From 005959bbe9998185bf9600387aa308ffabba0070 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Sat, 19 Mar 2022 17:52:55 -0700
Subject: [PATCH 3/3] Add 'G' argument predicate in Eshell

* lisp/eshell/em-pred.el (eshell-predicate-alist): Add 'G' predicate.
(eshell-predicate-help-string): Document it.

* test/lisp/eshell/em-pred-tests.el
(em-pred-test/predicate-effective-gid): New test.

* doc/misc/eshell.text (Argument Predication): Document 'G' predicate.
---
 doc/misc/eshell.texi              | 3 +++
 lisp/eshell/em-pred.el            | 9 +++++----
 test/lisp/eshell/em-pred-tests.el | 8 ++++++++
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/doc/misc/eshell.texi b/doc/misc/eshell.texi
index 2b49ddb03c..89f5b953f5 100644
--- a/doc/misc/eshell.texi
+++ b/doc/misc/eshell.texi
@@ -1266,6 +1266,9 @@ Argument Predicates
 @item @code{U}
 Matches files owned by the current effective user ID.
 
+@item @code{G}
+Matches files owned by the current effective group ID.
+
 @item @code{l@option{[+-]}@var{n}}
 Matches files with @var{n} links.  With @option{+} (or @option{-}),
 matches files with more than (or less than) @var{n} links,
diff --git a/lisp/eshell/em-pred.el b/lisp/eshell/em-pred.el
index 8afc86dd41..eb5109b82d 100644
--- a/lisp/eshell/em-pred.el
+++ b/lisp/eshell/em-pred.el
@@ -88,10 +88,10 @@ eshell-predicate-alist
             (if (file-exists-p file)
                 (= (file-attribute-user-id (file-attributes file))
                    (user-uid)))))
-    ;; (?G . (lambda (file)               ; owned by effective gid
-    ;;         (if (file-exists-p file)
-    ;;             (= (file-attribute-user-id (file-attributes file))
-    ;;                (user-uid)))))
+    (?G . (lambda (file)               ; owned by effective gid
+            (if (file-exists-p file)
+                (= (file-attribute-group-id (file-attributes file))
+                   (group-gid)))))
     (?* . (lambda (file)
             (and (file-regular-p file)
                  (not (file-symlink-p file))
@@ -161,6 +161,7 @@ eshell-predicate-help-string
 
 OWNERSHIP:
   U               owned by effective uid
+  G               owned by effective gid
   u(UID|\\='user\\=')   owned by UID/user
   g(GID|\\='group\\=')  owned by GID/group
 
diff --git a/test/lisp/eshell/em-pred-tests.el b/test/lisp/eshell/em-pred-tests.el
index 74dad9f8b8..fbf8945215 100644
--- a/test/lisp/eshell/em-pred-tests.el
+++ b/test/lisp/eshell/em-pred-tests.el
@@ -225,6 +225,14 @@ em-pred-test/predicate-effective-uid
         (should (equal (eshell-eval-predicate files "U")
                        '("/fake/uid=1")))))))
 
+(ert-deftest em-pred-test/predicate-effective-gid ()
+  "Test that \"G\" matches files owned by the effective GID."
+  (eshell-with-file-attributes-from-name
+    (cl-letf (((symbol-function 'group-gid) (lambda () 1)))
+      (let ((files '("/fake/gid=1" "/fake/gid=2")))
+        (should (equal (eshell-eval-predicate files "G")
+                       '("/fake/gid=1")))))))
+
 (ert-deftest em-pred-test/predicate-links ()
   "Test that \"l\" filters by number of links."
   (eshell-with-file-attributes-from-name
-- 
2.25.1