patch 8.0.1736: check for C99 features is incomplete

Problem:    Check for C99 features is incomplete.
Solution:   Use AC_PROG_CC_C99 and when C99 isn't fully supported check the
            features we need. (James McCoy, closes #2820)

runtime/doc/develop.txt

@@ -1,4 +1,4 @@
-*develop.txt*   For Vim version 8.0.  Last change: 2017 Jul 31
+*develop.txt*   For Vim version 8.0.  Last change: 2018 Apr 17
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -185,9 +185,40 @@ The basic steps to make changes to the code:
 C COMPILER						*style-compiler*
 
 The minimal C compiler version supported is C89, also known as ANSI C.
-Later standards don't add much and C89 is the widest supported.
+Later standards, such as C99, are not widely supported, or at least not 100%
+supported.  Therefore we use only some of the C99 features and disallow some
+(at least for now).
 
-One restriction that this implies: no // comments, only /* comments */.
+Please don't make changes everywhere to use the C99 features, it causes merge
+problems for existing patches.  Only use them for new and changed code.
+
+Comments ~
+
+Traditionally Vim uses /* comments */.  We intend to keep it that way,
+especially for file and function headers.  For new code or lines of code that
+change, it is allowed to use // comments.  Especially when it comes after
+code:
+	int some_var;  // single line comment useful here
+
+Enums ~
+
+The last item in an enum may have a trailing comma.  C89 didn't allow this.
+
+Types ~
+
+"long long" is allowed and can be expected to be 64 bits.  Use %lld in printf
+formats.  Also "long long unsigned" with %llu.
+
+Not to be used ~
+
+These C99 features are not to be used, because not enough compilers support
+them:
+- Declaration after Statements (MSVC 2012 does not support it).  All
+  declarations need to be at the start of the block.
+- Variable length arrays (even in C11 this is an optional feature).
+- _Bool and _Complex types.
+- "inline" (it's hardly ever needed, let the optimizer do its work)
+- flexible array members: Not supported by HP-UX C compiler (John Marriott)
 
 
 USE OF COMMON FUNCTIONS					*style-functions*

src/auto/configure

@@ -3454,81 +3454,167 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
-   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
-$as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
-if ${ac_cv_prog_cc_c89+:} false; then :
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C99" >&5
+$as_echo_n "checking for $CC option to accept ISO C99... " >&6; }
+if ${ac_cv_prog_cc_c99+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  ac_cv_prog_cc_c89=no
+  ac_cv_prog_cc_c99=no
 ac_save_CC=$CC
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <stdarg.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <wchar.h>
 #include <stdio.h>
-struct stat;
-/* Most of the following tests are stolen from RCS 5.7's src/conf.sh.  */
-struct buf { int x; };
-FILE * (*rcsopen) (struct buf *, struct stat *, int);
-static char *e (p, i)
-     char **p;
-     int i;
+
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
+#define debug(...) fprintf (stderr, __VA_ARGS__)
+#define showlist(...) puts (#__VA_ARGS__)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
+static void
+test_varargs_macros (void)
 {
-  return p[i];
-}
-static char *f (char * (*g) (char **, int), char **p, ...)
-{
-  char *s;
-  va_list v;
-  va_start (v,p);
-  s = g (p, va_arg (v,int));
-  va_end (v);
-  return s;
+  int x = 1234;
+  int y = 5678;
+  debug ("Flag");
+  debug ("X = %d\n", x);
+  showlist (The first, second, and third items.);
+  report (x>y, "x is %d but y is %d", x, y);
 }
 
-/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
-   function prototypes and stuff, but not '\xHH' hex character constants.
-   These don't provoke an error unfortunately, instead are silently treated
-   as 'x'.  The following induces an error, until -std is added to get
-   proper ANSI mode.  Curiously '\x00'!='x' always comes out true, for an
-   array size at least.  It's necessary to write '\x00'==0 to get something
-   that's true only with -std.  */
-int osf4_cc_array ['\x00' == 0 ? 1 : -1];
+// Check long long types.
+#define BIG64 18446744073709551615ull
+#define BIG32 4294967295ul
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
+#if !BIG_OK
+  your preprocessor is broken;
+#endif
+#if BIG_OK
+#else
+  your preprocessor is broken;
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
 
-/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
-   inside strings and character constants.  */
-#define FOO(x) 'x'
-int xlc6_cc_array[FOO(a) == 'x' ? 1 : -1];
+struct incomplete_array
+{
+  int datasize;
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // See if C++-style comments work.
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\0'; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static void
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str;
+  int number;
+  float fnumber;
+
+  while (*format)
+    {
+      switch (*format++)
+	{
+	case 's': // string
+	  str = va_arg (args_copy, const char *);
+	  break;
+	case 'd': // int
+	  number = va_arg (args_copy, int);
+	  break;
+	case 'f': // float
+	  fnumber = va_arg (args_copy, double);
+	  break;
+	default:
+	  break;
+	}
+    }
+  va_end (args_copy);
+  va_end (args);
+}
 
-int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};
-int pairnames (int, char **, FILE *(*)(struct buf *, struct stat *, int), int, int);
-int argc;
-char **argv;
 int
 main ()
 {
-return f (e, argv, 0) != argv[0]  ||  f (e, argv, 1) != argv[1];
+
+  // Check bool.
+  _Bool success = false;
+
+  // Check restrict.
+  if (test_restrict ("String literal") == 0)
+    success = true;
+  char *restrict newvar = "Another string";
+
+  // Check varargs.
+  test_varargs ("s, d' f .", "string", 65, 34.234);
+  test_varargs_macros ();
+
+  // Check flexible array members.
+  struct incomplete_array *ia =
+    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
+  ia->datasize = 10;
+  for (int i = 0; i < ia->datasize; ++i)
+    ia->data[i] = i * 1.234;
+
+  // Check named initializers.
+  struct named_init ni = {
+    .number = 34,
+    .name = L"Test wide string",
+    .average = 543.34343,
+  };
+
+  ni.number = 58;
+
+  int dynamic_array[ni.number];
+  dynamic_array[ni.number - 1] = 543;
+
+  // work around unused variable warnings
+  return (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x'
+	  || dynamic_array[ni.number - 1] != 543);
+
   ;
   return 0;
 }
 _ACEOF
-for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std \
-	-Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+for ac_arg in '' -std=gnu99 -std=c99 -c99 -AC99 -D_STDC_C99= -qlanglvl=extc99
 do
   CC="$ac_save_CC $ac_arg"
   if ac_fn_c_try_compile "$LINENO"; then :
-  ac_cv_prog_cc_c89=$ac_arg
+  ac_cv_prog_cc_c99=$ac_arg
 fi
 rm -f core conftest.err conftest.$ac_objext
-  test "x$ac_cv_prog_cc_c89" != "xno" && break
+  test "x$ac_cv_prog_cc_c99" != "xno" && break
 done
 rm -f conftest.$ac_ext
 CC=$ac_save_CC
 
 fi
 # AC_CACHE_VAL
-case "x$ac_cv_prog_cc_c89" in
+case "x$ac_cv_prog_cc_c99" in
   x)
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
 $as_echo "none needed" >&6; } ;;
@@ -3536,11 +3622,11 @@ $as_echo "none needed" >&6; } ;;
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
 $as_echo "unsupported" >&6; } ;;
   *)
-    CC="$CC $ac_cv_prog_cc_c89"
-    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
-$as_echo "$ac_cv_prog_cc_c89" >&6; } ;;
+    CC="$CC $ac_cv_prog_cc_c99"
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c99" >&5
+$as_echo "$ac_cv_prog_cc_c99" >&6; } ;;
 esac
-if test "x$ac_cv_prog_cc_c89" != xno; then :
+if test "x$ac_cv_prog_cc_c99" != xno; then :
 
 fi
 
@@ -4179,6 +4265,194 @@ $as_echo "#define HAVE_SYS_WAIT_H 1" >>confdefs.h
 fi
 
 
+if test x"$ac_cv_prog_cc_c99" != xno; then
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for unsigned long long int" >&5
+$as_echo_n "checking for unsigned long long int... " >&6; }
+if ${ac_cv_type_unsigned_long_long_int+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_type_unsigned_long_long_int=yes
+     if test "x${ac_cv_prog_cc_c99-no}" = xno; then
+       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+  /* For now, do not test the preprocessor; as of 2007 there are too many
+	 implementations with broken preprocessors.  Perhaps this can
+	 be revisited in 2012.  In the meantime, code should not expect
+	 #if to work with literals wider than 32 bits.  */
+      /* Test literals.  */
+      long long int ll = 9223372036854775807ll;
+      long long int nll = -9223372036854775807LL;
+      unsigned long long int ull = 18446744073709551615ULL;
+      /* Test constant expressions.   */
+      typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
+		     ? 1 : -1)];
+      typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
+		     ? 1 : -1)];
+      int i = 63;
+int
+main ()
+{
+/* Test availability of runtime routines for shift and division.  */
+      long long int llmax = 9223372036854775807ll;
+      unsigned long long int ullmax = 18446744073709551615ull;
+      return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
+	      | (llmax / ll) | (llmax % ll)
+	      | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
+	      | (ullmax / ull) | (ullmax % ull));
+  ;
+  return 0;
+}
+
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+
+else
+  ac_cv_type_unsigned_long_long_int=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+     fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_type_unsigned_long_long_int" >&5
+$as_echo "$ac_cv_type_unsigned_long_long_int" >&6; }
+  if test $ac_cv_type_unsigned_long_long_int = yes; then
+
+$as_echo "#define HAVE_UNSIGNED_LONG_LONG_INT 1" >>confdefs.h
+
+  fi
+
+
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for long long int" >&5
+$as_echo_n "checking for long long int... " >&6; }
+if ${ac_cv_type_long_long_int+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_type_long_long_int=yes
+      if test "x${ac_cv_prog_cc_c99-no}" = xno; then
+	ac_cv_type_long_long_int=$ac_cv_type_unsigned_long_long_int
+	if test $ac_cv_type_long_long_int = yes; then
+	  	  	  	  if test "$cross_compiling" = yes; then :
+  :
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <limits.h>
+		 #ifndef LLONG_MAX
+		 # define HALF \
+			  (1LL << (sizeof (long long int) * CHAR_BIT - 2))
+		 # define LLONG_MAX (HALF - 1 + HALF)
+		 #endif
+int
+main ()
+{
+long long int n = 1;
+		 int i;
+		 for (i = 0; ; i++)
+		   {
+		     long long int m = n << i;
+		     if (m >> i != n)
+		       return 1;
+		     if (LLONG_MAX / 2 < m)
+		       break;
+		   }
+		 return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+
+else
+  ac_cv_type_long_long_int=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+	fi
+      fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_type_long_long_int" >&5
+$as_echo "$ac_cv_type_long_long_int" >&6; }
+  if test $ac_cv_type_long_long_int = yes; then
+
+$as_echo "#define HAVE_LONG_LONG_INT 1" >>confdefs.h
+
+  fi
+
+  if test "$ac_cv_type_long_long_int" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support long long int
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler supports trailing commas" >&5
+$as_echo_n "checking if the compiler supports trailing commas... " >&6; }
+  trailing_commas=no
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+    enum {
+      one,
+    };
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }; trailing_commas=yes
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  if test "$trailing_commas" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support trailing comma in enum
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking if the compiler supports C++ comments" >&5
+$as_echo_n "checking if the compiler supports C++ comments... " >&6; }
+  slash_comments=no
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+// C++ comments?
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }; slash_comments=yes
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  if test "$slash_comments" = no; then
+    { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "Compiler does not support C++ comments
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+fi
+
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking --enable-fail-if-missing argument" >&5
 $as_echo_n "checking --enable-fail-if-missing argument... " >&6; }

src/buffer.c

@@ -417,6 +417,8 @@ buf_hashtab_remove(buf_T *buf)
 	hash_remove(&buf_hashtab, hi);
 }
 
+static char *e_buflocked = N_("E937: Attempt to delete a buffer that is in use");
+
 /*
  * Close the link to a buffer.
  * "action" is used when there is no longer a window for the buffer.
@@ -476,8 +478,15 @@ close_buffer(
 	if (term_job_running(buf->b_term))
 	{
 	    if (wipe_buf || unload_buf)
+	    {
+		if (buf->b_locked)
+		{
+		    EMSG(_(e_buflocked));
+		    return;
+		}
 		/* Wiping out or unloading a terminal buffer kills the job. */
 		free_terminal(buf);
+	    }
 	    else
 	    {
 		/* The job keeps running, hide the buffer. */
@@ -499,7 +508,7 @@ close_buffer(
      * halfway a command that relies on it). Unloading is allowed. */
     if (buf->b_locked > 0 && (del_buf || wipe_buf))
     {
-	EMSG(_("E937: Attempt to delete a buffer that is in use"));
+	EMSG(_(e_buflocked));
 	return;
     }
 
@@ -1356,6 +1365,12 @@ do_buffer(
 	int	forward;
 	bufref_T bufref;
 
+	if (buf->b_locked)
+	{
+	    EMSG(_(e_buflocked));
+	    return FAIL;
+	}
+
 	set_bufref(&bufref, buf);
 
 	/* When unloading or deleting a buffer that's already unloaded and

src/configure.ac

@@ -11,7 +11,7 @@ AC_DEFINE(UNIX)
 AC_PROG_MAKE_SET
 
 dnl Checks for programs.
-AC_PROG_CC_C89		dnl required by almost everything
+AC_PROG_CC_C99		dnl required by almost everything
 AC_PROG_CPP		dnl required by header file checks
 AC_PROGRAM_EGREP	dnl required by AC_EGREP_CPP
 AC_PROG_FGREP		dnl finds working grep -F
@@ -29,6 +29,39 @@ dnl in autoconf needs it, where it uses STDC_HEADERS.
 AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
 
+dnl Check that the C99 features that Vim uses are supported:
+if test x"$ac_cv_prog_cc_c99" != xno; then
+  dnl If the compiler doesn't explicitly support C99, then check
+  dnl for the specific features Vim uses
+
+  AC_TYPE_LONG_LONG_INT
+  if test "$ac_cv_type_long_long_int" = no; then
+    AC_MSG_FAILURE([Compiler does not support long long int])
+  fi
+
+  AC_MSG_CHECKING([if the compiler supports trailing commas])
+  trailing_commas=no
+  AC_TRY_COMPILE([], [
+    enum {
+      one,
+    };],
+    [AC_MSG_RESULT(yes); trailing_commas=yes],
+    [AC_MSG_RESULT(no)])
+  if test "$trailing_commas" = no; then
+    AC_MSG_FAILURE([Compiler does not support trailing comma in enum])
+  fi
+
+  AC_MSG_CHECKING([if the compiler supports C++ comments])
+  slash_comments=no
+  AC_TRY_COMPILE([],
+    [// C++ comments?],
+    [AC_MSG_RESULT(yes); slash_comments=yes],
+    [AC_MSG_RESULT(no)])
+  if test "$slash_comments" = no; then
+    AC_MSG_FAILURE([Compiler does not support C++ comments])
+  fi
+fi
+
 dnl Check for the flag that fails if stuff are missing.
 
 AC_MSG_CHECKING(--enable-fail-if-missing argument)

src/edit.c

@@ -3656,7 +3656,9 @@ ins_compl_set_original_text(char_u *str)
 {
     char_u	*p;
 
-    /* Replace the original text entry. */
+    /* Replace the original text entry.
+     * The ORIGINAL_TEXT flag is either at the first item or might possibly be
+     * at the last item for backward completion */
     if (compl_first_match->cp_flags & ORIGINAL_TEXT)	/* safety check */
     {
 	p = vim_strsave(str);
@@ -3666,6 +3668,16 @@ ins_compl_set_original_text(char_u *str)
 	    compl_first_match->cp_str = p;
 	}
     }
+    else if (compl_first_match->cp_prev != NULL
+	    && (compl_first_match->cp_prev->cp_flags & ORIGINAL_TEXT))
+    {
+       p = vim_strsave(str);
+       if (p != NULL)
+       {
+           vim_free(compl_first_match->cp_prev->cp_str);
+           compl_first_match->cp_prev->cp_str = p;
+       }
+    }
 }
 
 /*

src/ex_cmds2.c

@@ -3821,10 +3821,30 @@ static int APP_BOTH;
     static void
 add_pack_plugin(char_u *fname, void *cookie)
 {
-    if (cookie != &APP_LOAD && strstr((char *)p_rtp, (char *)fname) == NULL)
+    if (cookie != &APP_LOAD)
+    {
+	char_u	*buf = alloc(MAXPATHL);
+	char_u	*p;
+	int	found = FALSE;
+
+	if (buf == NULL)
+	    return;
+	p = p_rtp;
+	while (*p != NUL)
+	{
+	    copy_option_part(&p, buf, MAXPATHL, ",");
+	    if (pathcmp((char *)buf, (char *)fname, -1) == 0)
+	    {
+		found = TRUE;
+		break;
+	    }
+	}
+	vim_free(buf);
+	if (!found)
 	    /* directory is not yet in 'runtimepath', add it */
 	    if (add_pack_dir_to_rtp(fname) == FAIL)
 		return;
+    }
 
     if (cookie != &APP_ADD_DIR)
 	load_pack_plugin(fname);

src/getchar.c

@@ -40,9 +40,9 @@
 
 #define MINIMAL_SIZE 20			/* minimal size for b_str */
 
-static buffheader_T redobuff = {NULL, NULL, 0, 0};
-static buffheader_T old_redobuff = {NULL, NULL, 0, 0};
-static buffheader_T recordbuff = {NULL, NULL, 0, 0};
+static buffheader_T redobuff = {{NULL, {NUL}}, NULL, 0, 0};
+static buffheader_T old_redobuff = {{NULL, {NUL}}, NULL, 0, 0};
+static buffheader_T recordbuff = {{NULL, {NUL}}, NULL, 0, 0};
 
 static int typeahead_char = 0;		/* typeahead char that's not flushed */
 
@@ -138,13 +138,12 @@ free_buff(buffheader_T *buf)
 {
     buffblock_T	*p, *np;
 
-    for (p = buf->bh_first; p != NULL; p = np)
+    for (p = buf->bh_first.b_next; p != NULL; p = np)
     {
 	np = p->b_next;
 	vim_free(p);
     }
-    buf->bh_first = NULL;
-    buf->bh_curr = NULL;
+    buf->bh_first.b_next = NULL;
 }
 
 /*
@@ -163,13 +162,13 @@ get_buffcont(
     buffblock_T *bp;
 
     /* compute the total length of the string */
-    for (bp = buffer->bh_first; bp != NULL; bp = bp->b_next)
+    for (bp = buffer->bh_first.b_next; bp != NULL; bp = bp->b_next)
 	count += (long_u)STRLEN(bp->b_str);
 
     if ((count || dozero) && (p = lalloc(count + 1, TRUE)) != NULL)
     {
 	p2 = p;
-	for (bp = buffer->bh_first; bp != NULL; bp = bp->b_next)
+	for (bp = buffer->bh_first.b_next; bp != NULL; bp = bp->b_next)
 	    for (str = bp->b_str; *str; )
 		*p2++ = *str++;
 	*p2 = NUL;
@@ -240,10 +239,10 @@ add_buff(
     if (slen == 0)				/* don't add empty strings */
 	return;
 
-    if (buf->bh_first == NULL)	/* first add to list */
+    if (buf->bh_first.b_next == NULL)	/* first add to list */
     {
 	buf->bh_space = 0;
-	buf->bh_curr = NULL;
+	buf->bh_curr = &(buf->bh_first);
     }
     else if (buf->bh_curr == NULL)	/* buffer has already been read */
     {
@@ -251,9 +250,9 @@ add_buff(
 	return;
     }
     else if (buf->bh_index != 0)
-	mch_memmove(buf->bh_first->b_str,
-		    buf->bh_first->b_str + buf->bh_index,
-		    STRLEN(buf->bh_first->b_str + buf->bh_index) + 1);
+	mch_memmove(buf->bh_first.b_next->b_str,
+		    buf->bh_first.b_next->b_str + buf->bh_index,
+		    STRLEN(buf->bh_first.b_next->b_str + buf->bh_index) + 1);
     buf->bh_index = 0;
 
     if (buf->bh_space >= (int)slen)
@@ -268,26 +267,17 @@ add_buff(
 	    len = MINIMAL_SIZE;
 	else
 	    len = slen;
-	p = (buffblock_T *)lalloc((long_u)(sizeof(buffblock_T) + len + 1),
+	p = (buffblock_T *)lalloc((long_u)(sizeof(buffblock_T) + len),
 									TRUE);
 	if (p == NULL)
 	    return; /* no space, just forget it */
 	buf->bh_space = (int)(len - slen);
 	vim_strncpy(p->b_str, s, (size_t)slen);
 
-	if (buf->bh_curr == NULL)
-	{
-	    p->b_next = NULL;
-	    buf->bh_first = p;
-	    buf->bh_curr = p;
-	}
-	else
-	{
 	p->b_next = buf->bh_curr->b_next;
 	buf->bh_curr->b_next = p;
 	buf->bh_curr = p;
     }
-    }
     return;
 }
 
@@ -358,10 +348,10 @@ add_char_buff(buffheader_T *buf, int c)
 }
 
 /* First read ahead buffer. Used for translated commands. */
-static buffheader_T readbuf1 = {NULL, NULL, 0, 0};
+static buffheader_T readbuf1 = {{NULL, {NUL}}, NULL, 0, 0};
 
 /* Second read ahead buffer. Used for redo. */
-static buffheader_T readbuf2 = {NULL, NULL, 0, 0};
+static buffheader_T readbuf2 = {{NULL, {NUL}}, NULL, 0, 0};
 
 /*
  * Get one byte from the read buffers.  Use readbuf1 one first, use readbuf2
@@ -386,17 +376,17 @@ read_readbuf(buffheader_T *buf, int advance)
     char_u	c;
     buffblock_T	*curr;
 
-    if (buf->bh_first == NULL)  /* buffer is empty */
+    if (buf->bh_first.b_next == NULL)  /* buffer is empty */
 	return NUL;
 
-    curr = buf->bh_first;
+    curr = buf->bh_first.b_next;
     c = curr->b_str[buf->bh_index];
 
     if (advance)
     {
 	if (curr->b_str[++buf->bh_index] == NUL)
 	{
-	    buf->bh_first = curr->b_next;
+	    buf->bh_first.b_next = curr->b_next;
 	    vim_free(curr);
 	    buf->bh_index = 0;
 	}
@@ -410,14 +400,14 @@ read_readbuf(buffheader_T *buf, int advance)
     static void
 start_stuff(void)
 {
-    if (readbuf1.bh_first != NULL)
+    if (readbuf1.bh_first.b_next != NULL)
     {
-	readbuf1.bh_curr = readbuf1.bh_first;
+	readbuf1.bh_curr = &(readbuf1.bh_first);
 	readbuf1.bh_space = 0;
     }
-    if (readbuf2.bh_first != NULL)
+    if (readbuf2.bh_first.b_next != NULL)
     {
-	readbuf2.bh_curr = readbuf2.bh_first;
+	readbuf2.bh_curr = &(readbuf2.bh_first);
 	readbuf2.bh_space = 0;
     }
 }
@@ -428,8 +418,8 @@ start_stuff(void)
     int
 stuff_empty(void)
 {
-    return (readbuf1.bh_first == NULL
-	 && readbuf2.bh_first == NULL);
+    return (readbuf1.bh_first.b_next == NULL
+	 && readbuf2.bh_first.b_next == NULL);
 }
 
 /*
@@ -439,7 +429,7 @@ stuff_empty(void)
     int
 readbuf1_empty(void)
 {
-    return (readbuf1.bh_first == NULL);
+    return (readbuf1.bh_first.b_next == NULL);
 }
 
 /*
@@ -504,7 +494,7 @@ ResetRedobuff(void)
     {
 	free_buff(&old_redobuff);
 	old_redobuff = redobuff;
-	redobuff.bh_first = NULL;
+	redobuff.bh_first.b_next = NULL;
     }
 }
 
@@ -519,7 +509,7 @@ CancelRedo(void)
     {
 	free_buff(&redobuff);
 	redobuff = old_redobuff;
-	old_redobuff.bh_first = NULL;
+	old_redobuff.bh_first.b_next = NULL;
 	start_stuff();
 	while (read_readbuffers(TRUE) != NUL)
 	    ;
@@ -536,9 +526,9 @@ saveRedobuff(save_redo_T *save_redo)
     char_u	*s;
 
     save_redo->sr_redobuff = redobuff;
-    redobuff.bh_first = NULL;
+    redobuff.bh_first.b_next = NULL;
     save_redo->sr_old_redobuff = old_redobuff;
-    old_redobuff.bh_first = NULL;
+    old_redobuff.bh_first.b_next = NULL;
 
     /* Make a copy, so that ":normal ." in a function works. */
     s = get_buffcont(&save_redo->sr_redobuff, FALSE);
@@ -757,9 +747,9 @@ read_redo(int init, int old_redo)
     if (init)
     {
 	if (old_redo)
-	    bp = old_redobuff.bh_first;
+	    bp = old_redobuff.bh_first.b_next;
 	else
-	    bp = redobuff.bh_first;
+	    bp = redobuff.bh_first.b_next;
 	if (bp == NULL)
 	    return FAIL;
 	p = bp->b_str;
@@ -1382,9 +1372,9 @@ save_typeahead(tasave_T *tp)
     old_char = -1;
 
     tp->save_readbuf1 = readbuf1;
-    readbuf1.bh_first = NULL;
+    readbuf1.bh_first.b_next = NULL;
     tp->save_readbuf2 = readbuf2;
-    readbuf2.bh_first = NULL;
+    readbuf2.bh_first.b_next = NULL;
 # ifdef USE_INPUT_BUF
     tp->save_inputbuf = get_input_buf();
 # endif

src/structs.h

@@ -511,7 +511,7 @@ typedef struct buffheader buffheader_T;
 struct buffblock
 {
     buffblock_T	*b_next;	/* pointer to next buffblock */
-    char_u	b_str[];	/* contents (flexible array) */
+    char_u	b_str[1];	/* contents (actually longer) */
 };
 
 /*
@@ -519,7 +519,7 @@ struct buffblock
  */
 struct buffheader
 {
-    buffblock_T	*bh_first;	/* first block of the list */
+    buffblock_T	bh_first;	/* first (dummy) block of list */
     buffblock_T	*bh_curr;	/* buffblock for appending */
     int		bh_index;	/* index for reading */
     int		bh_space;	/* space in bh_curr for appending */

src/terminal.c

@@ -46,6 +46,9 @@
  *   switch to GUI, shell stops working. Scrollback seems wrong, command
  *   running in shell is still running.
  * - GUI: when using tabs, focus in terminal, click on tab does not work.
+ * - handle_moverect() scrolls one line at a time.  Postpone scrolling, count
+ *   the number of lines, until a redraw happens.  Then if scrolling many lines
+ *   a redraw is faster.
  * - Copy text in the vterm to the Vim buffer once in a while, so that
  *   completion works.
  * - Redrawing is slow with Athena and Motif.  Also other GUI? (Ramel Eshed)
@@ -3433,6 +3436,10 @@ parse_osc(const char *command, size_t cmdlen, void *user)
 	{
 	    char_u	*cmd = get_tv_string(&item->li_tv);
 
+	    /* Make sure an invoked command doesn't delete the buffer (and the
+	     * terminal) under our fingers. */
+	    ++term->tl_buffer->b_locked;
+
 	    item = item->li_next;
 	    if (item == NULL)
 		ch_log(channel, "Missing argument for %s", cmd);
@@ -3442,6 +3449,7 @@ parse_osc(const char *command, size_t cmdlen, void *user)
 		handle_call_command(term, channel, item);
 	    else
 		ch_log(channel, "Invalid command received: %s", cmd);
+	    --term->tl_buffer->b_locked;
 	}
     }
     else

src/testdir/test_autocmd.vim

@@ -119,7 +119,9 @@ func Test_autocmd_bufunload_avoiding_SEGV_01()
     exe 'autocmd BufUnload <buffer> ' . (lastbuf + 1) . 'bwipeout!'
   augroup END
 
-  call assert_fails('edit bb.txt', 'E937:')
+  " Todo: check for E937 generated first
+  " call assert_fails('edit bb.txt', 'E937:')
+  call assert_fails('edit bb.txt', 'E517:')
 
   autocmd! test_autocmd_bufunload
   augroup! test_autocmd_bufunload
@@ -316,7 +318,7 @@ func Test_three_windows()
   e Xtestje2
   sp Xtestje1
   call assert_fails('e', 'E937:')
-  call assert_equal('Xtestje2', expand('%'))
+  call assert_equal('Xtestje1', expand('%'))
 
   " Test changing buffers in a BufWipeout autocommand.  If this goes wrong
   " there are ml_line errors and/or a Crash.
@@ -338,7 +340,6 @@ func Test_three_windows()
 
   au!
   enew
-  bwipe! Xtestje1
   call delete('Xtestje1')
   call delete('Xtestje2')
   call delete('Xtestje3')
@@ -1181,7 +1182,9 @@ endfunc
 func Test_nocatch_wipe_all_buffers()
   " Real nasty autocommand: wipe all buffers on any event.
   au * * bwipe *
-  call assert_fails('next x', 'E93')
+  " Get E93 first?
+  " call assert_fails('next x', 'E93:')
+  call assert_fails('next x', 'E517:')
   bwipe
   au!
 endfunc

src/testdir/test_packadd.vim

@@ -40,6 +40,15 @@ func Test_packadd()
   call assert_match('/testdir/Xdir/pack/mine/opt/mytest\($\|,\)', &rtp)
   call assert_match('/testdir/Xdir/pack/mine/opt/mytest/after$', &rtp)
 
+  " NOTE: '/.../opt/myte' forwardly matches with '/.../opt/mytest'
+  call mkdir(fnamemodify(s:plugdir, ':h') . '/myte', 'p')
+  let rtp = &rtp
+  packadd myte
+
+  " Check the path of 'myte' is added
+  call assert_true(len(&rtp) > len(rtp))
+  call assert_match('/testdir/Xdir/pack/mine/opt/myte\($\|,\)', &rtp)
+
   " Check exception
   call assert_fails("packadd directorynotfound", 'E919:')
   call assert_fails("packadd", 'E471:')

src/testdir/test_popup.vim

@@ -814,5 +814,24 @@ func Test_popup_command()
   call delete('Xtest')
 endfunc
 
+func Test_popup_complete_backwards()
+  new
+  call setline(1, ['Post', 'Port', 'Po'])
+  let expected=['Post', 'Port', 'Port']
+  call cursor(3,2)
+  call feedkeys("A\<C-X>". repeat("\<C-P>", 3). "rt\<cr>", 'tx')
+  call assert_equal(expected, getline(1,'$'))
+  bwipe!
+endfunc
+
+func Test_popup_complete_backwards_ctrl_p()
+  new
+  call setline(1, ['Post', 'Port', 'Po'])
+  let expected=['Post', 'Port', 'Port']
+  call cursor(3,2)
+  call feedkeys("A\<C-P>\<C-N>rt\<cr>", 'tx')
+  call assert_equal(expected, getline(1,'$'))
+  bwipe!
+endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab

src/testdir/test_terminal.vim

@@ -1287,6 +1287,30 @@ func Test_terminal_api_call_fails()
   call delete('Xlog')
 endfunc
 
+let s:caught_e937 = 0
+
+func Tapi_Delete(bufnum, arg)
+  try
+    execute 'bdelete!' a:bufnum
+  catch /E937:/
+    let s:caught_e937 = 1
+  endtry
+endfunc
+
+func Test_terminal_api_call_fail_delete()
+  if !CanRunVimInTerminal()
+    return
+  endif
+
+  call WriteApiCall('Tapi_Delete')
+  let buf = RunVimInTerminal('-S Xscript', {})
+  call WaitFor({-> s:caught_e937 == 1})
+
+  call StopVimInTerminal(buf)
+  call delete('Xscript')
+  call ch_logfile('', '')
+endfunc
+
 func Test_terminal_ansicolors_default()
   let colors = [
 	\ '#000000', '#e00000',

src/version.c

@@ -762,6 +762,20 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1736,
+/**/
+    1735,
+/**/
+    1734,
+/**/
+    1733,
+/**/
+    1732,
+/**/
+    1731,
+/**/
+    1730,
 /**/
     1729,
 /**/