RFC [PATCH 1/3] files: when a filename with a colon and digits exists, open that file

[Benno Schulenberg]

When the user specifies, on the command line, a filename that ends with
a colon plus digits, and that filename exists in the file system, then
open that file, instead of interpreting the digits as a line number.

Also, if the filename stripped of the colon plus digits does not exist,
then do not interpret the digits as a line number either but treat them
as part of the file name.

Before this change, the user would have to escape the colon whenever
they wanted to open a file whose name ended with a colon plus digits.
Now the user needs to escape the colon only when 'foo' exists and they
want to create, say, 'foo:24'.

Problem-was-reported-by: Ralph Corderoy <ralph@inputplus.co.uk>
  https://lists.gnu.org/archive/html/nano-devel/2024-05/msg00001.html
Mitigation-was-suggested-by: Mike Scalora <mike@scalora.org>
  https://lists.gnu.org/archive/html/nano-devel/2024-05/msg00008.html
---
 src/nano.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/nano.c b/src/nano.c
index 973054f0..0467504f 100644
--- a/src/nano.c
+++ b/src/nano.c
@@ -2495,19 +2495,24 @@ int main(int argc, char **argv)
                {
                        char *filename = argv[optind++];
                        char *colon = filename + (*filename ? 1 : 0);
+                       struct stat fileinfo;
 
                        /* Search the filename for a colon.  If the colon is 
preceded by
                         * a backslash, elide the backslash and skip the colon. 
 If there
                         * is a valid number after the colon, chop colon and 
number off.
                         * The number is later used to place the cursor on that 
line. */
+                       if (strchr(filename, ':') && stat(filename, &fileinfo) 
< 0) {
                        while ((colon = strchr(colon, ':'))) {
                                if (*(colon - 1) == '\\')
                                        memmove(colon - 1, colon, strlen(colon) 
+ 1);
-                               else if (parse_line_column(colon + 1, 
&givenline, &givencol))
+                               else if (parse_line_column(colon + 1, 
&givenline, &givencol)) {
                                        *colon = '\0';
-                               else
+                                       if (stat(filename, &fileinfo) < 0)
+                                               *colon++ = ':';
+                               } else
                                        ++colon;
                        }
+                       }
 
                        if (!open_buffer(filename, TRUE))
                                continue;
-- 
2.42.1