Filter packages by name in list-packages. (Bug#36981)

* lisp/emacs-lisp/package.el (package-menu-filter-by-name): New
function to filter packages by name.
(package-menu-clear-filter): New function to clear applied filters.
(package-menu-filter-by-keyword): Rename function from
package-menu-filter.
(package-menu--generate): Don't change 'q' binding anymore.
(package-menu-mode-map): Bind '/ n' to package-menu-filter-by-name, '/
k' to package-menu-filter-by-keyword and '/ /' to
package-menu-clear-filter.
(package-menu-mode-menu): Update menu entries for the three functions.
* test/lisp/emacs-lisp/package-tests.el (package-test-list-filter-by-name)
(package-test-list-clear-filter): New tests.
* doc/emacs/package.texi: Document usage of
package-menu-filter-by-name, package-menu-clear-filter and update
reference to package-menu-filter-by-keyword.
* etc/NEWS: Announce changes.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/lisp/emacs-lisp/package-tests.el b/test/lisp/emacs-lisp/package-tests.el
index 0edb81d6a11..8670e6f3fac 100644
--- a/test/lisp/emacs-lisp/package-tests.el
+++ b/test/lisp/emacs-lisp/package-tests.el
@@ -365,6 +365,28 @@ Must called from within a `tar-mode' buffer."
       (should-not (re-search-forward "^\\s-+simple-single\\s-+1.3\\s-+\\(available\\|new\\)" nil t))
       (kill-buffer buf))))
 
+(ert-deftest package-test-list-filter-by-name ()
+  "Ensure package list is filtered correctly by package name."
+  (with-package-test ()
+    (let ((buf (package-list-packages)))
+      (package-menu-filter-by-name "tetris")
+      (goto-char (point-min))
+      (should (re-search-forward "^\\s-+tetris" nil t))
+      (should (= (count-lines (point-min) (point-max)) 1))
+      (kill-buffer buf))))
+
+(ert-deftest package-test-list-clear-filter ()
+  "Ensure package list filter is cleared correctly."
+  (with-package-test ()
+    (let ((buf (package-list-packages)))
+      (let ((num-packages (count-lines (point-min) (point-max))))
+        (should (> num-packages 1))
+        (package-menu-filter-by-name "tetris")
+        (should (= (count-lines (point-min) (point-max)) 1))
+        (package-menu-clear-filter)
+        (should (= (count-lines (point-min) (point-max)) num-packages)))
+      (kill-buffer buf))))
+
 (ert-deftest package-test-update-archives ()
   "Test updating package archives."
   (with-package-test ()