fix: quote CSV fields only when required

src/app.rs

@@ -677,6 +677,10 @@ fn append_record<'a>(
             if index > 0 {
                 output.push(',');
             }
+            if !value.contains([',', '"', '\r', '\n']) {
+                output.push_str(value);
+                continue;
+            }
             output.push('"');
             for character in value.chars() {
                 if character == '"' {
@@ -755,6 +759,17 @@ fn moved_index(selected: Option<usize>, count: usize, delta: isize) -> Option<us
 mod tests {
     use super::moved_index;
 
+    #[test]
+    fn csv_quotes_only_fields_with_delimiters_quotes_or_line_breaks() {
+        let mut output = String::new();
+        super::append_record(
+            &mut output,
+            ["42", "00123", "界", "", "a,b", "a\"b", "a\rb", "a\nb"].into_iter(),
+            false,
+        );
+        assert_eq!(output, "42,00123,界,,\"a,b\",\"a\"\"b\",\"a\rb\",\"a\nb\"\r\n");
+    }
+
     #[test]
     fn rectangular_selection_copies_full_cells_and_resets_on_data_changes() -> crate::Result<()> {
         use super::{App, Focus};
@@ -799,14 +814,14 @@ mod tests {
         );
         assert_eq!(
             app.selection_text(true, false).as_deref(),
-            Some("\"b\",\"c\"\r\n\"a|b\",\"say \"\"hi\"\",界\"\r\n\"NULL\",\"<&>\\tail\"\r\n")
+            Some("b,c\r\na|b,\"say \"\"hi\"\",界\"\r\nNULL,<&>\\tail\r\n")
         );
         assert_eq!(
             app.selection_text(false, false).as_deref(),
-            Some("\"a|b\",\"say \"\"hi\"\",界\"\r\n\"NULL\",\"<&>\\tail\"\r\n")
+            Some("a|b,\"say \"\"hi\"\",界\"\r\nNULL,<&>\\tail\r\n")
         );
         assert!(app.handle_rows_command(KeyEvent::new(KeyCode::Esc, KeyModifiers::NONE)));
-        assert_eq!(app.selection_text(false, false).as_deref(), Some("\"a|b\"\r\n"));
+        assert_eq!(app.selection_text(false, false).as_deref(), Some("a|b\r\n"));
         // A prefix cancels on focus changes rather than capturing a later key.
         app.handle_rows_command(key('y'));
         assert!(!app.handle_rows_command(KeyEvent::new(KeyCode::Tab, KeyModifiers::NONE)));
@@ -814,7 +829,7 @@ mod tests {
         app.handle_rows_command(key('v'));
         app.handle_key(key('n'));
         assert!(app.selection_anchor.is_none());
-        assert_eq!(app.selection_text(false, false).as_deref(), Some("\"101\"\r\n"));
+        assert_eq!(app.selection_text(false, false).as_deref(), Some("101\r\n"));
         app.handle_rows_command(key('v'));
         app.handle_key(key('s'));
         assert!(app.selection_anchor.is_none());
@@ -824,11 +839,11 @@ mod tests {
         app.query.value = "SELECT 42 AS answer".into();
         app.execute_query();
         assert!(app.selection_anchor.is_none());
-        assert_eq!(app.selection_text(true, false).as_deref(), Some("\"answer\"\r\n\"42\"\r\n"));
+        assert_eq!(app.selection_text(true, false).as_deref(), Some("answer\r\n42\r\n"));
         app.handle_rows_command(key('v'));
         app.query.value = "SELECT missing FROM nowhere".into();
         app.execute_query();
-        assert_eq!(app.selection_text(false, false).as_deref(), Some("\"42\"\r\n"));
+        assert_eq!(app.selection_text(false, false).as_deref(), Some("42\r\n"));
         assert!(app.selection_anchor.is_some());
         app.open_relation(Some(0));
         assert!(app.selection_anchor.is_none());