Re: Some links to external manuals not followable in Info output

[Patrice Dumas]

On Tue, Apr 02, 2024 at 09:56:40PM +0100, Gavin Smith wrote:
> If a cross-reference appears like
> 
> @xref{,,, texi2any_api, GNU Texinfo @command{texi2any} Output Customization}.
> 
> with no first argument, then this is output in Info like
> 
> *Note (texi2any_api)::.
> 
> - with no node argument following the manual.  The Info browser (at least
> recent versions of it; I checked 6.8 and 7.1) cannot follow such links
> (I didn't check with Emacs).  However, texi2any does not warn about
> such constructs.

Here is a patch for the Info reader.  It passes the tests and in a test
with a minimum info file, followed a cross-reference as above.  But I
may have overlooked interactions with other parts of the code.

-- 
Pat

diff --git a/info/scan.c b/info/scan.c
index 4b7dfe8754..007498dabc 100644
--- a/info/scan.c
+++ b/info/scan.c
@@ -1135,7 +1135,7 @@ scan_reference_label (REFERENCE *entry, int in_index)
       len = read_quoted_string (inptr + label_len, ":", max_lines,
                                 &entry->nodename);
       canonicalize_whitespace (entry->nodename);
-      if (!len)
+      if (!len && !entry->filename)
         return 0; /* Input invalid. */
       label_len += len;
     }