Ref T304, array index fix if "7za.exe" is not available

src/blackmisc/compressutils.cpp

@@ -83,11 +83,29 @@ namespace BlackMisc
         const bool win = CBuildConfig::isRunningOnWindowsNtPlatform();
         if (!win) { return CCompressUtils::whichZip7(stdOutAndError); }
 
+        // windows check
         QStringList args;
         args << "i";
         QProcess zipProcess;
         zipProcess.start("7za.exe", args);
         const bool finished = zipProcess.waitForFinished();
+        if (stdOutAndError)
+        {
+            stdOutAndError->clear();
+            const QString pStdout = zipProcess.readAllStandardOutput();
+            const QString pStderr = zipProcess.readAllStandardError();
+            if (pStdout.isEmpty() && pStderr.isEmpty())
+            {
+                stdOutAndError->push_back("Checking 7za");
+                stdOutAndError->push_back("No 7za or failing");
+            }
+            else
+            {
+                stdOutAndError->push_back(pStdout);
+                stdOutAndError->push_back(pStderr);
+            }
+        }
+
         if (zipProcess.exitStatus() != QProcess::NormalExit) { return false; }
         if (!finished) { return false; }
         const int r = zipProcess.exitCode();

src/blackmisc/stringutils.h

@@ -108,6 +108,14 @@ namespace BlackMisc
         return s.trimmed();
     }
 
+    //! Safe "at" function, returns empty string if index does not exists
+    inline const QString &safeAt(const QStringList &stringList, int index)
+    {
+        if (stringList.size() > index) { return stringList.at(index); }
+        static const QString empty;
+        return empty;
+    }
+
     //! String with digits only
     inline bool isDigitsOnlyString(const QString &testString)
     {