From 5f0f60ebcce61954324c172700fa8ac924b605f7 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Fri, 8 Jul 2022 18:41:07 -0700
Subject: [PATCH 2/3] Allow Eshell variable aliases to point to other aliases

In particular, this resolves an issue where '$+' referenced the real
environment variable '$PWD' instead of the Eshell variable alias of
the same name.  This meant that changing directories in Eshell
wouldn't update the value of '$+'.

* lisp/eshell/esh-var.el (eshell-get-variable): Allow Eshell variable
aliaes to point to other aliases.

* test/lisp/eshell/em-dirs-tests.el (em-dirs-test/pwd-var)
(em-dirs-test/short-pwd-var): Adapt tests to check this case
(bug#56509).
---
 lisp/eshell/esh-var.el            | 41 +++++++++++++++----------------
 test/lisp/eshell/em-dirs-tests.el | 10 +++++---
 2 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index 5092d2c6a5..e1535c1c5d 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -549,27 +549,26 @@ eshell-get-variable
   "Get the value for the variable NAME.
 INDICES is a list of index-lists (see `eshell-parse-indices').
 If QUOTED is non-nil, this was invoked inside double-quotes."
-  (let* ((alias (assoc name eshell-variable-aliases-list))
-	 (var (if alias
-		  (cadr alias)
-		name)))
-    (if (and alias (functionp var))
-	(funcall var indices)
-      (eshell-apply-indices
-       (cond
-	((stringp var)
-	 (let ((sym (intern-soft var)))
-	   (if (and sym (boundp sym)
-		    (or eshell-prefer-lisp-variables
-			(memq sym eshell--local-vars) ; bug#15372
-			(not (getenv var))))
-	       (symbol-value sym)
-	     (getenv var))))
-	((symbolp var)
-	 (symbol-value var))
-	(t
-	 (error "Unknown variable `%s'" (eshell-stringify var))))
-       indices quoted))))
+  (if-let ((alias (assoc name eshell-variable-aliases-list)))
+      (let ((target (cadr alias)))
+        (cond
+         ((functionp target)
+          (funcall target indices))
+         ((symbolp target)
+          (eshell-apply-indices (symbol-value target) indices quoted))
+         (t
+          (eshell-get-variable target indices quoted))))
+    (unless (stringp name)
+      (error "Unknown variable `%s'" (eshell-stringify name)))
+    (eshell-apply-indices
+     (let ((sym (intern-soft name)))
+       (if (and sym (boundp sym)
+		(or eshell-prefer-lisp-variables
+		    (memq sym eshell--local-vars) ; bug#15372
+		    (not (getenv name))))
+	   (symbol-value sym)
+	 (getenv name)))
+     indices quoted)))
 
 (defun eshell-apply-indices (value indices &optional quoted)
   "Apply to VALUE all of the given INDICES, returning the sub-result.
diff --git a/test/lisp/eshell/em-dirs-tests.el b/test/lisp/eshell/em-dirs-tests.el
index eb27acd208..69480051e4 100644
--- a/test/lisp/eshell/em-dirs-tests.el
+++ b/test/lisp/eshell/em-dirs-tests.el
@@ -36,13 +36,15 @@
 
 (ert-deftest em-dirs-test/pwd-var ()
   "Test using the $PWD variable."
-  (should (equal (eshell-test-command-result "echo $PWD")
-                 (expand-file-name (eshell/pwd)))))
+  (let ((default-directory "/some/path"))
+    (should (equal (eshell-test-command-result "echo $PWD")
+                   (expand-file-name default-directory)))))
 
 (ert-deftest em-dirs-test/short-pwd-var ()
   "Test using the $+ (current directory) variable."
-  (should (equal (eshell-test-command-result "echo $+")
-                 (expand-file-name (eshell/pwd)))))
+  (let ((default-directory "/some/path"))
+    (should (equal (eshell-test-command-result "echo $+")
+                   (expand-file-name default-directory)))))
 
 (ert-deftest em-dirs-test/oldpwd-var ()
   "Test using the $OLDPWD variable."
-- 
2.25.1