diff --git a/setup/ModuleInstallationRepository.php b/setup/ModuleInstallationRepository.php
index 63bd984d4..1eeaa73fc 100644
--- a/setup/ModuleInstallationRepository.php
+++ b/setup/ModuleInstallationRepository.php
@@ -140,7 +140,8 @@ SQL;
 		}
 
 		SetupLog::Info(__METHOD__, null, ["product_name" => $aResult['product_name'], "product_version" => $aResult['product_version']]);
-		return empty($aResult) ? false : $aResult;
+
+		return count($aResult) == 0 ? false : $aResult;
 	}
 
 	private function ComputeInstalledModules(array $aSelectInstall): array
diff --git a/setup/compiler.class.inc.php b/setup/compiler.class.inc.php
index 38a86d45c..edbc37214 100644
--- a/setup/compiler.class.inc.php
+++ b/setup/compiler.class.inc.php
@@ -21,8 +21,8 @@
 use Combodo\iTop\Application\Branding;
 use Combodo\iTop\Application\WebPage\iTopWebPage;
 use Combodo\iTop\Application\WebPage\Page;
-use Combodo\iTop\DesignElement;
 use Combodo\iTop\DesignDocument;
+use Combodo\iTop\DesignElement;
 
 require_once(APPROOT.'setup/setuputils.class.inc.php');
 require_once(APPROOT.'setup/modelfactory.class.inc.php');
@@ -3359,6 +3359,8 @@ EOF;
 
 		$bDataXmlPrecompiledFileExists = false;
 		clearstatcache();
+
+		$iDataXmlFileLastModified = 0;
 		if (!empty($sPrecompiledFileUri)) {
 			$sDataXmlProvidedPrecompiledFile = $sTempTargetDir.DIRECTORY_SEPARATOR.$sPrecompiledFileUri;
 			$bDataXmlPrecompiledFileExists = file_exists($sDataXmlProvidedPrecompiledFile) ;
diff --git a/setup/moduleinstaller.class.inc.php b/setup/moduleinstaller.class.inc.php
index 0815fd4ba..a560141b3 100644
--- a/setup/moduleinstaller.class.inc.php
+++ b/setup/moduleinstaller.class.inc.php
@@ -130,6 +130,7 @@ abstract class ModuleInstallerAPI
 					if (in_array($sTo, $aNewValues)) {
 						$sEnumCol = $oAttDef->Get("sql");
 						$aFields = CMDBSource::QueryToArray("SHOW COLUMNS FROM `$sTableName` WHERE Field = '$sEnumCol'");
+						$aCurrentValues = [];
 						if (isset($aFields[0]['Type'])) {
 							$sColType = $aFields[0]['Type'];
 							// Note: the parsing should rely on str_getcsv (requires PHP 5.3) to cope with escaped string
diff --git a/setup/parameters.class.inc.php b/setup/parameters.class.inc.php
index bb22e2889..3426341c8 100644
--- a/setup/parameters.class.inc.php
+++ b/setup/parameters.class.inc.php
@@ -107,7 +107,9 @@ class PHPParameters extends Parameters
 	{
 		if ($this->aData == null) {
 			require_once($sParametersFile);
-			$this->aData = $ITOP_PARAMS; // Defined in the file loaded just above
+			if (isset($ITOP_PARAMS)) {
+				$this->aData = $ITOP_PARAMS; // Defined in the file loaded just above
+			}
 		}
 	}
 }
diff --git a/setup/runtimeenv.class.inc.php b/setup/runtimeenv.class.inc.php
index 6147a64f7..7cb5ae692 100644
--- a/setup/runtimeenv.class.inc.php
+++ b/setup/runtimeenv.class.inc.php
@@ -347,6 +347,7 @@ class RunTimeEnvironment
 		//
 		$oFactory = new ModelFactory($sSourceDirFull);
 		$aModulesToCompile = $this->GetMFModulesToCompile($sSourceEnv, $sSourceDir);
+		$oModule = null;
 		foreach ($aModulesToCompile as $oModule) {
 			if ($oModule instanceof MFDeltaModule) {
 				// Just before loading the delta, let's save an image of the datamodel
@@ -356,7 +357,7 @@ class RunTimeEnvironment
 			$oFactory->LoadModule($oModule);
 		}
 
-		if ($oModule instanceof MFDeltaModule) {
+		if (!is_null($oModule) && ($oModule instanceof MFDeltaModule)) {
 			// A delta was loaded, let's save a second copy of the datamodel
 			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sTargetEnv.'-with-delta.xml');
 		} else {
@@ -667,7 +668,8 @@ class RunTimeEnvironment
 			$aResult['datamodel_version'] = $aResult['product_version'];
 		}
 		$this->log_info("GetApplicationVersion returns: product_name: ".$aResult['product_name'].', product_version: '.$aResult['product_version']);
-		return empty($aResult) ? false : $aResult;
+
+		return count($aResult) == 0 ? false : $aResult;
 	}
 
 	public static function MakeDirSafe($sDir)
@@ -963,7 +965,7 @@ class RunTimeEnvironment
 		foreach ($aPreviouslyLoadedFiles as $sFileRelativePath) {
 			$sFileName = APPROOT.$sFileRelativePath;
 			SetupLog::Info("Loading file: $sFileName (just to get the keys mapping)");
-			if (empty($sFileName) || !file_exists($sFileName)) {
+			if (!file_exists($sFileName)) {
 				throw(new Exception("File $sFileName does not exist"));
 			}
 
@@ -975,7 +977,7 @@ class RunTimeEnvironment
 		foreach ($aFiles as $sFileRelativePath) {
 			$sFileName = APPROOT.$sFileRelativePath;
 			SetupLog::Info("Loading file: $sFileName");
-			if (empty($sFileName) || !file_exists($sFileName)) {
+			if (!file_exists($sFileName)) {
 				throw(new Exception("File $sFileName does not exist"));
 			}
 
diff --git a/setup/setuputils.class.inc.php b/setup/setuputils.class.inc.php
index 3706d3bca..6bce7ba82 100644
--- a/setup/setuputils.class.inc.php
+++ b/setup/setuputils.class.inc.php
@@ -254,32 +254,23 @@ class SetupUtils
 
 		if (!utils::IsModeCLI()) {
 			$sUploadTmpDir = self::GetUploadTmpDir();
-			if (empty($sUploadTmpDir)) {
-				$sUploadTmpDir = '/tmp';
-				$aResult[] = new CheckResult(
-					CheckResult::WARNING,
-					"Temporary directory for files upload is not defined (upload_tmp_dir), assuming that $sUploadTmpDir is used."
-				);
-			}
 			// check that the upload directory is indeed writable from PHP
-			if (!empty($sUploadTmpDir)) {
-				if (!file_exists($sUploadTmpDir)) {
+			if (!file_exists($sUploadTmpDir)) {
+				$aResult[] = new CheckResult(
+					CheckResult::ERROR,
+					"Temporary directory for files upload ($sUploadTmpDir) does not exist or cannot be read by PHP."
+				);
+			} else {
+				if (!is_writable($sUploadTmpDir)) {
 					$aResult[] = new CheckResult(
 						CheckResult::ERROR,
-						"Temporary directory for files upload ($sUploadTmpDir) does not exist or cannot be read by PHP."
+						"Temporary directory for files upload ($sUploadTmpDir) is not writable."
 					);
 				} else {
-					if (!is_writable($sUploadTmpDir)) {
-						$aResult[] = new CheckResult(
-							CheckResult::ERROR,
-							"Temporary directory for files upload ($sUploadTmpDir) is not writable."
-						);
-					} else {
-						$aResult[] = new CheckResult(
-							CheckResult::TRACE,
-							"Info - Temporary directory for files upload ($sUploadTmpDir) is writable."
-						);
-					}
+					$aResult[] = new CheckResult(
+						CheckResult::TRACE,
+						"Info - Temporary directory for files upload ($sUploadTmpDir) is writable."
+					);
 				}
 			}
 		}
diff --git a/setup/xmldataloader.class.inc.php b/setup/xmldataloader.class.inc.php
index 01085a30e..fb53e2e76 100644
--- a/setup/xmldataloader.class.inc.php
+++ b/setup/xmldataloader.class.inc.php
@@ -353,6 +353,7 @@ class XMLDataLoader
 			foreach ($oObjList as $oTargetObj) {
 				$bChanged = false;
 				$sClass = get_class($oTargetObj);
+				$iExtKey = -1;
 				foreach (MetaModel::ListAttributeDefs($sClass) as $sAttCode => $oAttDef) {
 					if (($oAttDef->IsExternalKey()) && ($oTargetObj->Get($sAttCode) < 0)) { // Convention unresolved key = negative
 						$sTargetClass = $oAttDef->GetTargetClass();