Re: Emacs 26 MacOS bugs

[Paul Eggert <eggert@cs.ucla.edu>]

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On 02/06/2018 09:30 AM, Noam Postavsky wrote:
> on w32 I get an assertion failure, patch attached.

On Fedora 27 x86-64 I get a crash when running 'emacs 
--no-build-details'. There are several places in the Emacs code that 
crash when Fsystem_name returns a non-string. Proposed patch attached.


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From c7602b4e9e074eb8d0fd701d094f1c244713a70f Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 6 Feb 2018 15:25:45 -0800
Subject: [PATCH] Fix crashes when run with --no-build-details
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* src/xrdb.c (get_environ_db):
* src/xterm.c (same_x_server, x_term_init):
Don’t assume Fsystem_name returns a string.
---
 src/xrdb.c  | 19 +++++++++++--------
 src/xterm.c | 16 +++++++++++-----
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/xrdb.c b/src/xrdb.c
index b55c0f9011..836c147947 100644
--- a/src/xrdb.c
+++ b/src/xrdb.c
@@ -376,15 +376,18 @@ get_environ_db (void)
 
   if (!p)
     {
-      /* Use ~/.Xdefaults-HOSTNAME.  */
-      char *home = gethomedir ();
-      ptrdiff_t homelen = strlen (home);
       Lisp_Object system_name = Fsystem_name ();
-      ptrdiff_t filenamesize = (homelen + sizeof xdefaults
-				+ 1 + SBYTES (system_name));
-      p = filename = xrealloc (home, filenamesize);
-      lispstpcpy (stpcpy (stpcpy (filename + homelen, xdefaults), "-"),
-		  system_name);
+      if (STRINGP (system_name))
+	{
+	  /* Use ~/.Xdefaults-HOSTNAME.  */
+	  char *home = gethomedir ();
+	  ptrdiff_t homelen = strlen (home);
+	  ptrdiff_t filenamesize = (homelen + sizeof xdefaults
+				    + 1 + SBYTES (system_name));
+	  p = filename = xrealloc (home, filenamesize);
+	  lispstpcpy (stpcpy (stpcpy (filename + homelen, xdefaults), "-"),
+		      system_name);
+	}
     }
 
   db = XrmGetFileDatabase (p);
diff --git a/src/xterm.c b/src/xterm.c
index 364a8a8db0..b10664dda9 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -12150,6 +12150,8 @@ same_x_server (const char *name1, const char *name2)
 {
   bool seen_colon = false;
   Lisp_Object sysname = Fsystem_name ();
+  if (! STRINGP (sysname))
+    sysname = empty_unibyte_string;
   const char *system_name = SSDATA (sysname);
   ptrdiff_t system_name_length = SBYTES (sysname);
   ptrdiff_t length_until_period = 0;
@@ -12572,15 +12574,19 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
 #endif
 
   Lisp_Object system_name = Fsystem_name ();
-  ptrdiff_t nbytes;
-  if (INT_ADD_WRAPV (SBYTES (Vinvocation_name), SBYTES (system_name) + 2,
-		     &nbytes))
+
+  ptrdiff_t nbytes = SBYTES (Vinvocation_name) + 1;
+  if (STRINGP (system_name)
+      && INT_ADD_WRAPV (nbytes, SBYTES (system_name) + 1, &nbytes))
     memory_full (SIZE_MAX);
   dpyinfo->x_id = ++x_display_id;
   dpyinfo->x_id_name = xmalloc (nbytes);
   char *nametail = lispstpcpy (dpyinfo->x_id_name, Vinvocation_name);
-  *nametail++ = '@';
-  lispstpcpy (nametail, system_name);
+  if (STRINGP (system_name))
+    {
+      *nametail++ = '@';
+      lispstpcpy (nametail, system_name);
+    }
 
   /* Figure out which modifier bits mean what.  */
   x_find_modifier_meanings (dpyinfo);
-- 
2.14.3