#3026 missing info files not well-handled

[Leo Butler]

Maxima should handle a missing info file more gracefully:

Maxima 5.36.1 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.12
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) ? riemann

Maxima encountered a Lisp error:

 Condition in MACSYMA-TOP-LEVEL [or a callee]: INTERNAL-SIMPLE-ERROR: Cannot open the file /usr/share/doc/maxima/info/./maxima.info-1.

Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.

[Raymond Toy]

Here's a patch for this. Let me know what you think of it.

diff --git a/src/cl-info.lisp b/src/cl-info.lisp
index a120dea..c26807e 100644
--- a/src/cl-info.lisp
+++ b/src/cl-info.lisp
@@ -200,8 +200,13 @@
      (byte-offset (cadr value))
      (byte-count (caddr value))
      (text (make-string byte-count))

-     (path+filename (make-pathname :device (first dir-name) :directory (second dir-name) :name filename)))
-    (with-open-file (in path+filename :direction :input)
+     (path+filename
+      (merge-pathnames filename
+                      (make-pathname :device (first dir-name) :directory (second dir-name)))))
+    (with-open-file (in path+filename :direction :input :if-does-not-exist nil)
+      (unless in
+       (maxima::merror "Cannot find documentation for `~M': missing info file ~M~%"
+                       (car parameters) (namestring path+filename)))
       (unless (plusp byte-offset)
        ;; If byte-offset isn't positive there must be some error in
        ;; the index.  Return nil and let the caller deal with it.

[Robert Dodier]

I think this might be fixed already (with the patch shown above or one very similar); needs review.

[Leo Butler]

Oh boy! Thanks Roy. I pushed the fix in commit 7614fd0f0