patch 9.2.1171: Vim9: lambda split over lines gives an internal error

Problem:  In a {} block of :autocmd or :command, a lambda whose
          expression continues on the next lines gives E341 and loops
          forever, or E342 when "|" and a command follow it.
Solution: Stop splitting the lambda into lines at the end of the
          expression.

fixes:  #21453
closes: #21455

Assisted-by: Claude
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_autocmd.vim

@@ -4070,6 +4070,34 @@ func Test_autocmd_with_block()
   augroup END
 endfunc
 
+" Test for a lambda in an :autocmd block with the expression split over lines
+func Test_autocmd_block_multiline_lambda()
+  let lines =<< trim END
+      vim9script
+      autocmd CmdlineEnter * {
+          g:Lambda = () => true ?
+              'yes' :
+              'no' | g:after = 'done'
+        }
+      doautocmd CmdlineEnter
+      assert_equal('yes', g:Lambda())
+      assert_equal('done', g:after)
+
+      au! CmdlineEnter
+      autocmd CmdlineEnter * {
+          g:Lambda = () => false ?
+              'yes' :
+              'no'
+        }
+      doautocmd CmdlineEnter
+      assert_equal('no', g:Lambda())
+  END
+  call v9.CheckScriptSuccess(lines)
+
+  unlet g:Lambda g:after
+  au! CmdlineEnter
+endfunc
+
 " Test for a backslash line continuation in an :autocmd command
 func Test_autocmd_line_continuation()
   let lines =<< trim END

src/userfunc.c

@@ -1830,13 +1830,13 @@ get_lambda_tv(
 	{
 	    // Add more lines, split by line breaks.  Thus is used when a
 	    // lambda with { cmds } is encountered.
-	    while (*line_end == '\n')
+	    while (line_end < end && *line_end == '\n')
 	    {
 		if (ga_grow(&newlines, 1) == FAIL)
 		    goto errret;
 		start = line_end + 1;
 		line_end = vim_strchr(start, '\n');
-		if (line_end == NULL)
+		if (line_end == NULL || line_end > end)
 		    line_end = end;
 		((char_u **)(newlines.ga_data))[newlines.ga_len++] =
 					 vim_strnsave(start, line_end - start);

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1171,
 /**/
     1170,
 /**/