vim-patch:9.0.1946: filename expansion using ** in bash may fail

Problem:  filename expansion using ** in bash may fail
Solution: Try to enable the globstar setting

Starting with bash 4.0 it supports extended globbing using the globstar
shell option. This makes matching recursively below a certain directory
using the ** pattern work as expected nowadays.  However, we need to
explicitly enable this using the 'shopt -s globstar' bash command.

So let's check the bash environment variable $BASH_VERSINFO (which is
supported since bash 3.0 and conditionally enable the globstar option,
if the major version is at least 4. For older bashs, this at least
shouldn't cause errors (unless one is using really ancient bash 2.X or
something).

closes: vim/vim#13002
closes: vim/vim#13144

9eb1ce5315

Co-authored-by: Christian Brabandt <cb@256bit.org>

test/old/testdir/test_functions.vim

@@ -3281,4 +3281,23 @@ func Test_fullcommand()
   call assert_equal('', fullcommand(10))
 endfunc
 
+" Test for glob() with shell special patterns
+func Test_glob_extended_bash()
+  CheckExecutable bash
+  let _shell = &shell
+  set shell=bash
+
+  call mkdir('Xtestglob/foo/bar/src', 'p')
+  call writefile([], 'Xtestglob/foo/bar/src/foo.sh')
+  call writefile([], 'Xtestglob/foo/bar/src/foo.h')
+  call writefile([], 'Xtestglob/foo/bar/src/foo.cpp')
+
+  " Sort output of glob() otherwise we end up with different
+  " ordering depending on whether file system is case-sensitive.
+  let expected = ['Xtestglob/foo/bar/src/foo.cpp', 'Xtestglob/foo/bar/src/foo.h']
+  call assert_equal(expected, sort(glob('Xtestglob/**/foo.{h,cpp}', 0, 1)))
+  call delete('Xtestglob', 'rf')
+  let &shell=_shell
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab