[groff] 03/03: [pic]: Update input file name correctly.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 423e3c0b45a59c5476a2adc95bd38426a40456f3
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Sep 28 16:05:36 2021 +1000

    [pic]: Update input file name correctly.
    
    * src/preproc/pic/troff.cpp (troff_output::set_location): Copy the
      inbound file name argument with `strdup()` and store pointer to this
      copy in `last_filename` instead of aliasing argument.
    
      (troff_output::~troff_output): `free()` the memory allocated by
      `strdup()` in destructor.
    
    Fixes <https://savannah.gnu.org/bugs/?61206>.  Pointer assignment
    instead of a string copy was being performed, which means that after its
    initial assignment, `last_filename` always shared its value ultimately
    with the `current_filename` pointer (a libgroff symbol), so `strcmp()`
    was always being performed on identical pointers.  Problem appears to
    date back 30+ years, to the dawn of our repo history.
---
 ChangeLog                 | 18 ++++++++++++++++++
 src/preproc/pic/troff.cpp | 10 ++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c909b30..8d9aac8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2021-09-28  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [pic]: Update input file name correctly.
+
+       * src/preproc/pic/troff.cpp (troff_output::set_location): Copy
+       the inbound file name argument with `strdup()` and store pointer
+       to this copy in `last_filename` instead of aliasing argument.
+       (troff_output::~troff_output): `free()` the memory allocated by
+       `strdup()` in destructor.
+
+       Fixes <https://savannah.gnu.org/bugs/?61206>.  Pointer
+       assignment instead of a string copy was being performed, which
+       means that after its initial assignment, `last_filename` always
+       shared its value ultimately with the `current_filename` pointer
+       {a libgroff symbol}, so `strcmp()` was always being performed on
+       identical pointers.  Problem appears to date back 30+ years, to
+       the dawn of our repo history.
+
 2021-09-24  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * font/devlj4/S: Make font name consistent with file name.
diff --git a/src/preproc/pic/troff.cpp b/src/preproc/pic/troff.cpp
index 8955b30..3ccd681 100644
--- a/src/preproc/pic/troff.cpp
+++ b/src/preproc/pic/troff.cpp
@@ -1,4 +1,3 @@
-// -*- C++ -*-
 /* Copyright (C) 1989-2020 Free Software Foundation, Inc.
      Written by James Clark (jjc@jclark.com)
 
@@ -254,6 +253,7 @@ troff_output::troff_output()
 
 troff_output::~troff_output()
 {
+  free((char *)last_filename);
 }
 
 inline position troff_output::transform(const position &pos)
@@ -560,6 +560,12 @@ void troff_output::set_location(const char *s, int n)
     printf(".lf %d\n", n);
   else {
     printf(".lf %d %s\n", n, s);
-    last_filename = s;
+    last_filename = strdup(s);
   }
 }
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72: