File globbing without word splitting? - bash

Question

This is a simplified example to hopefully illustrate my problem.
I have a script that takes a parameter to be used as a wildcard. Sometimes this wildcard contains whitespace. I need to be able to use the wildcard for globbing, but word splitting is causing it to fail.
For example, consider the following example files:
$ ls -l "/home/me/dir with whitespace"
total 0
-rw-r--r-- 1 me Domain Users 0 Jun 25 16:58 file_a.txt
-rw-r--r-- 1 me Domain Users 0 Jun 25 16:58 file_b.txt
My script - simplified to use a hard coded pattern variable - looks like this:
#!/bin/bash
# Here this is hard coded, but normally it would be passed via parameter
# For example: pattern="${1}"
# The whitespace and wildcard can appear anywhere in the pattern
pattern="/home/me/dir with whitespace/file_*.txt"
# First attempt: without quoting
ls -l ${pattern}
# Result: word splitting AND globbing
# ls: cannot access /home/me/dir: No such file or directory
# ls: cannot access with: No such file or directory
# ls: cannot access whitespace/file_*.txt: No such file or directory
####################
# Second attempt: with quoting
ls -l "${pattern}"
# Result: no word splitting, no globbing
# ls: cannot access /home/me/dir with whitespace/file_*.txt: No such file or directory
Is there a way to enable globbing, but disable word splitting?
Do I have any options except manually escaping whitespace in my pattern?

Answer 1

Don't keep glob inside the quote to be able to expand it:
pattern="/home/me/dir with whitespace/file_"
ls -l "${pattern}"*
EDIT:
Based on edited question and comment you can use find:
find . -path "./$pattern" -print0 | xargs -0 ls -l

Answer 2

I finally got it!
The trick is modifying the internal field separator (IFS) to be null. This prevents word splitting on unquoted variables until IFS is reverted to its old value or until it becomes unset.
Example:
$ pattern="/home/me/dir with whitespace/file_*.txt"
$ ls -l $pattern
ls: cannot access /home/me/dir: No such file or directory
ls: cannot access with: No such file or directory
ls: cannot access whitespace/file_*.txt: No such file or directory
$ IFS=""
$ ls -l $pattern
-rw-r--r-- 1 me Domain Users 0 Jun 26 09:14 /home/me/dir with whitespace/file_a.txt
-rw-r--r-- 1 me Domain Users 0 Jun 26 09:14 /home/me/dir with whitespace/file_b.txt
$ unset IFS
$ ls -l $pattern
ls: cannot access /home/me/dir: No such file or directory
ls: cannot access with: No such file or directory
ls: cannot access whitespace/file_*.txt: No such file or directory
I found out the hard way that you cannot set and use IFS with ls. For example, this doesn't work:
$ IFS="" ls -l $pattern
This is because the command has already undergone word splitting before IFS changes.