master 4450c8bdd9 1/3: Consider subcommands when deciding to invoke Eshell command directly

[Lars Ingebrigtsen]

branch: master
commit 4450c8bdd93d1b2e7f276e26be2cc37372034c22
Author: Jim Porter <jporterbugs@gmail.com>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    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).
---
 lisp/eshell/esh-cmd.el           | 57 ++++++++++++++++++++++++++++++----------
 test/lisp/eshell/eshell-tests.el | 23 ++++++++++++++++
 2 files changed, 66 insertions(+), 14 deletions(-)

diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index a2d7d9431a..25e3a5a205 100644
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -903,21 +903,50 @@ at the moment are:
   "Completion for the `debug' command."
   (while (pcomplete-here '("errors" "commands"))))
 
+(defun eshell--invoke-command-directly (command)
+  "Determine whether the given COMMAND can be invoked directly.
+COMMAND should be a non-top-level Eshell command in parsed form.
+
+A command can be invoked directly if all of the following are true:
+
+* The command is of the form
+  \"(eshell-trap-errors (eshell-named-command NAME ARGS))\",
+  where ARGS is optional.
+
+* NAME is a string referring to an alias function and isn't a
+  complex command (see `eshell-complex-commands').
+
+* Any argument in ARGS that calls a subcommand can also be
+  invoked directly."
+  (when (and (eq (car command) 'eshell-trap-errors)
+             (eq (car (cadr command)) 'eshell-named-command))
+    (let ((name (cadr (cadr command)))
+          (args (cdr-safe (nth 2 (cadr command)))))
+      (and name (stringp name)
+          (not (member name eshell-complex-commands))
+          (catch 'simple
+            (dolist (pred eshell-complex-commands t)
+              (when (and (functionp pred)
+                         (funcall pred name))
+                (throw 'simple nil))))
+          (eshell-find-alias-function name)
+           (catch 'indirect-subcommand
+            (dolist (arg args t)
+               (pcase arg
+                 (`(eshell-escape-arg
+                    (let ,_
+                      (eshell-convert
+                       (eshell-command-to-value
+                        (eshell-as-subcommand ,subcommand)))))
+                  (unless (eshell--invoke-command-directly subcommand)
+                    (throw 'indirect-subcommand nil))))))))))
+
 (defun eshell-invoke-directly (command)
-  (let ((base (cadr (nth 2 (nth 2 (cadr command))))) name)
-    (if (and (eq (car base) 'eshell-trap-errors)
-            (eq (car (cadr base)) 'eshell-named-command))
-       (setq name (cadr (cadr base))))
-    (and name (stringp name)
-        (not (member name eshell-complex-commands))
-        (catch 'simple
-          (progn
-           (dolist (pred eshell-complex-commands)
-             (if (and (functionp pred)
-                      (funcall pred name))
-                 (throw 'simple nil)))
-           t))
-        (eshell-find-alias-function name))))
+  "Determine whether the given COMMAND can be invoked directly.
+COMMAND should be a top-level Eshell command in parsed form, as
+produced by `eshell-parse-command'."
+  (let ((base (cadr (nth 2 (nth 2 (cadr command))))))
+    (eshell--invoke-command-directly base)))
 
 (defun eshell-eval-command (command &optional input)
   "Evaluate the given COMMAND iteratively."
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index aef1447907..c4cb9bf485 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)")))