encoding.csv: fix reading when there is no line ending at the end of the file (fix #22337) (#22342)

vlib/encoding/csv/csv_reader_eol_test.v

@@ -0,0 +1,34 @@
+import encoding.csv
+
+fn test_no_ending() {
+	data := 'x,y,d
+a,b
+w'
+	mut parser := csv.new_reader(data)
+	mut arr := []string{}
+	for {
+		items := parser.read() or { break }
+		arr << items.join('-')
+	}
+	dump(arr)
+	assert arr[0].str() == 'x-y-d'
+	assert arr[1].str() == 'a-b'
+	assert arr[2].str() == 'w'
+}
+
+fn test_with_ending() {
+	data := 'x,y,d
+a,b
+w
+'
+	mut parser := csv.new_reader(data)
+	mut arr := []string{}
+	for {
+		items := parser.read() or { break }
+		arr << items.join('-')
+	}
+	dump(arr)
+	assert arr[0].str() == 'x-y-d'
+	assert arr[1].str() == 'a-b'
+	assert arr[2].str() == 'w'
+}

vlib/encoding/csv/reader.v

@@ -91,7 +91,7 @@ pub fn (mut r Reader) read() ![]string {
 // }
 fn (mut r Reader) read_line() !string {
 	// last record
-	if r.row_pos == r.data.len {
+	if r.row_pos >= r.data.len {
 		return &EndOfFileError{}
 	}
 	le := if r.is_mac_pre_osx_le { '\r' } else { '\n' }
@@ -108,7 +108,7 @@ fn (mut r Reader) read_line() !string {
 			}
 		} else {
 			// No line ending on file
-			i = r.data.len - 1
+			i = r.data.len
 		}
 	}
 	mut line := r.data[r.row_pos..i]