diff --git a/src/Framework/Constraint/String/StringContains.php b/src/Framework/Constraint/String/StringContains.php
index 7ba71587e58..7a805edde38 100644
--- a/src/Framework/Constraint/String/StringContains.php
+++ b/src/Framework/Constraint/String/StringContains.php
@@ -127,7 +127,7 @@ private function getDetectedEncoding(mixed $other): string
 
         $detectedEncoding = mb_detect_encoding($other, null, true);
 
-        if (!$detectedEncoding) {
+        if ($detectedEncoding === false) {
             return 'Encoding detection failed';
         }
 
diff --git a/src/Framework/TestRunner.php b/src/Framework/TestRunner.php
index c7f31d7c1d1..f6bf682af2e 100644
--- a/src/Framework/TestRunner.php
+++ b/src/Framework/TestRunner.php
@@ -451,7 +451,7 @@ private function saveConfigurationForChildProcess(): string
     {
         $path = tempnam(sys_get_temp_dir(), 'phpunit_');
 
-        if (!$path) {
+        if ($path === false) {
             throw new ProcessIsolationException;
         }
 
diff --git a/src/Metadata/Api/DataProvider.php b/src/Metadata/Api/DataProvider.php
index 2774f63bc89..93e85770dd4 100644
--- a/src/Metadata/Api/DataProvider.php
+++ b/src/Metadata/Api/DataProvider.php
@@ -236,7 +236,7 @@ private function dataProvidedByTestWithAnnotation(string $className, string $met
     {
         $docComment = (new ReflectionMethod($className, $methodName))->getDocComment();
 
-        if (!$docComment) {
+        if ($docComment === false) {
             return null;
         }
 
diff --git a/src/Runner/PhptTestCase.php b/src/Runner/PhptTestCase.php
index 20577a694ec..4a6636df787 100644
--- a/src/Runner/PhptTestCase.php
+++ b/src/Runner/PhptTestCase.php
@@ -217,8 +217,8 @@ public function run(): void
                 $failure = new PhptAssertionFailedError(
                     $e->getMessage(),
                     0,
-                    $trace[0]['file'],
-                    $trace[0]['line'],
+                    (string) $trace[0]['file'],
+                    (int) $trace[0]['line'],
                     $trace,
                     $comparisonFailure ? $diff : '',
                 );
diff --git a/src/TextUI/Application.php b/src/TextUI/Application.php
index fc64589c6a8..47a917b1368 100644
--- a/src/TextUI/Application.php
+++ b/src/TextUI/Application.php
@@ -332,7 +332,7 @@ private function buildCliConfiguration(array $argv): CliConfiguration
 
     private function loadXmlConfiguration(false|string $configurationFile): XmlConfiguration
     {
-        if (!$configurationFile) {
+        if ($configurationFile === false) {
             return DefaultConfiguration::create();
         }
 
@@ -387,7 +387,7 @@ private function executeCommandsThatOnlyRequireCliConfiguration(CliConfiguration
         }
 
         if ($cliConfiguration->migrateConfiguration()) {
-            if (!$configurationFile) {
+            if ($configurationFile === false) {
                 $this->exitWithErrorMessage('No configuration file found to migrate');
             }
 
diff --git a/src/TextUI/Configuration/Builder.php b/src/TextUI/Configuration/Builder.php
index 48fc057880e..6ada9b4a1c9 100644
--- a/src/TextUI/Configuration/Builder.php
+++ b/src/TextUI/Configuration/Builder.php
@@ -33,7 +33,7 @@ public function build(array $argv): Configuration
             $configurationFile = (new XmlConfigurationFileFinder)->find($cliConfiguration);
             $xmlConfiguration  = DefaultConfiguration::create();
 
-            if ($configurationFile) {
+            if ($configurationFile !== false) {
                 $xmlConfiguration = (new Loader)->load($configurationFile);
             }
 
diff --git a/src/TextUI/Configuration/Cli/XmlConfigurationFileFinder.php b/src/TextUI/Configuration/Cli/XmlConfigurationFileFinder.php
index 55a89c1e185..79cbfd15e60 100644
--- a/src/TextUI/Configuration/Cli/XmlConfigurationFileFinder.php
+++ b/src/TextUI/Configuration/Cli/XmlConfigurationFileFinder.php
@@ -27,7 +27,7 @@ public function find(Configuration $configuration): false|string
             if (is_dir($configuration->configurationFile())) {
                 $candidate = $this->configurationFileInDirectory($configuration->configurationFile());
 
-                if ($candidate) {
+                if ($candidate !== false) {
                     return $candidate;
                 }
 
@@ -40,7 +40,7 @@ public function find(Configuration $configuration): false|string
         if ($useDefaultConfiguration) {
             $candidate = $this->configurationFileInDirectory(getcwd());
 
-            if ($candidate) {
+            if ($candidate !== false) {
                 return $candidate;
             }
         }
diff --git a/src/TextUI/Configuration/Xml/Loader.php b/src/TextUI/Configuration/Xml/Loader.php
index 3b8c8b7c5e6..991618d9552 100644
--- a/src/TextUI/Configuration/Xml/Loader.php
+++ b/src/TextUI/Configuration/Xml/Loader.php
@@ -474,7 +474,7 @@ private function codeCoverage(string $filename, DOMXPath $xpath): CodeCoverage
         );
     }
 
-    private function getBoolean(string $value, bool|string $default): bool|string
+    private function getBoolean(string $value, bool $default): bool
     {
         if (strtolower($value) === 'false') {
             return false;
@@ -487,6 +487,19 @@ private function getBoolean(string $value, bool|string $default): bool|string
         return $default;
     }
 
+    private function getValue(string $value): bool|string
+    {
+        if (strtolower($value) === 'false') {
+            return false;
+        }
+
+        if (strtolower($value) === 'true') {
+            return true;
+        }
+
+        return $value;
+    }
+
     private function readFilterDirectories(string $filename, DOMXPath $xpath, string $query): FilterDirectoryCollection
     {
         $directories = [];
@@ -556,7 +569,7 @@ private function getBooleanAttribute(DOMElement $element, string $attribute, boo
             return $default;
         }
 
-        return (bool) $this->getBoolean(
+        return $this->getBoolean(
             $element->getAttribute($attribute),
             false,
         );
@@ -635,7 +648,7 @@ private function php(string $filename, DOMXPath $xpath): Php
 
             $constants[] = new Constant(
                 $const->getAttribute('name'),
-                $this->getBoolean($value, $value),
+                $this->getValue($value),
             );
         }
 
@@ -660,7 +673,7 @@ private function php(string $filename, DOMXPath $xpath): Php
                 $verbatim = false;
 
                 if ($var->hasAttribute('force')) {
-                    $force = (bool) $this->getBoolean($var->getAttribute('force'), false);
+                    $force = $this->getBoolean($var->getAttribute('force'), false);
                 }
 
                 if ($var->hasAttribute('verbatim')) {
@@ -668,7 +681,7 @@ private function php(string $filename, DOMXPath $xpath): Php
                 }
 
                 if (!$verbatim) {
-                    $value = $this->getBoolean($value, $value);
+                    $value = $this->getValue($value);
                 }
 
                 $variables[$array][] = new Variable($name, $value, $force);