chore(cleanup): don't use 0 as nullptr

Don't add Wzero-as-null-pointer-constant by default, since on older Qt
versions that we stil support and that our CI runs agains, Qt API themselves
cause warnings which lead to build errors all over the place.

Fix #6008

src/nexus.cpp

@@ -113,7 +113,7 @@ void Nexus::start()
 
 #ifdef Q_OS_MAC
     // TODO: still needed?
-    globalMenuBar = new QMenuBar(0);
+    globalMenuBar = new QMenuBar();
     dockMenu = new QMenu(globalMenuBar);
 
     viewMenu = globalMenuBar->addMenu(QString());

src/persistence/db/rawdatabase.cpp

@@ -738,7 +738,9 @@ void RawDatabase::process()
                     const QByteArray& blob = query.blobs[curParam + i];
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wold-style-cast"
-                    // SQLITE_STATIC uses old-style cast and comes from system headers, so can't be fixed by us
+#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
+                    // SQLITE_STATIC uses old-style cast and 0 as null pointer butcomes from system headers, so can't
+                    // be fixed by us
                     auto sqliteDataType = SQLITE_STATIC;
 #pragma GCC diagnostic pop
                     if (sqlite3_bind_blob(stmt, i + 1, blob.data(), blob.size(), sqliteDataType)

src/persistence/db/rawdatabase.h

@@ -39,7 +39,10 @@
 #define SQLITE_HAS_CODEC
 #define SQLITE_TEMP_STORE 2
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
 #include <sqlite3.h>
+#pragma GCC diagnostic pop
 
 using RowId = NamedType<int64_t, struct RowIdTag, Orderable>;
 Q_DECLARE_METATYPE(RowId);

src/platform/autorun_win.cpp

@@ -57,7 +57,7 @@ inline tstring currentRegistryKeyName()
 
 bool Platform::setAutorun(bool on)
 {
-    HKEY key = 0;
+    HKEY key = nullptr;
     if (RegOpenKeyEx(HKEY_CURRENT_USER, TEXT("Software\\Microsoft\\Windows\\CurrentVersion\\Run"),
                      0, KEY_ALL_ACCESS, &key)
         != ERROR_SUCCESS)
@@ -80,7 +80,7 @@ bool Platform::setAutorun(bool on)
 
 bool Platform::getAutorun()
 {
-    HKEY key = 0;
+    HKEY key = nullptr;
     if (RegOpenKeyEx(HKEY_CURRENT_USER, TEXT("Software\\Microsoft\\Windows\\CurrentVersion\\Run"),
                      0, KEY_ALL_ACCESS, &key)
         != ERROR_SUCCESS)
@@ -93,7 +93,7 @@ bool Platform::getAutorun()
     DWORD type = REG_SZ;
     bool result = false;
 
-    if (RegQueryValueEx(key, keyName.c_str(), 0, &type, const_cast<PBYTE>(reinterpret_cast<const unsigned char*>(path)), &length) == ERROR_SUCCESS
+    if (RegQueryValueEx(key, keyName.c_str(), nullptr, &type, const_cast<PBYTE>(reinterpret_cast<const unsigned char*>(path)), &length) == ERROR_SUCCESS
         && type == REG_SZ)
         result = true;
 

src/platform/camera/directshow.cpp

@@ -42,10 +42,10 @@
 
 static char* wcharToUtf8(wchar_t* w)
 {
-    int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);
+    int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, nullptr, 0, nullptr, nullptr);
     char* s = new char[l];
     if (s)
-        WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, 0, 0);
+        WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, nullptr, nullptr);
     return s;
 }
 
@@ -157,7 +157,7 @@ static IBaseFilter* getDevFilter(QString devName)
         if (devName != devIdString)
             goto fail;
 
-        if (m->BindToObject(0, 0, IID_IBaseFilter, reinterpret_cast<void**>(&devFilter)) != S_OK)
+        if (m->BindToObject(nullptr, nullptr, IID_IBaseFilter, reinterpret_cast<void**>(&devFilter)) != S_OK)
             goto fail;
 
     fail:

test/model/groupmessagedispatcher_test.cpp

@@ -55,7 +55,7 @@ class MockGroupQuery : public ICoreGroupQuery
 public:
     GroupId getGroupPersistentId(uint32_t groupNumber) const override
     {
-        return GroupId(0);
+        return GroupId();
     }
 
     uint32_t getGroupNumberPeers(int groupId) const override
@@ -211,7 +211,7 @@ void TestGroupMessageDispatcher::init()
     groupQuery = std::unique_ptr<MockGroupQuery>(new MockGroupQuery());
     coreIdHandler = std::unique_ptr<MockCoreIdHandler>(new MockCoreIdHandler());
     g = std::unique_ptr<Group>(
-        new Group(0, GroupId(0), "TestGroup", false, "me", *groupQuery, *coreIdHandler));
+        new Group(0, GroupId(), "TestGroup", false, "me", *groupQuery, *coreIdHandler));
     messageSender = std::unique_ptr<MockGroupMessageSender>(new MockGroupMessageSender());
     sharedProcessorParams =
         std::unique_ptr<MessageProcessor::SharedParams>(new MessageProcessor::SharedParams());