When the user attempts to initiate a search with a multiple selection…

… in which all selections are empty, show a message that a search region could not be constructed from the selection. Previous behavior was to become unresponsive, requiring the user to force-close Notepad++. Addresses issue #13.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Columns++ for Notepad++ -- Pre-releases
 
+## Version 0.7.5-alpha  -- October 17th, 2023
+
+* When the user attempts to initiate a search with a multiple selection in which all selections are empty, show a message that a search region could not be constructed from the selection. Previous behavior was to become unresponsive, requiring the user to force-close Notepad++. Addresses issue #13.
+
 ## Version 0.7.4-alpha  -- October 10th, 2023
 
 * The **Align numeric** command and the **Numeric aligned** option of the **Calculate...** command now take into account numbers formatted as times, based on the settings in the **Time formats** dialog.

src/Search.cpp

@@ -678,10 +678,17 @@ bool convertSelectionToSearchRegion(ColumnsPlusPlusData& data) {
         rs.extend();
         if (!rs.size()) return false;
     }
+    int n = data.sci.Selections();
+    for (int i = 0;; ++i) {
+        if (i >= n) {
+            MessageBox(data.searchData.dialog, L"Could not construct a search region from this selection.", L"Search in indicated region", MB_ICONERROR);
+            return false;
+        }
+        if (data.sci.SelectionNStart(i) < data.sci.SelectionNEnd(i)) break;
+    }
     data.sci.SetIndicatorCurrent(data.searchData.indicator);
     data.sci.IndicatorClearRange(0, data.sci.Length());
     data.sci.SetIndicatorValue(1);
-    int n = data.sci.Selections();
     for (int i = 0; i < n; ++i) data.sci.IndicatorFillRange(data.sci.SelectionNStart(i), data.sci.SelectionNEnd(i) - data.sci.SelectionNStart(i));
     if (data.searchData.autoClearSelection) data.sci.SetEmptySelection(data.sci.CurrentPos());
     return true;