Bleeding edge - detect stub file added multiple times

Author: ondrejmirtes

conf/bleedingEdge.neon

@@ -8,5 +8,6 @@ parameters:
 		unusedClassElements: true
 		readComposerPhpVersion: true
 		dateTimeInstantiation: true
+		detectDuplicateStubFiles: true
 	stubFiles:
 		- ../stubs/SplObjectStorage.stub

conf/config.neon

@@ -21,6 +21,7 @@ parameters:
 		unusedClassElements: false
 		readComposerPhpVersion: false
 		dateTimeInstantiation: false
+		detectDuplicateStubFiles: false
 	fileExtensions:
 		- php
 	checkAlwaysTrueCheckTypeFunctionCall: false
@@ -165,8 +166,9 @@ parametersSchema:
 		nullCoalesce: bool(),
 		fileWhitespace: bool(),
 		unusedClassElements: bool(),
-		readComposerPhpVersion: bool()
-		dateTimeInstantiation: bool()
+		readComposerPhpVersion: bool(),
+		dateTimeInstantiation: bool(),
+		detectDuplicateStubFiles: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAlwaysTrueCheckTypeFunctionCall: bool()

src/Command/CommandHelper.php

@@ -385,7 +385,19 @@ public static function begin(
 			throw new \PHPStan\Command\InceptionNotSuccessfulException();
 		}
 
+		$alreadyAddedStubFiles = [];
 		foreach ($container->getParameter('stubFiles') as $stubFile) {
+			if (
+				$container->getParameter('featureToggles')['detectDuplicateStubFiles']
+				&& array_key_exists($stubFile, $alreadyAddedStubFiles)
+			) {
+				$errorOutput->writeLineFormatted(sprintf('Stub file %s is added multiple times.', $stubFile));
+
+				throw new \PHPStan\Command\InceptionNotSuccessfulException();
+			}
+
+			$alreadyAddedStubFiles[$stubFile] = true;
+
 			if (is_file($stubFile)) {
 				continue;
 			}