Further improve determination of when commands can be invoked directly

This covers the case when a subcommand is to be invoked in more places
than before, for example when a subcommand is concatenated in an
argument.

* lisp/eshell/esh-cmd.el (eshell--find-subcommands): New fuction.
(eshell--invoke-command-directly): Use 'eshell-find-subcommands'.

* test/lisp/eshell/eshell-tests.el
(eshell-test/interp-cmd-external-concat): New test (bug#30725).

1 files changed, 7 insertions, 0 deletions

diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index c4cb9bf4850..1a7ab0ab06f 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -167,6 +167,13 @@ e.g. \"{(+ 1 2)} 3\" => 3"
    (eshell-command-result-p "echo ${*echo hi}"
                             "hi\n")))
 
+(ert-deftest eshell-test/interp-cmd-external-concat ()
+  "Interpolate command result from external command with concatenation"
+  (skip-unless (executable-find "echo"))
+  (with-temp-eshell
+   (eshell-command-result-p "echo ${echo hi}-${*echo there}"
+                            "hi-there\n")))
+
 (ert-deftest eshell-test/window-height ()
   "$LINES should equal (window-height)"
   (should (eshell-test-command-result "= $LINES (window-height)")))