bug#67717: 29.1; Eshell doesn't handle script with "#!/usr/bin/env python3 -ESs"

[Sean Devlin]

Hi folks,

From Eshell, I'm trying to invoke a script with the interpreter line:

#!/usr/bin/env python3 -ESs

Instead of invoking the script, Eshell prints the line:

env: python3 -ESs: No such file or directory

Recipe:

1. Create a file with contents:

#!/usr/bin/env python3 -ESs
from sys import argv
print(argv)

2. M-x eshell
3. In Eshell, run the commands:

$ chmod +x /path/to/file
$ /path/to/file one two three

Expectation: Eshell should print the line:

['/path/to/file', 'one', 'two', 'three']

Result: Eshell prints the line:

env: python3 -ESs: No such file or directory

I think the problem is somewhere in esh-ext.el. Tracing the functions
eshell-find-interpreter and eshell-script-interpreter during execution
yields the following trace:

1 -> (eshell-find-interpreter "/path/to/file" ("one" "two" "three") nil)
| 2 -> (eshell-script-interpreter "/path/to/file")
| 2 <- eshell-script-interpreter: ("/usr/bin/env" "python3 -ESs" 
"/path/to/file")
| 2 -> (eshell-find-interpreter "/usr/bin/env" ("one" "two" "three") t)
| 2 <- eshell-find-interpreter: ("/usr/bin/env")
1 <- eshell-find-interpreter: ("/usr/bin/env" "python3 -ESs" "/path/to/file")

It looks like "python3 -ESs" has been parsed as a single argument to
env, but it should be split into two arguments.

Thanks!

In GNU Emacs 29.1 (build 1, aarch64-apple-darwin21.6.0, NS
appkit-2113.60 Version 12.6.6 (Build 21G646)) of 2023-08-16 built on
armbob.lan
Windowing system distributor 'Apple', version 10.3.2487
System Description:  macOS 14

Configured using:
'configure --with-ns '--enable-locallisppath=/Library/Application
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