Catch C++ exceptions by const reference

Fixes #2277

application/MultiMC.cpp

@@ -174,7 +174,7 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
 		{
 			args = parser.parse(arguments());
 		}
-		catch (ParsingError e)
+		catch (const ParsingError &e)
 		{
 			std::cerr << "CommandLineError: " << e.what() << std::endl;
 			std::cerr << "Try '%1 -h' to get help on MultiMC's command line parameters."

application/UpdateController.cpp

@@ -331,7 +331,7 @@ void UpdateController::installUpdates()
 					break;
 				}
 			}
-			catch(Exception e)
+			catch (const Exception &e)
 			{
 				qWarning() << "Couldn't read the" << liveCheckFile << "file!";
 				startFailed = true;

application/dialogs/ExportInstanceDialog.cpp

@@ -479,7 +479,7 @@ void ExportInstanceDialog::savePackIgnore()
 	{
 		FS::write(filename, data);
 	}
-	catch (Exception & e)
+	catch (const Exception &e)
 	{
 		qWarning() << e.cause();
 	}

application/dialogs/UpdateDialog.cpp

@@ -135,7 +135,7 @@ QString reprocessCommits(QByteArray json)
 		result += QObject::tr("<p>You can <a href=\"%1\">look at the changes on github</a>.</p>").arg(diff_url);
 		return result;
 	}
-	catch (JSONValidationError & e)
+	catch (const JSONValidationError &e)
 	{
 		qWarning() << "Got an unparseable commit log from github:" << e.what();
 		qDebug() << json;

application/pages/instance/ServersPage.cpp

@@ -109,7 +109,7 @@ static std::unique_ptr <nbt::tag_compound> parseServersDat(const QString& filena
 
 		return std::move(pair.second);
 	}
-	catch(...)
+	catch (...)
 	{
 		return nullptr;
 	}
@@ -125,7 +125,7 @@ static bool serializeServerDat(const QString& filename, nbt::tag_compound * leve
 		FS::write(filename, val);
 		return true;
 	}
-	catch(...)
+	catch (...)
 	{
 		return false;
 	}

application/pages/instance/VersionPage.cpp

@@ -200,7 +200,7 @@ bool VersionPage::reloadComponentList()
 		m_profile->reload(Net::Mode::Online);
 		return true;
 	}
-	catch (Exception &e)
+	catch (const Exception &e)
 	{
 		QMessageBox::critical(this, tr("Error"), e.cause());
 		return false;
@@ -269,7 +269,7 @@ void VersionPage::on_moveUpBtn_clicked()
 	{
 		m_profile->move(currentRow(), ComponentList::MoveUp);
 	}
-	catch (Exception &e)
+	catch (const Exception &e)
 	{
 		QMessageBox::critical(this, tr("Error"), e.cause());
 	}
@@ -282,7 +282,7 @@ void VersionPage::on_moveDownBtn_clicked()
 	{
 		m_profile->move(currentRow(), ComponentList::MoveDown);
 	}
-	catch (Exception &e)
+	catch (const Exception &e)
 	{
 		QMessageBox::critical(this, tr("Error"), e.cause());
 	}

application/themes/CustomTheme.cpp

@@ -66,7 +66,7 @@ static bool readThemeJson(const QString &path, QPalette &palette, double &fadeAm
 			fadeAmount = Json::ensureDouble(colorsRoot, "fadeAmount", 0.5, "fade amount");
 
 		}
-		catch(Exception e)
+		catch (const Exception &e)
 		{
 			qWarning() << "Couldn't load theme json: " << e.cause();
 			return false;
@@ -117,7 +117,7 @@ static bool writeThemeJson(const QString &path, const QPalette &palette, double
 		Json::write(rootObj, path);
 		return true;
 	}
-	catch (Exception e)
+	catch (const Exception &e)
 	{
 		qWarning() << "Failed to write theme json to" << path;
 		return false;
@@ -171,7 +171,7 @@ CustomTheme::CustomTheme(ITheme* baseTheme, QString folder)
 			// TODO: validate css?
 			m_styleSheet = QString::fromUtf8(FS::read(cssFilePath));
 		}
-		catch(Exception e)
+		catch (const Exception &e)
 		{
 			qWarning() << "Couldn't load css:" << e.cause() << "from" << cssFilePath;
 			m_styleSheet = baseTheme->appStyleSheet();
@@ -185,7 +185,7 @@ CustomTheme::CustomTheme(ITheme* baseTheme, QString folder)
 		{
 			FS::write(cssFilePath, m_styleSheet.toUtf8());
 		}
-		catch(Exception e)
+		catch (const Exception &e)
 		{
 			qWarning() << "Couldn't write css:" << e.cause() << "to" << cssFilePath;
 		}