* lisp/eshell/em-extpipe.el (em-extpipe--or-with-catch): New macro.
(eshell-parse-external-pipeline): Use new macro to treat
`eshell-incomplete' as a failure of the parse function to move us
forward (Bug#54603). Thanks to Jim Porter <jporterbugs@gmail.com> for
the report and for help isolating the problem.
* test/lisp/eshell/eshell-tests.el
(eshell-test/lisp-command-with-quote): New test for Bug#54603, thanks
to Jim Porter <jporterbugs@gmail.com> (bug#54603).
* lisp/eshell/em-extpipe.el (eshell-parse-external-pipeline): Fix
misinterpreting sharp-quoted symbols as the beginning of single-quoted
strings (Bug#53518). Add protection against a possible infinite loop.
* test/lisp/eshell/em-extpipe-tests.el (em-extpipe-test-17): New
test (bug#53518).