patch 8.2.3530: ":buf \{a}" fails while ":edit \{a}" works

Problem:    ":buf \{a}" fails while ":edit \{a}" works.
Solution:   Unescape "\{". (closes #8917)

src/cmdexpand.c

@@ -48,6 +48,8 @@ ExpandEscape(
 {
     int		i;
     char_u	*p;
+    int		vse_what = xp->xp_context == EXPAND_BUFFERS
+						       ? VSE_BUFFER : VSE_NONE;
 
     // May change home directory back to "~"
     if (options & WILD_HOME_REPLACE)
@@ -84,9 +86,10 @@ ExpandEscape(
 		    }
 		}
 #ifdef BACKSLASH_IN_FILENAME
-		p = vim_strsave_fnameescape(files[i], FALSE);
+		p = vim_strsave_fnameescape(files[i], vse_what);
 #else
-		p = vim_strsave_fnameescape(files[i], xp->xp_shell);
+		p = vim_strsave_fnameescape(files[i],
+					  xp->xp_shell ? VSE_SHELL : vse_what);
 #endif
 		if (p != NULL)
 		{

src/evalfunc.c

@@ -3886,7 +3886,7 @@ f_fnameescape(typval_T *argvars, typval_T *rettv)
 	return;
 
     rettv->vval.v_string = vim_strsave_fnameescape(
-					   tv_get_string(&argvars[0]), FALSE);
+					 tv_get_string(&argvars[0]), VSE_NONE);
     rettv->v_type = VAR_STRING;
 }
 

src/ex_getln.c

@@ -3894,27 +3894,32 @@ ccheck_abbr(int c)
 }
 
 /*
- * Escape special characters in "fname" for when used as a file name argument
+ * Escape special characters in "fname", depending on "what":
- * after a Vim command, or, when "shell" is non-zero, a shell command.
+ * VSE_NONE: for when used as a file name argument after a Vim command.
+ * VSE_SHELL: for a shell command.
+ * VSE_BUFFER: for the ":buffer" command.
  * Returns the result in allocated memory.
  */
     char_u *
-vim_strsave_fnameescape(char_u *fname, int shell UNUSED)
+vim_strsave_fnameescape(char_u *fname, int what)
 {
     char_u	*p;
 #ifdef BACKSLASH_IN_FILENAME
     char_u	buf[20];
     int		j = 0;
 
-    // Don't escape '[', '{' and '!' if they are in 'isfname'.
+    // Don't escape '[', '{' and '!' if they are in 'isfname' and for the
-    for (p = PATH_ESC_CHARS; *p != NUL; ++p)
+    // ":buffer" command.
+    for (p = what == VSE_BUFFER ? BUFFER_ESC_CHARS : PATH_ESC_CHARS;
+								*p != NUL; ++p)
 	if ((*p != '[' && *p != '{' && *p != '!') || !vim_isfilec(*p))
 	    buf[j++] = *p;
     buf[j] = NUL;
     p = vim_strsave_escaped(fname, buf);
 #else
-    p = vim_strsave_escaped(fname, shell ? SHELL_ESC_CHARS : PATH_ESC_CHARS);
+    p = vim_strsave_escaped(fname, what == VSE_SHELL ? SHELL_ESC_CHARS
-    if (shell && csh_like_shell() && p != NULL)
+		    : what == VSE_BUFFER ? BUFFER_ESC_CHARS : PATH_ESC_CHARS);
+    if (what == VSE_SHELL && csh_like_shell() && p != NULL)
     {
 	char_u	    *s;
 

src/normal.c

@@ -3741,7 +3741,7 @@ nv_ident(cmdarg_T *cap)
 	ptr = vim_strnsave(ptr, n);
 	if (kp_ex)
 	    // Escape the argument properly for an Ex command
-	    p = vim_strsave_fnameescape(ptr, FALSE);
+	    p = vim_strsave_fnameescape(ptr, VSE_NONE);
 	else
 	    // Escape the argument properly for a shell command
 	    p = vim_strsave_shellescape(ptr, TRUE, TRUE);

src/proto/ex_getln.pro

@@ -26,7 +26,7 @@ void redrawcmd(void);
 void compute_cmdrow(void);
 void cursorcmd(void);
 void gotocmdline(int clr);
-char_u *vim_strsave_fnameescape(char_u *fname, int shell);
+char_u *vim_strsave_fnameescape(char_u *fname, int what);
 void escape_fname(char_u **pp);
 void tilde_replace(char_u *orig_pat, int num_files, char_u **files);
 cmdline_info_T *get_cmdline_info(void);

src/session.c

@@ -43,7 +43,7 @@ ses_put_fname(FILE *fd, char_u *name, unsigned *flagp)
     }
 
     // escape special characters
-    p = vim_strsave_fnameescape(sname, FALSE);
+    p = vim_strsave_fnameescape(sname, VSE_NONE);
     vim_free(sname);
     if (p == NULL)
 	return FAIL;

src/terminal.c

@@ -667,7 +667,7 @@ term_start(
 
 	    if (s == NULL)
 		break;
-	    p = vim_strsave_fnameescape(s, FALSE);
+	    p = vim_strsave_fnameescape(s, VSE_NONE);
 	    if (p == NULL)
 		break;
 	    ga_concat(&ga, p);

src/testdir/test_cmdline.vim

@@ -900,6 +900,12 @@ func Test_cmdline_complete_various()
   call feedkeys(":unlet one two\<C-A>\<C-B>\"\<CR>", 'xt')
   call assert_equal("\"unlet one two", @:)
 
+  " completion for the :buffer command with curlies
+  edit \{someFile}
+  call feedkeys(":buf someFile\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal("\"buf {someFile}", @:)
+  bwipe {someFile}
+
   " completion for the :bdelete command
   call feedkeys(":bdel a b c\<C-A>\<C-B>\"\<CR>", 'xt')
   call assert_equal("\"bdel a b c", @:)

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3530,
 /**/
     3529,
 /**/

src/vim.h

@@ -291,6 +291,7 @@
 #endif
 #ifdef BACKSLASH_IN_FILENAME
 # define PATH_ESC_CHARS ((char_u *)" \t\n*?[{`%#'\"|!<")
+# define BUFFER_ESC_CHARS ((char_u *)" \t\n*?[`%#'\"|!<")
 #else
 # ifdef VMS
     // VMS allows a lot of characters in the file name
@@ -300,6 +301,7 @@
 #  define PATH_ESC_CHARS ((char_u *)" \t\n*?[{`$\\%#'\"|!<")
 #  define SHELL_ESC_CHARS ((char_u *)" \t\n*?[{`$\\%#'\"|!<>();&")
 # endif
+#  define BUFFER_ESC_CHARS ((char_u *)" \t\n*?[`$\\%#'\"|!<")
 #endif
 
 // length of a buffer to store a number in ASCII (64 bits binary + NUL)
@@ -2766,5 +2768,9 @@ long elapsed(DWORD start_tick);
 #define UC_BUFFER	1	// -buffer: local to current buffer
 #define UC_VIM9		2	// {} argument: Vim9 syntax.
 
+// flags used by vim_strsave_escaped()
+#define VSE_NONE	0
+#define VSE_SHELL	1	// escape for a shell command
+#define VSE_BUFFER	2	// escape for a ":buffer" command
 
 #endif // VIM__H

src/vim9execute.c

@@ -1147,7 +1147,8 @@ do_2string(typval_T *tv, int is_2string_any, int tolerant)
 				    while ((e = vim_strchr(s, '\n')) != NULL)
 				    {
 					*e = NUL;
-					p = vim_strsave_fnameescape(s, FALSE);
+					p = vim_strsave_fnameescape(s,
+								     VSE_NONE);
 					if (p != NULL)
 					{
 					    ga_concat(&ga, p);