Consider subcommands when deciding to invoke Eshell command directly

When an Eshell command contains an asynchronous subcommand (such as
calling an external process), it must be evaluated iteratively.  See
bug#30725.

* lisp/eshell/esh-cmd.el (eshell-invoke-command): Move most of the
logic from here...
(eshell--invoke-command-directly): ... to here. Also add checks for
subcommands.

* test/lisp/eshell/eshell-tests.el (eshell-test--max-subprocess-time):
New variable.
(eshell-wait-for-subprocess): New function.
(eshell-command-result-p): Use 'eshell-wait-for-subprocess'.
(eshell-test/interp-cmd-external): New test (bug#30725).

1 files changed, 23 insertions, 0 deletions

diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index aef14479078..c4cb9bf4850 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -30,6 +30,10 @@
 (require 'esh-mode)
 (require 'eshell)
 
+(defvar eshell-test--max-subprocess-time 5
+  "The maximum amount of time to wait for a subprocess to finish, in seconds.
+See `eshell-wait-for-subprocess'.")
+
 (defmacro with-temp-eshell (&rest body)
   "Evaluate BODY in a temporary Eshell buffer."
   `(ert-with-temp-directory eshell-directory-name
@@ -44,6 +48,17 @@
          (let (kill-buffer-query-functions)
            (kill-buffer eshell-buffer))))))
 
+(defun eshell-wait-for-subprocess ()
+  "Wait until there is no interactive subprocess running in Eshell.
+If this takes longer than `eshell-test--max-subprocess-time',
+raise an error."
+  (let ((start (current-time)))
+    (while (eshell-interactive-process)
+      (when (> (float-time (time-since start))
+               eshell-test--max-subprocess-time)
+        (error "timed out waiting for subprocess"))
+      (sit-for 0.1))))
+
 (defun eshell-insert-command (text &optional func)
   "Insert a command at the end of the buffer."
   (goto-char eshell-last-output-end)
@@ -59,6 +74,7 @@
 (defun eshell-command-result-p (text regexp &optional func)
   "Insert a command at the end of the buffer."
   (eshell-insert-command text func)
+  (eshell-wait-for-subprocess)
   (eshell-match-result regexp))
 
 (defvar eshell-history-file-name)
@@ -144,6 +160,13 @@ e.g. \"{(+ 1 2)} 3\" => 3"
   "Interpolate and concat two Lisp forms"
   (should (equal (eshell-test-command-result "+ $(+ 1 2)$(+ 1 2) 3") 36)))
 
+(ert-deftest eshell-test/interp-cmd-external ()
+  "Interpolate command result from external command"
+  (skip-unless (executable-find "echo"))
+  (with-temp-eshell
+   (eshell-command-result-p "echo ${*echo hi}"
+                            "hi\n")))
+
 (ert-deftest eshell-test/window-height ()
   "$LINES should equal (window-height)"
   (should (eshell-test-command-result "= $LINES (window-height)")))