patch 8.2.4876: MS-Windows: Shift-BS results in strange char in powershell

Problem:    MS-Windows: Shift-BS results in strange character in powershell.
Solution:   Add K_S_BS. (Christian Brabandt, closes #10283, closes #10279)

src/edit.c

@@ -963,6 +963,7 @@ doESCkey:
 	    break;
 
 	case K_BS:	// delete character before the cursor
+	case K_S_BS:
 	case Ctrl_H:
 	    did_backspace = ins_bs(c, BACKSPACE_CHAR, &inserted_space);
 	    auto_format(FALSE, TRUE);

src/keymap.h

@@ -276,6 +276,7 @@ enum key_extra
     , KE_CANCEL = 102		// return from vgetc()
     , KE_COMMAND = 103		// <Cmd> special key
     , KE_SCRIPT_COMMAND = 104	// <ScriptCmd> special key
+    , KE_S_BS = 105	        // shift + <BS>
 };
 
 /*
@@ -299,6 +300,7 @@ enum key_extra
 #define K_C_END		TERMCAP2KEY(KS_EXTRA, KE_C_END)
 #define K_TAB		TERMCAP2KEY(KS_EXTRA, KE_TAB)
 #define K_S_TAB		TERMCAP2KEY('k', 'B')
+#define K_S_BS		TERMCAP2KEY(KS_EXTRA, KE_S_BS)
 
 // extra set of function keys F1-F4, for vt100 compatible xterm
 #define K_XF1		TERMCAP2KEY(KS_EXTRA, KE_XF1)

src/term.c

@@ -688,6 +688,7 @@ static struct builtin_term builtin_termcaps[] =
     {K_K8,		"\316\372"},
     {K_K9,		"\316\376"},
     {K_BS,		"\316x"},
+    {K_S_BS,            "\316y"},
 # endif
 
 # if defined(VMS) || defined(ALL_BUILTIN_TCAPS)

src/testdir/shared.vim

@@ -248,7 +248,11 @@ let g:valgrind_cnt = 1
 func GetVimCommand(...)
   if !filereadable('vimcmd')
     echo 'Cannot read the "vimcmd" file, falling back to ../vim.'
-    let lines = ['../vim']
+    if !has("win32")
+      let lines = ['../vim']
+    else
+      let lines = ['..\vim.exe']
+    endif
   else
     let lines = readfile('vimcmd')
   endif

src/testdir/test_edit.vim

@@ -2148,5 +2148,31 @@ func Test_edit_overlong_file_name()
   bwipe!
 endfunc
 
+func Test_edit_shift_bs()
+  CheckMSWindows
+
+  " FIXME: this works interactively, but the test fails
+  throw 'Skipped: Shift-Backspace Test not working correctly :('
+
+  " Need to run this in Win32 Terminal, do not use CheckRunVimInTerminal
+  if !has("terminal")
+    return
+  endif
+
+  " Shift Backspace should work like Backspace in insert mode
+  let lines =<< trim END
+    call setline(1, ['abc'])
+  END
+  call writefile(lines, 'Xtest_edit_shift_bs')
+
+  let buf = RunVimInTerminal('-S Xtest_edit_shift_bs', #{rows: 3})
+  call term_sendkeys(buf, "A\<S-BS>-\<esc>")
+  call TermWait(buf, 50)
+  call assert_equal('ab-', term_getline(buf, 1))
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('Xtest_edit_shift_bs')
+endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4876,
 /**/
     4875,
 /**/