use PHPStan\Type\StringType;
+
+class ImplodeFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
+{
+
+	public function isFunctionSupported(FunctionReflection $functionReflection): bool
+	{
+		return in_array($functionReflection->getName(), [
+			'implode',
+			'join',
+		], true);
+	}
+
+	public function getTypeFromFunctionCall(
+		FunctionReflection $functionReflection,
+		FuncCall $functionCall,
+		Scope $scope
+	): \PHPStan\Type\Type
+	{
+		$args = $functionCall->args;
+		if (count($args) === 1) {
+			$argType = $scope->getType($args[0]->value);
+			if ($argType->isArray()->yes()) {
+				if ($argType->isIterableAtLeastOnce()->yes() && $argType->getIterableValueType()->isNonEmptyString()->yes()) {
+					return new IntersectionType([
+						new StringType(),
+						new AccessoryNonEmptyStringType(),
+					]);
+				}
+
+				return new StringType();
+			}
+		}
+
+		if (count($args) !== 2) {
+			return new StringType();
+		}
+
+		$separatorType = $scope->getType($args[0]->value);
+		$arrayType = $scope->getType($args[1]->value);
+		if ($arrayType->isIterableAtLeastOnce()->yes()) {
+			if ($arrayType->getIterableValueType()->isNonEmptyString()->yes()) {
+				return new IntersectionType([
+					new StringType(),
+					new AccessoryNonEmptyStringType(),
+				]);
+			}
+			if ($separatorType->isNonEmptyString()->yes()) {
+				return new IntersectionType([
+					new StringType(),
+					new AccessoryNonEmptyStringType(),
+				]);
+			}
+		}
+
+		return new StringType();
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/data/non-empty-string.php b/tests/PHPStan/Analyser/data/non-empty-string.php
@@ -130,3 +130,92 @@ public function doEmpty2(string $s): void
 	}
 
 }
+
+class ImplodingStrings
+{
+
+	/**
+	 * @param array<string> $commonStrings
+	 */
+	public function doFoo(string $s, array $commonStrings): void
+	{
+		assertType('string', implode($s, $commonStrings));
+		assertType('string', implode(' ', $commonStrings));
+		assertType('string', implode('', $commonStrings));
+		assertType('string', implode($commonStrings));
+	}
+
+	/**
+	 * @param non-empty-array<string> $nonEmptyArrayWithStrings
+	 */
+	public function doFoo2(string $s, array $nonEmptyArrayWithStrings): void
+	{
+		assertType('string', implode($s, $nonEmptyArrayWithStrings));
+		assertType('string', implode('', $nonEmptyArrayWithStrings));
+		assertType('non-empty-string', implode(' ', $nonEmptyArrayWithStrings));
+		assertType('string', implode($nonEmptyArrayWithStrings));
+	}
+
+	/**
+	 * @param array<non-empty-string> $arrayWithNonEmptyStrings
+	 */
+	public function doFoo3(string $s, array $arrayWithNonEmptyStrings): void
+	{
+		assertType('string', implode($s, $arrayWithNonEmptyStrings));
+		assertType('string', implode('', $arrayWithNonEmptyStrings));
+		assertType('string', implode(' ', $arrayWithNonEmptyStrings));
+		assertType('string', implode($arrayWithNonEmptyStrings));
+	}
+
+	/**
+	 * @param non-empty-array<non-empty-string> $nonEmptyArrayWithNonEmptyStrings
+	 */
+	public function doFoo4(string $s, array $nonEmptyArrayWithNonEmptyStrings): void
+	{
+		assertType('non-empty-string', implode($s, $nonEmptyArrayWithNonEmptyStrings));
+		assertType('non-empty-string', implode('', $nonEmptyArrayWithNonEmptyStrings));
+		assertType('non-empty-string', implode(' ', $nonEmptyArrayWithNonEmptyStrings));
+		assertType('non-empty-string', implode($nonEmptyArrayWithNonEmptyStrings));
+	}
+
+	public function sayHello(): void
+	{
+		// coming from issue #5291
+		$s = array(1,2);
+
+		assertType('non-empty-string', implode("a", $s));
+	}
+
+	/**
+	 * @param non-empty-string $glue
+	 */
+	public function nonE($glue, array $a) {
+		// coming from issue #5291
+		if (empty($a)) {
+			return "xyz";
+		}
+
+		assertType('non-empty-string', implode($glue, $a));
+	}
+
+	public function sayHello2(): void
+	{
+		// coming from issue #5291
+		$s = array(1,2);
+
+		assertType('non-empty-string', join("a", $s));
+	}
+
+	/**
+	 * @param non-empty-string $glue
+	 */
+	public function nonE2($glue, array $a) {
+		// coming from issue #5291
+		if (empty($a)) {
+			return "xyz";
+		}
+
+		assertType('non-empty-string', join($glue, $a));
+	}
+
+}