emacs-28 9e257aecc9 1/3: Partially revert b03f74e0f2a578b1580e8b1c368665850ee7f808

[Eli Zaretskii]

branch: emacs-28
commit 9e257aecc9a3456fb3d66596862d44030f7d76c8
Author: Jim Porter <jporterbugs@gmail.com>
Commit: Eli Zaretskii <eliz@gnu.org>

    Partially revert b03f74e0f2a578b1580e8b1c368665850ee7f808
    
    That commit regressed '$<command>' forms in Eshell, due to a
    limitation/bug in how 'eshell-do-eval' works.  This fixes
    bug#54190.
    
    * lisp/eshell/esh-var.el (eshell-parse-variable-ref): Quote a lambda.
    
    * test/lisp/eshell/eshell-tests.el (eshell-test/interp-temp-cmd):
    New test.
---
 lisp/eshell/esh-var.el           | 8 ++++++--
 test/lisp/eshell/eshell-tests.el | 4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index 145a522516..081938b4e4 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -460,8 +460,12 @@ Possible options are:
                    (eshell-as-subcommand ,(eshell-parse-command cmd))
                    (ignore
                     (nconc eshell-this-command-hook
-                           (list (lambda ()
-                                   (delete-file ,temp)))))
+                           ;; Quote this lambda; it will be evaluated
+                           ;; by `eshell-do-eval', which requires very
+                           ;; particular forms in order to work
+                           ;; properly.  See bug#54190.
+                           (list (function (lambda ()
+                                   (delete-file ,temp))))))
                    (quote ,temp)))
             (goto-char (1+ end)))))))
    ((eq (char-after) ?\()
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index a9b1e2ab4e..fe4fba294f 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -130,6 +130,10 @@ e.g. \"{(+ 1 2)} 3\" => 3"
   "Interpolate Lisp form evaluation"
   (should (equal (eshell-test-command-result "+ $(+ 1 2) 3") 6)))
 
+(ert-deftest eshell-test/interp-temp-cmd ()
+  "Interpolate command result redirected to temp file"
+  (should (equal (eshell-test-command-result "cat $<echo hi>") "hi")))
+
 (ert-deftest eshell-test/interp-concat ()
   "Interpolate and concat command"
   (should (equal (eshell-test-command-result "+ ${+ 1 2}3 3") 36)))