master 2337869 2/5: Pacify gcc 11.1.1 -Wanalyzer-null-argument

[Paul Eggert]

branch: master
commit 2337869fbf8b967eb53ee57f978f3751987e43dc
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Paul Eggert <eggert@cs.ucla.edu>

    Pacify gcc 11.1.1 -Wanalyzer-null-argument
    
    * lib-src/etags.c (regexp): Omit member force_explicit_name,
    since it’s always true.  All uses removed.  This lets us
    remove calls to strlen (name) where GCC isn’t smart enough
    to deduce that name must be nonnull.
    * lib-src/movemail.c (main): Fix bug that could cause
    link (tempname, NULL) to be called.
    * src/emacs.c (argmatch): Break check into two ‘if’s,
    since GCC doesn’t seem to be smart enough to check the single ‘if’.
    * src/gtkutil.c (xg_update_menu_item): Fix bug where strcmp
    could be given a NULL arg.
    * src/xfont.c (xfont_list_family): Use nonnull value for dummy
    initial value.
---
 lib-src/etags.c    | 49 +++++++++++++++++++------------------------------
 lib-src/movemail.c | 14 +++++---------
 src/emacs.c        |  4 +++-
 src/gtkutil.c      |  2 +-
 src/xfont.c        |  5 ++++-
 5 files changed, 32 insertions(+), 42 deletions(-)

diff --git a/lib-src/etags.c b/lib-src/etags.c
index c39c93d..88b49f8 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -340,7 +340,6 @@ typedef struct regexp
   struct re_pattern_buffer *pat; /* the compiled pattern */
   struct re_registers regs;    /* re registers */
   bool error_signaled;         /* already signaled for this regexp */
-  bool force_explicit_name;    /* do not allow implicit tag name */
   bool ignore_case;            /* ignore case when matching */
   bool multi_line;             /* do a multi-line match on the whole file */
 } regexp;
@@ -6910,7 +6909,6 @@ add_regex (char *regexp_pattern, language *lang)
   struct re_pattern_buffer *patbuf;
   regexp *rp;
   bool
-    force_explicit_name = true, /* do not use implicit tag names */
     ignore_case = false,       /* case is significant */
     multi_line = false,                /* matches are done one line at a time 
*/
     single_line = false;       /* dot does not match newline */
@@ -6949,7 +6947,8 @@ add_regex (char *regexp_pattern, language *lang)
       case 'N':
        if (modifiers == name)
          error ("forcing explicit tag name but no name, ignoring");
-       force_explicit_name = true;
+       /* This option has no effect and is present only for backward
+          compatibility.  */
        break;
       case 'i':
        ignore_case = true;
@@ -7004,7 +7003,6 @@ add_regex (char *regexp_pattern, language *lang)
   p_head->pat = patbuf;
   p_head->name = savestr (name);
   p_head->error_signaled = false;
-  p_head->force_explicit_name = force_explicit_name;
   p_head->ignore_case = ignore_case;
   p_head->multi_line = multi_line;
 }
@@ -7144,20 +7142,15 @@ regex_tag_multiline (void)
                name = NULL;
              else /* make a named tag */
                name = substitute (buffer, rp->name, &rp->regs);
-             if (rp->force_explicit_name)
-               {
-                 /* Force explicit tag name, if a name is there. */
-                 pfnote (name, true, buffer + linecharno,
-                         charno - linecharno + 1, lineno, linecharno);
-
-                 if (debug)
-                   fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
-                            name ? name : "(unnamed)", curfdp->taggedfname,
-                            lineno, buffer + linecharno);
-               }
-             else
-               make_tag (name, strlen (name), true, buffer + linecharno,
-                         charno - linecharno + 1, lineno, linecharno);
+
+             /* Force explicit tag name, if a name is there. */
+             pfnote (name, true, buffer + linecharno,
+                     charno - linecharno + 1, lineno, linecharno);
+
+             if (debug)
+               fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
+                        name ? name : "(unnamed)", curfdp->taggedfname,
+                        lineno, buffer + linecharno);
              break;
            }
        }
@@ -7471,18 +7464,14 @@ readline (linebuffer *lbp, FILE *stream)
                name = NULL;
              else /* make a named tag */
                name = substitute (lbp->buffer, rp->name, &rp->regs);
-             if (rp->force_explicit_name)
-               {
-                 /* Force explicit tag name, if a name is there. */
-                 pfnote (name, true, lbp->buffer, match, lineno, linecharno);
-                 if (debug)
-                   fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
-                            name ? name : "(unnamed)", curfdp->taggedfname,
-                            lineno, lbp->buffer);
-               }
-             else
-               make_tag (name, strlen (name), true,
-                         lbp->buffer, match, lineno, linecharno);
+
+             /* Force explicit tag name, if a name is there. */
+             pfnote (name, true, lbp->buffer, match, lineno, linecharno);
+
+             if (debug)
+               fprintf (stderr, "%s on %s:%"PRIdMAX": %s\n",
+                        name ? name : "(unnamed)", curfdp->taggedfname,
+                        lineno, lbp->buffer);
              break;
            }
        }
diff --git a/lib-src/movemail.c b/lib-src/movemail.c
index cfdebcc..e683da1 100644
--- a/lib-src/movemail.c
+++ b/lib-src/movemail.c
@@ -270,6 +270,7 @@ main (int argc, char **argv)
         You might also wish to verify that your system is one which
         uses lock files for this purpose.  Some systems use other methods.  */
 
+      bool lockname_unlinked = false;
       inname_len = strlen (inname);
       lockname = xmalloc (inname_len + sizeof ".lock");
       strcpy (lockname, inname);
@@ -312,15 +313,10 @@ main (int argc, char **argv)
             Five minutes should be good enough to cope with crashes
             and wedgitude, and long enough to avoid being fooled
             by time differences between machines.  */
-         if (stat (lockname, &st) >= 0)
-           {
-             time_t now = time (0);
-             if (st.st_ctime < now - 300)
-               {
-                 unlink (lockname);
-                 lockname = 0;
-               }
-           }
+         if (!lockname_unlinked
+             && stat (lockname, &st) == 0
+             && st.st_ctime < time (0) - 300)
+           lockname_unlinked = unlink (lockname) == 0 || errno == ENOENT;
        }
 
       delete_lockname = lockname;
diff --git a/src/emacs.c b/src/emacs.c
index b7982ec..866e43f 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -670,7 +670,9 @@ argmatch (char **argv, int argc, const char *sstr, const 
char *lstr,
     }
   arglen = (valptr != NULL && (p = strchr (arg, '=')) != NULL
            ? p - arg : strlen (arg));
-  if (lstr == 0 || arglen < minlen || strncmp (arg, lstr, arglen) != 0)
+  if (!lstr)
+    return 0;
+  if (arglen < minlen || strncmp (arg, lstr, arglen) != 0)
     return 0;
   else if (valptr == NULL)
     {
diff --git a/src/gtkutil.c b/src/gtkutil.c
index dee2a93..313cfc8 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -3221,7 +3221,7 @@ xg_update_menu_item (widget_value *val,
       gtk_label_set_text (wkey, utf8_key);
     }
 
-  if (! old_label || strcmp (utf8_label, old_label) != 0)
+  if (utf8_label && (! old_label || strcmp (utf8_label, old_label) != 0))
     {
       label_changed = true;
       gtk_label_set_text (wlbl, utf8_label);
diff --git a/src/xfont.c b/src/xfont.c
index 0570ee9..81d3561 100644
--- a/src/xfont.c
+++ b/src/xfont.c
@@ -596,7 +596,10 @@ xfont_list_family (struct frame *f)
   char **names;
   int num_fonts, i;
   Lisp_Object list;
-  char *last_family UNINIT;
+  char const *last_family;
+#if defined GCC_LINT || defined lint
+  last_family = "";
+#endif
   int last_len;
 
   block_input ();