fix: make_filter_cmd for :! powershell #15913

Problem:
Nvim fails to create tempfile "…/nvim6UJx04/7" when 'shell' is set to
pwsh (PowerShell Core). This breaks filtered shell commands ":{range}!".
With shell set to cmd, it works.

Solution:
PowerShell doesn't use "<" for stdin redirection. Instead, use
"-RedirectStandardInput".

Closes #15913

runtime/doc/options.txt

@@ -5324,9 +5324,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 	unescaping, so to keep yourself sane use |:let-&| like shown above.
 							*shell-powershell*
 	To use PowerShell: >
-		let &shell = has('win32') ? 'powershell' : 'pwsh'
+		let &shell = executable('pwsh') ? 'pwsh' : 'powershell'
 		let &shellcmdflag = '-NoLogo -NoProfile -ExecutionPolicy RemoteSigned -Command [Console]::InputEncoding=[Console]::OutputEncoding=[System.Text.Encoding]::UTF8;'
-		let &shellredir = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
+		let &shellredir = '-RedirectStandardOutput %s -NoNewWindow -Wait'
 		let &shellpipe = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
 		set shellquote= shellxquote=
 

src/nvim/ex_cmds.c

@@ -1571,14 +1571,18 @@ char_u *make_filter_cmd(char_u *cmd, char_u *itmp, char_u *otmp)
 #else
     false;
 #endif
+  bool is_pwsh = STRNCMP(invocation_path_tail(p_sh, NULL), "pwsh", 4) == 0
+                 || STRNCMP(invocation_path_tail(p_sh, NULL), "powershell", 10) == 0;
 
   size_t len = STRLEN(cmd) + 1;  // At least enough space for cmd + NULL.
 
   len += is_fish_shell ?  sizeof("begin; " "; end") - 1
-                       :  sizeof("(" ")") - 1;
+                       :  is_pwsh ? STRLEN("Start-Process ")
+                                  : sizeof("(" ")") - 1;
 
   if (itmp != NULL) {
-    len += STRLEN(itmp) + sizeof(" { " " < " " } ") - 1;
+    len += is_pwsh  ? STRLEN(itmp) + STRLEN(" -RedirectStandardInput ")
+                    : STRLEN(itmp) + sizeof(" { " " < " " } ") - 1;
   }
   if (otmp != NULL) {
     len += STRLEN(otmp) + STRLEN(p_srr) + 2;  // two extra spaces ("  "),
@@ -1588,7 +1592,10 @@ char_u *make_filter_cmd(char_u *cmd, char_u *itmp, char_u *otmp)
 #if defined(UNIX)
   // Put delimiters around the command (for concatenated commands) when
   // redirecting input and/or output.
-  if (itmp != NULL || otmp != NULL) {
+  if (is_pwsh) {
+    xstrlcpy(buf, "Start-Process ", len);
+    xstrlcat(buf, (char *)cmd, len);
+  } else if (itmp != NULL || otmp != NULL) {
     char *fmt = is_fish_shell ? "begin; %s; end"
                               :       "(%s)";
     vim_snprintf(buf, len, fmt, (char *)cmd);
@@ -1597,13 +1604,22 @@ char_u *make_filter_cmd(char_u *cmd, char_u *itmp, char_u *otmp)
   }
 
   if (itmp != NULL) {
-    xstrlcat(buf, " < ", len - 1);
+    if (is_pwsh) {
+      xstrlcat(buf, " -RedirectStandardInput ", len - 1);
+    } else {
+      xstrlcat(buf, " < ", len - 1);
+    }
     xstrlcat(buf, (const char *)itmp, len - 1);
   }
 #else
   // For shells that don't understand braces around commands, at least allow
   // the use of commands in a pipe.
-  xstrlcpy(buf, (char *)cmd, len);
+  if (is_pwsh) {
+    xstrlcpy(buf, "Start-Process ", len);
+    xstrlcat(buf, (char *)cmd, len);
+  } else {
+    xstrlcpy(buf, (char *)cmd, len);
+  }
   if (itmp != NULL) {
     // If there is a pipe, we have to put the '<' in front of it.
     // Don't do this when 'shellquote' is not empty, otherwise the
@@ -1614,7 +1630,11 @@ char_u *make_filter_cmd(char_u *cmd, char_u *itmp, char_u *otmp)
         *p = NUL;
       }
     }
-    xstrlcat(buf, " < ", len);
+    if (is_pwsh) {
+      xstrlcat(buf, " -RedirectStandardInput ", len);
+    } else {
+      xstrlcat(buf, " < ", len);
+    }
     xstrlcat(buf, (const char *)itmp, len);
     if (*p_shq == NUL) {
       const char *const p = find_pipe((const char *)cmd);

test/functional/helpers.lua

@@ -511,9 +511,9 @@ function module.set_shell_powershell()
   module.exec([[
     let &shell = ']]..shell..[['
     set shellquote= shellxquote=
-    let &shellpipe = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
-    let &shellredir = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
     let &shellcmdflag = '-NoLogo -NoProfile -ExecutionPolicy RemoteSigned -Command ]]..cmd..[['
+    let &shellpipe = '2>&1 | Out-File -Encoding UTF8 %s; exit $LastExitCode'
+    let &shellredir = '-RedirectStandardOutput %s -NoNewWindow -Wait'
   ]])
 end
 

test/functional/vimscript/system_spec.lua

@@ -6,6 +6,8 @@ local eq, call, clear, eval, feed_command, feed, nvim =
   helpers.eq, helpers.call, helpers.clear, helpers.eval, helpers.feed_command,
   helpers.feed, helpers.nvim
 local command = helpers.command
+local insert = helpers.insert
+local expect = helpers.expect
 local exc_exec = helpers.exc_exec
 local iswin = helpers.iswin
 local os_kill = helpers.os_kill
@@ -630,3 +632,29 @@ describe('systemlist()', function()
   end)
 
 end)
+
+it(':{range}! works with powershell for filter and redirection #16271', function()
+  clear()
+  if not helpers.has_powershell() then
+    pending("not tested; powershell was not found", function() end)
+    return
+  end
+  local screen = Screen.new(500, 8)
+  screen:attach()
+  helpers.set_shell_powershell()
+  insert([[
+    3
+    1
+    4
+    2]])
+  feed(':4verbose %!sort<cr>')
+  screen:expect{
+    any=[[Executing command: "Start%-Process sort %-RedirectStandardInput .* %-RedirectStandardOutput .* %-NoNewWindow %-Wait".*4 lines filtered.*Press ENTER or type command to continue]]
+  }
+  feed('<CR>')
+  expect([[
+    1
+    2
+    3
+    4]])
+end)