Ensure that passed length is non-negative

sebastinas · sebastinas · commit cb66a009bc7d · 2021-01-24T21:25:00.000+01:00
diff --git a/bpython/curtsiesfrontend/repl.py b/bpython/curtsiesfrontend/repl.py
@@ -1573,7 +1573,9 @@ def move_screen_up(current_line_start_row):
         if self.stdin.has_focus:
             cursor_row, cursor_column = divmod(
                 wcswidth(self.current_stdouterr_line)
-                + wcswidth(self.stdin.current_line, self.stdin.cursor_offset),
+                + wcswidth(
+                    self.stdin.current_line, max(0, self.stdin.cursor_offset)
+                ),
                 width,
             )
             assert cursor_row >= 0 and cursor_column >= 0, (
@@ -1600,7 +1602,7 @@ def move_screen_up(current_line_start_row):
                 (
                     wcswidth(self.current_cursor_line_without_suggestion.s)
                     - wcswidth(self.current_line)
-                    + wcswidth(self.current_line, self.cursor_offset)
+                    + wcswidth(self.current_line, max(0, self.cursor_offset))
                 )
                 + self.number_of_padding_chars_on_current_cursor_line(),
                 width,

Original file line number	Diff line number	Diff line change
`@@ -1573,7 +1573,9 @@ def move_screen_up(current_line_start_row):`
`1573`	`1573`	`if self.stdin.has_focus:`
`1574`	`1574`	`cursor_row, cursor_column = divmod(`
`1575`	`1575`	`wcswidth(self.current_stdouterr_line)`
`1576`		`- + wcswidth(self.stdin.current_line, self.stdin.cursor_offset),`
	`1576`	`+ + wcswidth(`
	`1577`	`+ self.stdin.current_line, max(0, self.stdin.cursor_offset)`
	`1578`	`+ ),`
`1577`	`1579`	`width,`
`1578`	`1580`	`)`
`1579`	`1581`	`assert cursor_row >= 0 and cursor_column >= 0, (`
`@@ -1600,7 +1602,7 @@ def move_screen_up(current_line_start_row):`
`1600`	`1602`	`(`
`1601`	`1603`	`wcswidth(self.current_cursor_line_without_suggestion.s)`
`1602`	`1604`	`- wcswidth(self.current_line)`
`1603`		`- + wcswidth(self.current_line, self.cursor_offset)`
	`1605`	`+ + wcswidth(self.current_line, max(0, self.cursor_offset))`
`1604`	`1606`	`)`
`1605`	`1607`	`+ self.number_of_padding_chars_on_current_cursor_line(),`
`1606`	`1608`	`width,`