QmakeProject: Show a better error message than just "Incompatible build"

Change-Id: I003e856dd5b222348bacd5acbdf9da4725864b35
Task-number: QTCREATORBUG-14021
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/qmakeprojectmanager/qmakebuildconfiguration.cpp

@@ -308,7 +308,7 @@ MakeStep *QmakeBuildConfiguration::makeStep() const
 }
 
 // Returns true if both are equal.
-QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportFrom(const QString &makefile)
+QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportFrom(const QString &makefile, QString *errorString)
 {
     const QLoggingCategory &logs = MakeFileParse::logging();
     qCDebug(logs) << "QMakeBuildConfiguration::compareToImport";
@@ -322,6 +322,8 @@ QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportF
     }
     if (parse.makeFileState() == MakeFileParse::CouldNotParse) {
         qCDebug(logs) << "**Makefile incompatible";
+        if (errorString)
+            *errorString = tr("Could not parse Makefile.");
         return MakefileIncompatible;
     }
 
@@ -339,6 +341,8 @@ QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportF
     if (parse.srcProFile() != qs->project()->projectFilePath().toString()) {
         qCDebug(logs) << "**Different profile used to generate the Makefile:"
                       << parse.srcProFile() << " expected profile:" << qs->project()->projectFilePath();
+        if (errorString)
+            *errorString = tr("The Makefile is for a different project.");
         return MakefileIncompatible;
     }
 
@@ -353,6 +357,8 @@ QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportF
     if (qmakeBuildConfiguration() != buildConfig) {
         qCDebug(logs) << "**Different qmake buildconfigurations buildconfiguration:"
                       << qmakeBuildConfiguration() << " Makefile:" << buildConfig;
+        if (errorString)
+            *errorString = tr("The build type has changed.");
         return MakefileIncompatible;
     }
 
@@ -396,12 +402,16 @@ QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportF
     actualArgs.sort();
     parsedArgs.sort();
     if (actualArgs != parsedArgs) {
-        qCDebug(logs) << "**Mismateched args";
+        qCDebug(logs) << "**Mismatched args";
+        if (errorString)
+            *errorString = tr("The qmake arguments have changed.");
         return MakefileIncompatible;
     }
 
     if (parse.config() != qs->deducedArguments()) {
         qCDebug(logs) << "**Mismatched config";
+        if (errorString)
+            *errorString = tr("The qmake arguments have changed.");
         return MakefileIncompatible;
     }
 
@@ -419,6 +429,8 @@ QmakeBuildConfiguration::MakefileState QmakeBuildConfiguration::compareToImportF
     }
 
     qCDebug(logs) << "**Incompatible specs";
+    if (errorString)
+        *errorString = tr("The mkspec has changed.");
     return MakefileIncompatible;
 }
 

src/plugins/qmakeprojectmanager/qmakebuildconfiguration.h

@@ -91,7 +91,7 @@ public:
     QString makefile() const;
 
     enum MakefileState { MakefileMatches, MakefileForWrongProject, MakefileIncompatible, MakefileMissing };
-    MakefileState compareToImportFrom(const QString &makefile);
+    MakefileState compareToImportFrom(const QString &makefile, QString *errorString = 0);
     static Utils::FileName extractSpecFromArguments(QString *arguments,
                                             const QString &directory, const QtSupport::BaseQtVersion *version,
                                             QStringList *outArgs = 0);

src/plugins/qmakeprojectmanager/qmakeprojectconfigwidget.cpp

@@ -213,6 +213,7 @@ void QmakeProjectConfigWidget::updateProblemLabel()
     bool incompatibleBuild = false;
     bool allGood = false;
     // we only show if we actually have a qmake and makestep
+    QString errorString;
     if (m_buildConfiguration->qmakeStep() && m_buildConfiguration->makeStep()) {
         QString makefile = m_buildConfiguration->buildDirectory().toString() + QLatin1Char('/');
         if (m_buildConfiguration->makefile().isEmpty())
@@ -220,7 +221,7 @@ void QmakeProjectConfigWidget::updateProblemLabel()
         else
             makefile.append(m_buildConfiguration->makefile());
 
-        switch (m_buildConfiguration->compareToImportFrom(makefile)) {
+        switch (m_buildConfiguration->compareToImportFrom(makefile, &errorString)) {
         case QmakeBuildConfiguration::MakefileMatches:
             allGood = true;
             break;
@@ -274,8 +275,9 @@ void QmakeProjectConfigWidget::updateProblemLabel()
                         .arg(m_buildConfiguration->buildDirectory().toUserOutput()));
         return;
     } else if (incompatibleBuild) {
-        setProblemLabel(tr("An incompatible build exists in %1, which will be overwritten.",
-                           "%1 build directory")
+        setProblemLabel(tr("%1 The build in %2 will be overwritten.",
+                           "%1 error message, %2 build directory")
+                        .arg(errorString)
                         .arg(m_buildConfiguration->buildDirectory().toUserOutput()));
         return;
     }