Allow calling installer.setValue() with an empty string as the value

Calls like

  installer.setValue("RunProgram", "");

would fail if there was no previous setValue() call which set the
variable to a non-empty string.

In PackageManagerCoreData, the variables of the installer which are
accessible via installer.setValue and installer.value are managed in two
data structures:

* m_variables contains all variables which were set at runtime, via
  installer.setValue
* m_settings contains all variables as defined in the XML configuration
  file.

When calling installer.value(), it would first consider m_variables and
if the given variable name is not in that structure, it falls back to
m_settings.

What happened for calls like 'installer.setValue("RunProgram", "");' was
that the code tries to detect whether the variable already has the
specified value -- and only if it doesn't, the variable is set. To test
if the variable has the specified value, it would simply check
m_variables.value(key) and compare it with the given new value. However,
if the key was never set, 'value()' returns an empty string -- which is
equal to the new value, and hence PackageManagerCoreData::setValue()
returned false.

Fix this by first verifying that the given key exists in the m_variables
object at all before bothering to check what m_variables.value()
returns.

Change-Id: I8a2bcb74e52e05f1454945628bcf372445c91a17
Reviewed-by: Katja Marttila <katja.marttila@theqtcompany.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libs/installer/packagemanagercoredata.cpp b/src/libs/installer/packagemanagercoredata.cpp
index 671717d0b..3444e0247 100644
--- a/src/libs/installer/packagemanagercoredata.cpp
+++ b/src/libs/installer/packagemanagercoredata.cpp
@@ -160,7 +160,7 @@ bool PackageManagerCoreData::contains(const QString &key) const
 
 bool PackageManagerCoreData::setValue(const QString &key, const QString &normalizedValue)
 {
-    if (m_variables.value(key) == normalizedValue)
+    if (m_variables.contains(key) && m_variables.value(key) == normalizedValue)
         return false;
     m_variables.insert(key, normalizedValue);
     return true;