Allow stopping of URL detection at newlines via url_excluded_characters

Fixes #6122

docs/changelog.rst

@@ -82,6 +82,8 @@ Detailed list of changes
 
 - X11: Fix a crash if the X server requests clipboard data after we have relinquished the clipboard (:iss:`5650`)
 
+- Allow stopping of URL detection at newlines via :opt:`url_excluded_characters` (:iss:`6122`)
+
 
 0.27.1 [2023-02-07]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

kitty/options/definition.py

@@ -469,10 +469,15 @@
     )
 
 opt('url_excluded_characters', '',
-    ctype='!url_excluded_characters',
+    option_type='python_string', ctype='!url_excluded_characters',
     long_text='''
 Additional characters to be disallowed from URLs, when detecting URLs under the
 mouse cursor. By default, all characters that are legal in URLs are allowed.
+Additionally, newlines are allowed (but stripped). This is to accommodate
+programs such as mutt that add hard line breaks even for continued lines.
+:code:`\\\\n` can be added to this option to disable this behavior. Special
+characters can be specified using backslash escapes, to specify a backslash use
+a double backslash.
 '''
     )
 

kitty/options/parse.py

@@ -3,8 +3,8 @@
 # isort: skip_file
 import typing
 from kitty.conf.utils import (
-    merge_dicts, positive_float, positive_int, to_bool, to_cmdline, to_color, to_color_or_none,
-    unit_float
+    merge_dicts, positive_float, positive_int, python_string, to_bool, to_cmdline, to_color,
+    to_color_or_none, unit_float
 )
 from kitty.options.utils import (
     action_alias, active_tab_title_template, allow_hyperlinks, bell_on_tab, box_drawing_scale,
@@ -1302,7 +1302,7 @@ def url_color(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['url_color'] = to_color(val)
 
     def url_excluded_characters(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
-        ans['url_excluded_characters'] = str(val)
+        ans['url_excluded_characters'] = python_string(val)
 
     def url_prefixes(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['url_prefixes'] = url_prefixes(val)

kitty/screen.c

@@ -2793,17 +2793,21 @@ screen_open_url(Screen *self) {
 
 // URLs {{{
 static void
-extend_url(Screen *screen, Line *line, index_type *x, index_type *y, char_type sentinel) {
+extend_url(Screen *screen, Line *line, index_type *x, index_type *y, char_type sentinel, bool newlines_allowed) {
     unsigned int count = 0;
+    bool has_newline = false;
     while(count++ < 10) {
-        if (*x != line->xnum - 1) break;
+        has_newline = !line->gpu_cells[line->xnum-1].attrs.next_char_was_wrapped;
+        if (*x != line->xnum - 1 || (!newlines_allowed && has_newline)) break;
         bool next_line_starts_with_url_chars = false;
         line = screen_visual_line(screen, *y + 2);
-        if (line) next_line_starts_with_url_chars = line_startswith_url_chars(line);
+        if (line) {
+            next_line_starts_with_url_chars = line_startswith_url_chars(line);
+            has_newline = !line->attrs.is_continued;
+            if (next_line_starts_with_url_chars && has_newline && !newlines_allowed) next_line_starts_with_url_chars = false;
+        }
         line = screen_visual_line(screen, *y + 1);
         if (!line) break;
-        // we deliberately allow non-continued lines as some programs, like
-        // mutt split URLs with newlines at line boundaries
         index_type new_x = line_url_end_at(line, 0, false, sentinel, next_line_starts_with_url_chars);
         if (!new_x && !line_startswith_url_chars(line)) break;
         *y += 1; *x = new_x;
@@ -2845,6 +2849,7 @@ screen_detect_url(Screen *screen, unsigned int x, unsigned int y) {
         return hid;
     }
     char_type sentinel = 0;
+    bool newlines_allowed = !is_excluded_from_url('\n');
     if (line) {
         url_start = line_url_start_at(line, x);
         if (url_start < line->xnum) {
@@ -2852,6 +2857,7 @@ screen_detect_url(Screen *screen, unsigned int x, unsigned int y) {
             if (y < screen->lines - 1) {
                 line = screen_visual_line(screen, y+1);
                 next_line_starts_with_url_chars = line_startswith_url_chars(line);
+                if (next_line_starts_with_url_chars && !newlines_allowed && !line->attrs.is_continued) next_line_starts_with_url_chars = false;
                 line = screen_visual_line(screen, y);
             }
             sentinel = get_url_sentinel(line, url_start);
@@ -2861,7 +2867,7 @@ screen_detect_url(Screen *screen, unsigned int x, unsigned int y) {
     }
     if (has_url) {
         index_type y_extended = y;
-        extend_url(screen, line, &url_end, &y_extended, sentinel);
+        extend_url(screen, line, &url_end, &y_extended, sentinel, newlines_allowed);
         screen_mark_url(screen, url_start, y, url_end, y_extended);
     } else {
         screen_mark_url(screen, 0, 0, 0, 0);