[groff] 03/20: [pic]: Fix Savannah #64488 (`lf` request usage).

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 705be31107334c00f7d963cca5f9e896b91b1022
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sat Jul 29 05:25:03 2023 -0500

    [pic]: Fix Savannah #64488 (`lf` request usage).
    
    * src/preproc/pic/troff.cpp (troff_output::set_location): Do more
      parameter validation.  Don't generate the two-argument form of the
      `lf` request if the C string holding the new file name to write isn't
      a null pointer.  Also `assert()` this since it should be an invariant.
    
    Fixes <https://savannah.gnu.org/bugs/?64488>.  Thanks to Bjarni Ingi
    Gislason for the report.
---
 ChangeLog                 | 11 +++++++++++
 src/preproc/pic/troff.cpp | 12 +++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9e697e83f..7785482a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2023-07-29  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/preproc/pic/troff.cpp (troff_output::set_location): Do
+       more parameter validation.  Don't generate the two-argument form
+       of the `lf` request if the C string holding the new file name to
+       write isn't a null pointer.  Also `assert()` this since it
+       should be an invariant.
+
+       Fixes <https://savannah.gnu.org/bugs/?64488>.  Thanks to Bjarni
+       Ingi Gislason for the report.
+
 2023-07-28  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [gxditview]: Add accelerators for "Print" action.
diff --git a/src/preproc/pic/troff.cpp b/src/preproc/pic/troff.cpp
index 3dc87a721..c66e43e2f 100644
--- a/src/preproc/pic/troff.cpp
+++ b/src/preproc/pic/troff.cpp
@@ -554,22 +554,24 @@ void troff_output::dot(const position &cent, const 
line_type &lt)
           "\\v'%.3fi+%.2fm'"
           ".\n.sp -1\n",
           c.x,
-          c.y, 
+          c.y,
           DOT_AXIS);
   }
 }
 
 void troff_output::set_location(const char *s, int n)
 {
-  if (last_filename != 0 && strcmp(s, last_filename) == 0)
-    printf(".lf %d\n", n);
-  else {
+  assert(s != 0 /* nullptr */);
+  if ((s != 0 /* nullptr */) && (last_filename != 0 /* nullptr */)
+      && strcmp(s, last_filename) == 0) {
     printf(".lf %d %s\n", n, s);
     char *lfn = strdup(s);
-    if (0 == lfn)
+    if (0 /* nullptr */ == lfn)
       fatal("memory allocation failure while copying file name");
     last_filename = lfn;
   }
+  else
+    printf(".lf %d\n", n);
 }
 
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