From 3a18199fcc8919220892c25c64970c7343c9e63f Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Tue, 24 May 2022 18:56:50 -0700
Subject: [PATCH] Reset 'eshell-in-pipeline-p' when interpolating commands

* lisp/eshell/esh-cmd.el (eshell-subcommand-bindings)
(eshell-command-to-value): Set 'eshell-in-pipeline-p' to nil.

* test/lisp/eshell/eshell-tests.el
(eshell-test/subcommand-reset-in-pipeline)
(eshell-test/lisp-reset-in-pipeline): New tests (bug#55620).
---
 lisp/eshell/esh-cmd.el           |  4 +++-
 test/lisp/eshell/eshell-tests.el | 29 +++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index 73c250632c..775e4c1057 100644
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -256,6 +256,7 @@ eshell-deferrable-commands
 
 (defcustom eshell-subcommand-bindings
   '((eshell-in-subcommand-p t)
+    (eshell-in-pipeline-p nil)
     (default-directory default-directory)
     (process-environment (eshell-copy-environment)))
   "A list of `let' bindings for subcommand environments."
@@ -907,7 +908,8 @@ eshell-do-command-to-value
 (defmacro eshell-command-to-value (object)
   "Run OBJECT synchronously, returning its result as a string.
 Returns a string comprising the output from the command."
-  `(let ((value (make-symbol "eshell-temp")))
+  `(let ((value (make-symbol "eshell-temp"))
+         (eshell-in-pipeline-p nil))
      (eshell-do-command-to-value ,object)))
 
 ;;;_* Iterative evaluation
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index c0affed80a..ab5d73d479 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -130,6 +130,35 @@ eshell-test/pipe-subcommand-with-pipe
    (eshell-command-result-p "echo ${*echo hi | *cat} | *cat"
                             "hi")))
 
+(ert-deftest eshell-test/subcommand-reset-in-pipeline ()
+  "Check that subcommands reset `eshell-in-pipeline-p'."
+  (skip-unless (executable-find "cat"))
+  (dolist (template '("echo {%s} | *cat"
+                      "echo ${%s} | *cat"
+                      "*cat $<%s> | *cat"))
+    (should (equal (eshell-test-command-result
+                    (format template "echo $eshell-in-pipeline-p"))
+                   nil))
+    (should (equal (eshell-test-command-result
+                    (format template "echo | echo $eshell-in-pipeline-p"))
+                   "last"))
+    (should (equal (eshell-test-command-result
+                    (format template "echo $eshell-in-pipeline-p | echo"))
+                   "first"))
+    (should (equal (eshell-test-command-result
+                    (format template
+                            "echo | echo $eshell-in-pipeline-p | echo"))
+                   "t"))))
+
+(ert-deftest eshell-test/lisp-reset-in-pipeline ()
+  "Check that interpolated Lisp forms reset `eshell-in-pipeline-p'."
+  (skip-unless (executable-find "cat"))
+  (dolist (template '("echo (%s) | *cat"
+                      "echo $(%s) | *cat"))
+    (should (equal (eshell-test-command-result
+                    (format template "format \"%s\" eshell-in-pipeline-p"))
+                   "nil"))))
+
 (ert-deftest eshell-test/redirect-buffer ()
   "Check that piping to a buffer works"
   (with-temp-buffer
-- 
2.25.1