Spreadsheet: Show the error (if any) in csv import dialog's preview

...and don't try to read from a CSV that has errors.
Fixes #5942.

Userland/Applications/Spreadsheet/ExportDialog.cpp

@@ -97,12 +97,7 @@ CSVExportDialogPage::CSVExportDialogPage(const Sheet& sheet)
 
     m_data_preview_text_editor->set_should_hide_unnecessary_scrollbars(true);
 
-    Vector<String> quote_escape_items {
+    m_quote_escape_combo_box->set_model(GUI::ItemListModel<String>::create(m_quote_escape_items));
-        // Note: Keep in sync with Writer::WriterTraits::QuoteEscape.
-        "Repeat",
-        "Backslash",
-    };
-    m_quote_escape_combo_box->set_model(GUI::ItemListModel<String>::create(quote_escape_items));
 
     // By default, use commas, double quotes with repeat, disable headers, and quote only the fields that require quoting.
     m_delimiter_comma_radio->set_checked(true);

Userland/Applications/Spreadsheet/ExportDialog.h

@@ -69,6 +69,12 @@ private:
     RefPtr<GUI::CheckBox> m_export_header_check_box;
     RefPtr<GUI::CheckBox> m_quote_all_fields_check_box;
     RefPtr<GUI::TextEditor> m_data_preview_text_editor;
+    Vector<String> m_quote_escape_items {
+        // Note: Keep in sync with Writer::WriterTraits::QuoteEscape.
+        "Repeat",
+        "Backslash",
+    };
+
     String m_temp_output_file_path;
 };
 

Userland/Applications/Spreadsheet/ImportDialog.cpp

@@ -38,6 +38,7 @@
 #include <LibGUI/ComboBox.h>
 #include <LibGUI/ItemListModel.h>
 #include <LibGUI/RadioButton.h>
+#include <LibGUI/StackWidget.h>
 #include <LibGUI/TableView.h>
 #include <LibGUI/TextBox.h>
 #include <LibGUI/Wizards/AbstractWizardPage.h>
@@ -71,13 +72,10 @@ CSVImportDialogPage::CSVImportDialogPage(StringView csv)
     m_trim_leading_field_spaces_check_box = m_page->body_widget().find_descendant_of_type_named<GUI::CheckBox>("trim_leading_field_spaces_check_box");
     m_trim_trailing_field_spaces_check_box = m_page->body_widget().find_descendant_of_type_named<GUI::CheckBox>("trim_trailing_field_spaces_check_box");
     m_data_preview_table_view = m_page->body_widget().find_descendant_of_type_named<GUI::TableView>("data_preview_table_view");
+    m_data_preview_error_label = m_page->body_widget().find_descendant_of_type_named<GUI::Label>("data_preview_error_label");
+    m_data_preview_widget = m_page->body_widget().find_descendant_of_type_named<GUI::StackWidget>("data_preview_widget");
 
-    Vector<String> quote_escape_items {
+    m_quote_escape_combo_box->set_model(GUI::ItemListModel<String>::create(m_quote_escape_items));
-        // Note: Keep in sync with Reader::ParserTraits::QuoteEscape.
-        "Repeat",
-        "Backslash",
-    };
-    m_quote_escape_combo_box->set_model(GUI::ItemListModel<String>::create(quote_escape_items));
 
     // By default, use commas, double quotes with repeat, and disable headers.
     m_delimiter_comma_radio->set_checked(true);
@@ -178,14 +176,24 @@ void CSVImportDialogPage::update_preview()
     m_previously_made_reader = make_reader();
     if (!m_previously_made_reader.has_value()) {
         m_data_preview_table_view->set_model(nullptr);
+        m_data_preview_error_label->set_text("Could not read the given file");
+        m_data_preview_widget->set_active_widget(m_data_preview_error_label);
         return;
     }
 
     auto& reader = *m_previously_made_reader;
+    if (reader.has_error()) {
+        m_data_preview_table_view->set_model(nullptr);
+        m_data_preview_error_label->set_text(String::formatted("XSV parse error:\n{}", reader.error_string()));
+        m_data_preview_widget->set_active_widget(m_data_preview_error_label);
+        return;
+    }
+
     auto headers = reader.headers();
 
     m_data_preview_table_view->set_model(
         GUI::ItemListModel<Reader::XSV::Row, Reader::XSV, Vector<String>>::create(reader, headers, min(8ul, reader.size())));
+    m_data_preview_widget->set_active_widget(m_data_preview_table_view);
     m_data_preview_table_view->update();
 }
 
@@ -207,6 +215,9 @@ Result<NonnullRefPtrVector<Sheet>, String> ImportDialog::make_and_run_for(String
             NonnullRefPtrVector<Sheet> sheets;
 
             if (reader.has_value()) {
+                if (reader.value().has_error())
+                    return String::formatted("CSV Import failed: {}", reader.value().error_string());
+
                 auto sheet = Sheet::from_xsv(reader.value(), workbook);
                 if (sheet)
                     sheets.append(sheet.release_nonnull());

Userland/Applications/Spreadsheet/ImportDialog.h

@@ -66,6 +66,13 @@ private:
     RefPtr<GUI::CheckBox> m_trim_leading_field_spaces_check_box;
     RefPtr<GUI::CheckBox> m_trim_trailing_field_spaces_check_box;
     RefPtr<GUI::TableView> m_data_preview_table_view;
+    RefPtr<GUI::Label> m_data_preview_error_label;
+    RefPtr<GUI::StackWidget> m_data_preview_widget;
+    Vector<String> m_quote_escape_items {
+        // Note: Keep in sync with Reader::ParserTraits::QuoteEscape.
+        "Repeat",
+        "Backslash",
+    };
 };
 
 struct ImportDialog {

Userland/Applications/Spreadsheet/Readers/XSV.cpp

@@ -105,6 +105,8 @@ Vector<XSV::Field> XSV::read_row(bool header_row)
 
     if (!header_row && (m_behaviours & ParserBehaviour::ReadHeaders) != ParserBehaviour::None && row.size() != m_names.size())
         set_error(ReadError::NonConformingColumnCount);
+    else if (!header_row && !has_explicit_headers() && !m_rows.is_empty() && m_rows.first().size() != row.size())
+        set_error(ReadError::NonConformingColumnCount);
 
     return row;
 }

Userland/Applications/Spreadsheet/csv_import.gml

@@ -168,9 +168,17 @@
                 margins: [10, 20, 10, 10]
             }
 
+            @GUI::StackWidget {
+                name: "data_preview_widget"
+
                 @GUI::TableView {
                     name: "data_preview_table_view"
                 }
+                @GUI::Label {
+                    name: "data_preview_error_label"
+                    word_wrap: true
+                }
+            }
         }
     }
 }