Fix env variable remove on Windows

Removing env variable failed on uninstallation on Windows if the env
variable value had @TargetDir@ in path. File separators got changed
from Windows style to unix style.
Update documentation to inform users to use '\\' as separators when
setting a path as environment variable.

Tested with following values (component.addElevatedOperation(...)
in components.qs):
"@TargetDir@\\lib\\system\\qtplugins"
"not_a_path_but_variable_with_slash_\\qtplugins"
"not_a_path_but_variable_with_slash_/qtplugins"
"%SystemRoot%\\lib\\system\\qtplugins"
"12345"

Task-number: QTIFW-1148
Change-Id: Iaa48d890e70afdbe56bbf389dd4994d5ae91b316
Reviewed-by: Katja Marttila <katja.marttila@qt.io>

1 files changed, 12 insertions, 2 deletions

diff --git a/src/libs/installer/environmentvariablesoperation.cpp b/src/libs/installer/environmentvariablesoperation.cpp
index 006ea3762..1f3b56d52 100644
--- a/src/libs/installer/environmentvariablesoperation.cpp
+++ b/src/libs/installer/environmentvariablesoperation.cpp
@@ -152,8 +152,18 @@ UpdateOperation::Error undoSetting(const QString &regPath,
         SettingsType registry(regPath, QSettingsWrapper::NativeFormat);
         actual = registry.value(name).toString();
     }
-    if (actual != value) //key changed, don't undo
-        return UpdateOperation::UserDefinedError;
+
+    if (actual != value)
+    {
+        //For unknown reason paths with @TargetDir@ variable get modified
+        //so that Windows file separators get replaced with unix style separators,
+        //fix separators before matching to actual value in register
+        QString tempValue = value;
+        QString fixedValue = tempValue.replace(QLatin1Char('/'), QLatin1Char('\\'));
+
+        if (actual != fixedValue) //key changed, don't undo
+            return UpdateOperation::UserDefinedError;
+    }
 
     bool error = false;
     if (handleRegExpandSz(regPath, name, oldValue, errorString, &error))