Remove the build-time option CLASH_DETECTION

Every platform supports it, and the runtime option `create-lockfiles'
replaces it.

* configure.ac (CLASH_DETECTION): Remove option.

* lisp/files.el (lock-buffer, unlock-buffer, file-locked-p):
Remove fallback aliases, since they are always defined now.

* src/buffer.c (Frestore_buffer_modified_p, Fkill_buffer):
* src/emacs.c (shut_down_emacs):
* src/fileio.c (Finsert_file_contents, write_region):
* src/filelock.c (top-level, syms_of_filelock):
* src/insdel.c (prepare_to_modify_buffer_1):
CLASH_DETECTION is always defined now.

* admin/CPP-DEFINES: Remove CLASH_DETECTION.

11 files changed, 25 insertions, 61 deletions

diff --git a/ChangeLog b/ChangeLog
index 627fd22a1a6..14587cfd24e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,11 @@
+2014-03-26  Glenn Morris  <rgm@gnu.org>
+
+        * configure.ac (CLASH_DETECTION): Remove option.  Every platform
+        supports it, and the runtime option `create-lockfiles' replaces it.
+
 2014-03-23  Daniel Colascione  <dancol@dancol.org>
 
-        * configure.ac: (Bug#17069) Include GFILENOTIFY objects in glib
-        check.
+        * configure.ac: (Bug#17069) Include GFILENOTIFY objects in glib check.
 
 2014-03-22  Glenn Morris  <rgm@gnu.org>
 
diff --git a/admin/CPP-DEFINES b/admin/CPP-DEFINES
index 27d87dcaa2a..8bfe2cac570 100644
--- a/admin/CPP-DEFINES
+++ b/admin/CPP-DEFINES
@@ -86,7 +86,6 @@ BROKEN_FIONREAD
 BROKEN_GET_CURRENT_DIR_NAME
 BROKEN_NON_BLOCKING_CONNECT
 BROKEN_PTY_READ_AFTER_EAGAIN
-CLASH_DETECTION
 DATA_SEG_BITS
 DEFAULT_SOUND_DEVICE
 DEVICE_SEP
diff --git a/configure.ac b/configure.ac
index f726251b219..a4a6125051c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3897,14 +3897,6 @@ if test "${opsys}" != "mingw32"; then
      in the full name stands for the login id.])
 fi
 
-dnl Every platform that uses configure supports this.
-dnl There is a create-lockfiles option you can
-dnl customize if you do not want the lock files to be written.
-dnl So it is not clear that this #define still needs to exist.
-AC_DEFINE(CLASH_DETECTION, 1, [Define if you want lock files to be written,
-  so that Emacs can tell instantly when you try to modify a file that
-  someone else has modified in his/her Emacs.])
-
 dnl Everybody supports this, except MS.
 dnl Seems like the kind of thing we should be testing for, though.
 ## Note: PTYs are broken on darwin <6.  Use at your own risk.
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index aee5738dc43..0bc53b69da0 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-26  Glenn Morris  <rgm@gnu.org>
+
+        * files.el (lock-buffer, unlock-buffer, file-locked-p):
+        Remove fallback aliases, since they are always defined now.
+
 2014-03-24  Daniel Colascione  <dancol@dancol.org>
 
         * emacs-lisp/cl-macs.el (cl--do-arglist): Use `plist-member'
diff --git a/lisp/files.el b/lisp/files.el
index a17677b564d..5883c8c348e 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -559,14 +559,6 @@ A value of nil means ignore them; anything else means query."
                  (other :tag "Query" other))
   :group 'find-file)
 
-;; Avoid losing in versions where CLASH_DETECTION is disabled.
-(or (fboundp 'lock-buffer)
-    (defalias 'lock-buffer 'ignore))
-(or (fboundp 'unlock-buffer)
-    (defalias 'unlock-buffer 'ignore))
-(or (fboundp 'file-locked-p)
-    (defalias 'file-locked-p 'ignore))
-
 (defcustom view-read-only nil
   "Non-nil means buffers visiting files read-only do so in view mode.
 In fact, this means that all read-only buffers normally have
diff --git a/src/ChangeLog b/src/ChangeLog
index 31d90663206..87c2d364b05 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2014-03-26  Glenn Morris  <rgm@gnu.org>
+
+        * buffer.c (Frestore_buffer_modified_p, Fkill_buffer):
+        * emacs.c (shut_down_emacs):
+        * fileio.c (Finsert_file_contents, write_region):
+        * filelock.c (top-level, syms_of_filelock):
+        * insdel.c (prepare_to_modify_buffer_1):
+        CLASH_DETECTION is always defined now.
+
 2014-03-25  Eli Zaretskii  <eliz@gnu.org>
 
         * w32.c (w32_delayed_load): Call DisableThreadLibraryCalls on the
diff --git a/src/buffer.c b/src/buffer.c
index daafbcef0e4..5e923d26f3f 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1,7 +1,6 @@
 /* Buffer manipulation primitives for GNU Emacs.
 
-Copyright (C) 1985-1989, 1993-1995, 1997-2014 Free Software Foundation,
-Inc.
+Copyright (C) 1985-1989, 1993-1995, 1997-2014 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -1380,7 +1379,6 @@ It is not ensured that mode lines will be updated to show the modified
 state of the current buffer.  Use with care.  */)
   (Lisp_Object flag)
 {
-#ifdef CLASH_DETECTION
   Lisp_Object fn;
 
   /* If buffer becoming modified, lock the file.
@@ -1400,7 +1398,6 @@ state of the current buffer.  Use with care.  */)
       else if (already && NILP (flag))
         unlock_file (fn);
     }
-#endif /* CLASH_DETECTION */
 
   /* Here we have a problem.  SAVE_MODIFF is used here to encode
      buffer-modified-p (as SAVE_MODIFF<MODIFF) as well as
@@ -1820,10 +1817,8 @@ cleaning up all windows currently displaying the buffer to be killed. */)
 
   /* Now there is no question: we can kill the buffer.  */
 
-#ifdef CLASH_DETECTION
   /* Unlock this buffer's file, if it is locked.  */
   unlock_buffer (b);
-#endif /* CLASH_DETECTION */
 
   GCPRO1 (buffer);
   kill_buffer_processes (buffer);
diff --git a/src/emacs.c b/src/emacs.c
index 50efcbfb60c..9d070bda51b 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1,7 +1,7 @@
 /* Fully extensible Emacs, running on Unix, intended for GNU.
 
-Copyright (C) 1985-1987, 1993-1995, 1997-1999, 2001-2014 Free Software
-Foundation, Inc.
+Copyright (C) 1985-1987, 1993-1995, 1997-1999, 2001-2014
+  Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -2032,9 +2032,7 @@ shut_down_emacs (int sig, Lisp_Object stuff)
   kill_buffer_processes (Qnil);
   Fdo_auto_save (Qt, Qnil);
 
-#ifdef CLASH_DETECTION
   unlock_all_files ();
-#endif
 
   /* There is a tendency for a SIGIO signal to arrive within exit,
      and cause a SIGHUP because the input descriptor is already closed.  */
diff --git a/src/fileio.c b/src/fileio.c
index fb0a33b39db..152b7a8a8ed 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4079,13 +4079,11 @@ by calling `format-decode', which see.  */)
 
   if (NILP (visit) && total > 0)
     {
-#ifdef CLASH_DETECTION
       if (!NILP (BVAR (current_buffer, file_truename))
           /* Make binding buffer-file-name to nil effective.  */
           && !NILP (BVAR (current_buffer, filename))
           && SAVE_MODIFF >= MODIFF)
         we_locked_file = 1;
-#endif /* CLASH_DETECTION */
       prepare_to_modify_buffer (GPT, GPT, NULL);
     }
 
@@ -4185,10 +4183,8 @@ by calling `format-decode', which see.  */)
 
   if (inserted == 0)
     {
-#ifdef CLASH_DETECTION
       if (we_locked_file)
         unlock_file (BVAR (current_buffer, file_truename));
-#endif
       Vdeactivate_mark = old_Vdeactivate_mark;
     }
   else
@@ -4337,14 +4333,12 @@ by calling `format-decode', which see.  */)
       SAVE_MODIFF = MODIFF;
       BUF_AUTOSAVE_MODIFF (current_buffer) = MODIFF;
       XSETFASTINT (BVAR (current_buffer, save_length), Z - BEG);
-#ifdef CLASH_DETECTION
       if (NILP (handler))
         {
           if (!NILP (BVAR (current_buffer, file_truename)))
             unlock_file (BVAR (current_buffer, file_truename));
           unlock_file (filename);
         }
-#endif /* CLASH_DETECTION */
       if (not_regular)
         xsignal2 (Qfile_error,
                   build_string ("not a regular file"), orig_filename);
@@ -4814,13 +4808,11 @@ write_region (Lisp_Object start, Lisp_Object end, Lisp_Object filename,
   if (!STRINGP (start) && !NILP (BVAR (current_buffer, selective_display)))
     coding.mode |= CODING_MODE_SELECTIVE_DISPLAY;
 
-#ifdef CLASH_DETECTION
   if (open_and_close_file && !auto_saving)
     {
       lock_file (lockname);
       file_locked = 1;
     }
-#endif /* CLASH_DETECTION */
 
   encoded_filename = ENCODE_FILE (filename);
   fn = SSDATA (encoded_filename);
@@ -4842,10 +4834,8 @@ write_region (Lisp_Object start, Lisp_Object end, Lisp_Object filename,
       if (desc < 0)
         {
           int open_errno = errno;
-#ifdef CLASH_DETECTION
           if (file_locked)
             unlock_file (lockname);
-#endif /* CLASH_DETECTION */
           UNGCPRO;
           report_file_errno ("Opening output file", filename, open_errno);
         }
@@ -4860,10 +4850,8 @@ write_region (Lisp_Object start, Lisp_Object end, Lisp_Object filename,
       if (ret < 0)
         {
           int lseek_errno = errno;
-#ifdef CLASH_DETECTION
           if (file_locked)
             unlock_file (lockname);
-#endif /* CLASH_DETECTION */
           UNGCPRO;
           report_file_errno ("Lseek error", filename, lseek_errno);
         }
@@ -5006,10 +4994,8 @@ write_region (Lisp_Object start, Lisp_Object end, Lisp_Object filename,
 
   unbind_to (count, Qnil);
 
-#ifdef CLASH_DETECTION
   if (file_locked)
     unlock_file (lockname);
-#endif /* CLASH_DETECTION */
 
   /* Do this before reporting IO error
      to avoid a "file has changed on disk" warning on
diff --git a/src/filelock.c b/src/filelock.c
index 5252db09104..cc5c821cadd 100644
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -55,8 +55,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "w32.h"        /* for dostounix_filename */
 #endif
 
-#ifdef CLASH_DETECTION
-
 #ifdef HAVE_UTMP_H
 #include <utmp.h>
 #endif
@@ -837,8 +835,6 @@ t if it is locked by you, else a string saying which user has locked it.  */)
   return ret;
 }
 
-#endif /* CLASH_DETECTION */
-
 void
 syms_of_filelock (void)
 {
@@ -850,9 +846,7 @@ syms_of_filelock (void)
                doc: /* Non-nil means use lockfiles to avoid editing collisions.  */);
   create_lockfiles = 1;
 
-#ifdef CLASH_DETECTION
   defsubr (&Sunlock_buffer);
   defsubr (&Slock_buffer);
   defsubr (&Sfile_locked_p);
-#endif
 }
diff --git a/src/insdel.c b/src/insdel.c
index 1c9bafd6004..5bd97f98613 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -1,6 +1,6 @@
 /* Buffer insertion/deletion and gap motion for GNU Emacs.
-   Copyright (C) 1985-1986, 1993-1995, 1997-2014 Free Software
-   Foundation, Inc.
+
+Copyright (C) 1985-1986, 1993-1995, 1997-2014 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -1829,21 +1829,11 @@ prepare_to_modify_buffer_1 (ptrdiff_t start, ptrdiff_t end,
   else
     base_buffer = current_buffer;
 
-#ifdef CLASH_DETECTION
   if (!NILP (BVAR (base_buffer, file_truename))
       /* Make binding buffer-file-name to nil effective.  */
       && !NILP (BVAR (base_buffer, filename))
       && SAVE_MODIFF >= MODIFF)
     lock_file (BVAR (base_buffer, file_truename));
-#else
-  /* At least warn if this file has changed on disk since it was visited.  */
-  if (!NILP (BVAR (base_buffer, filename))
-      && SAVE_MODIFF >= MODIFF
-      && NILP (Fverify_visited_file_modtime (Fcurrent_buffer ()))
-      && !NILP (Ffile_exists_p (BVAR (base_buffer, filename))))
-    call1 (intern ("ask-user-about-supersession-threat"),
-           BVAR (base_buffer,filename));
-#endif /* not CLASH_DETECTION */
 
   /* If `select-active-regions' is non-nil, save the region text.  */
   /* FIXME: Move this to Elisp (via before-change-functions).  */