bug#67310: [PATCH] Include the project--list as history when prompting for a project

[Spencer Baugh]

Dmitry Gutov <dmitry@gutov.dev> writes:
> On 22/11/2023 18:18, Spencer Baugh wrote:
>> Dmitry Gutov <dmitry@gutov.dev> writes:
>>> On 21/11/2023 17:17, Spencer Baugh wrote:
>>>>        (if (equal pr-dir dir-choice)
>>>>            (read-directory-name "Select directory: " default-directory nil 
>>>> t)
>>>> +      (project--add-dir pr-dir)
>>>>          pr-dir)))
>>>> ...
>>>>        (if (equal pr-name dir-choice)
>>>>            (read-directory-name "Select directory: " default-directory nil 
>>>> t)
>>>> -      (let ((proj (assoc pr-name choices)))
>>>> -        (if (stringp proj) proj (project-root (cdr proj)))))))
>>>> +      (let* ((proj (assoc pr-name choices))
>>>> +             (root (project-root (cdr proj))))
>>>> +        (project--add-dir root)
>>>> +        root))))
>>>
>>> I think in the (equal pr-dir dir-choice) case we want to add the
>>> directory name entered by the user into the "history" anyway, don't
>>> we?
>> Mmmmaybe?  That would change behavior - currently transient projects
>> don't go into the project--list, and with that change they would.  Do
>> you think they should?
>
> Hmm, maybe not. Anyway, that sentence was supposed to lead into the
> next paragraph anyway.
>
>> I personally never use transient projects so I don't really know how
>> they should behave.
>> 
>>> Though perhaps there's no need to do it here: 'project-current' calls
>>> 'project-remember-project' anyway when maybe-prompt is non-nil.
>>>
>>> So what happens if you drop both of the above 'project--add-dir' calls?
>> project-prompter is also called from project-switch-project, which
>> doesn't call project-remember-project but should also update the history
>> IMO.
>
> I suppose project-switch-project could add a project-remember-project
> call as well?
>
> It's just that until recently it only supported project-related
> commands, and those would invoke (project-current t) right away --
> adding the just-selected root into the list.

Yes, that makes sense, done.  (We only have the project root directory
there, so we still need project--add-dir)

>From 063fe822531d51040be53f47f3dbe35ea77f21be Mon Sep 17 00:00:00 2001
From: Spencer Baugh <sbaugh@janestreet.com>
Date: Mon, 20 Nov 2023 14:38:22 -0500
Subject: [PATCH] Include the project--list as history when prompting for a
 project

The project--list is already ordered such that the most recently used
projects are at the front.  Now we use it as the minibuffer history
when prompting for a project.

To support this, we minorly change the in-memory format of
project--list: Instead of a list of lists, each containing a
project-root, project--list is just a list whose elements are
project-roots.  This lets us pass it directly to add-to-history.  The
persistent format (what's saved in project-list-file) remains the
same.

To avoid savehist from picking up project--list as a minibuffer
history variable and overriding our own persistence mechanism, we
don't pass project--list directly as a history variable, but instead
pass project--dir-history or project--name-history, dynamically-bound
to an appropriate value.  project--dir-history and
project--name-history won't be persisted since they're always unbound
at the top level; but if they are persisted anyway somehow, it won't
affect us.

* lisp/progmodes/project.el (project--list): Update docstring for new
format.
(project-known-project-roots, project-remember-projects-under)
(project--read-project-list, project--write-project-list)
(project-remember-project, project--remove-from-project-list): Support
new format for project--list.
(project--dir-history, project-prompt-project-dir): Pass project--list
as HIST to completing-read.
(project--name-history, project-prompt-project-name): Pass a
preprocessed project--list as HIST to completing-read.
---
 lisp/progmodes/project.el | 99 +++++++++++++++++++++++++--------------
 1 file changed, 64 insertions(+), 35 deletions(-)

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index 95db9d0ef4c..4baa76b932a 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -1678,11 +1678,16 @@ project-list-file
   :group 'project)
 
 (defvar project--list 'unset
-  "List structure containing root directories of known projects.
-With some possible metadata (to be decided).")
+  "List of root directories of known projects.
+
+This is also the minibuffer history variable for
+`project-prompt-project-dir' and `project-prompt-project-name'.")
 
 (defun project--read-project-list ()
-  "Initialize `project--list' using contents of `project-list-file'."
+  "Initialize `project--list' using contents of `project-list-file'.
+
+We expect `project-list-file' to contain a list of one-element
+lists, each containing a project root."
   (let ((filename project-list-file))
     (setq project--list
           (when (file-exists-p filename)
@@ -1691,11 +1696,11 @@ project--read-project-list
               (mapcar
                (lambda (elem)
                  (let ((name (car elem)))
-                   (list (if (file-remote-p name) name
-                           (abbreviate-file-name name)))))
+                   (if (file-remote-p name) name
+                     (abbreviate-file-name name))))
                (read (current-buffer))))))
     (unless (seq-every-p
-             (lambda (elt) (stringp (car-safe elt)))
+             (lambda (elt) (stringp elt))
              project--list)
       (warn "Contents of %s are in wrong format, resetting"
             project-list-file)
@@ -1707,16 +1712,18 @@ project--ensure-read-project-list
     (project--read-project-list)))
 
 (defun project--write-project-list ()
-  "Save `project--list' in `project-list-file'."
+  "Save `project--list' in `project-list-file'.
+
+We store `project--list' as a list of one-element lists, each
+containing a project root."
   (let ((filename project-list-file))
     (with-temp-buffer
       (insert ";;; -*- lisp-data -*-\n")
       (let ((print-length nil)
             (print-level nil))
-        (pp (mapcar (lambda (elem)
-                      (let ((name (car elem)))
-                        (list (if (file-remote-p name) name
-                                (expand-file-name name)))))
+        (pp (mapcar (lambda (name)
+                      (list (if (file-remote-p name) name
+                                (expand-file-name name))))
                     project--list)
             (current-buffer)))
       (write-region nil nil filename nil 'silent))))
@@ -1728,11 +1735,10 @@ project-remember-project
 has changed, and NO-WRITE is nil."
   (project--ensure-read-project-list)
   (let ((dir (abbreviate-file-name (project-root pr))))
-    (unless (equal (caar project--list) dir)
-      (dolist (ent project--list)
-        (when (equal dir (car ent))
-          (setq project--list (delq ent project--list))))
-      (push (list dir) project--list)
+    (unless (equal (car project--list) dir)
+      (let ((history-delete-duplicates t)
+            (history-length t))
+        (add-to-history 'project--list dir))
       (unless no-write
         (project--write-project-list)))))
 
@@ -1743,10 +1749,11 @@ project--remove-from-project-list
 from the list using REPORT-MESSAGE, which is a format string
 passed to `message' as its first argument."
   (project--ensure-read-project-list)
-  (when-let ((ent (assoc (abbreviate-file-name project-root) project--list)))
-    (setq project--list (delq ent project--list))
-    (message report-message project-root)
-    (project--write-project-list)))
+  (let ((dir (abbreviate-file-name project-root)))
+    (when (member dir project--list)
+      (setq project--list (delete dir project--list))
+      (message report-message project-root)
+      (project--write-project-list))))
 
 ;;;###autoload
 (defun project-forget-project (project-root)
@@ -1757,6 +1764,8 @@ project-forget-project
   (project--remove-from-project-list
    project-root "Project `%s' removed from known projects"))
 
+(defvar project--dir-history)
+
 (defun project-prompt-project-dir ()
   "Prompt the user for a directory that is one of the known project roots.
 The project is chosen among projects known from the project list,
@@ -1769,27 +1778,40 @@ project-prompt-project-dir
           ;; completion style).
           (project--file-completion-table
            (append project--list `(,dir-choice))))
+         (project--dir-history project--list)
          (pr-dir ""))
     (while (equal pr-dir "")
       ;; If the user simply pressed RET, do this again until they don't.
-      (setq pr-dir (completing-read "Select project: " choices nil t)))
+      (setq pr-dir
+            (let ((history-add-new-input nil))
+              (completing-read "Select project: " choices nil t nil 
'project--dir-history))))
     (if (equal pr-dir dir-choice)
         (read-directory-name "Select directory: " default-directory nil t)
+      (let q((history-delete-duplicates t)
+            (history-length t))
+        (add-to-history 'project--list pr-dir))
       pr-dir)))
 
+(defvar project--name-history)
+
 (defun project-prompt-project-name ()
   "Prompt the user for a project, by name, that is one of the known project 
roots.
 The project is chosen among projects known from the project list,
 see `project-list-file'.
 It's also possible to enter an arbitrary directory not in the list."
   (let* ((dir-choice "... (choose a dir)")
+         project--name-history
          (choices
           (let (ret)
-            (dolist (dir (project-known-project-roots))
+            ;; Iterate in reverse order so project--name-history is in
+            ;; the correct order.
+            (dolist (dir (reverse project--list))
               ;; we filter out directories that no longer map to a project,
               ;; since they don't have a clean project-name.
-              (if-let (proj (project--find-in-directory dir))
-                  (push (cons (project-name proj) proj) ret)))
+              (when-let (proj (project--find-in-directory dir))
+                (let ((name (project-name proj)))
+                  (push name project--name-history)
+                  (push (cons name proj) ret))))
             ret))
          ;; XXX: Just using this for the category (for the substring
          ;; completion style).
@@ -1798,17 +1820,23 @@ project-prompt-project-name
          (pr-name ""))
     (while (equal pr-name "")
       ;; If the user simply pressed RET, do this again until they don't.
-      (setq pr-name (completing-read "Select project: " table nil t)))
+      (setq pr-name
+            (let ((history-add-new-input nil))
+              (completing-read "Select project: " table nil t nil 
'project--name-history))))
     (if (equal pr-name dir-choice)
         (read-directory-name "Select directory: " default-directory nil t)
-      (let ((proj (assoc pr-name choices)))
-        (if (stringp proj) proj (project-root (cdr proj)))))))
+      (let* ((proj (assoc pr-name choices))
+             (root (project-root (cdr proj))))
+        (let ((history-delete-duplicates t)
+              (history-length t))
+          (add-to-history 'project--list root))
+        root))))
 
 ;;;###autoload
 (defun project-known-project-roots ()
   "Return the list of root directories of all known projects."
   (project--ensure-read-project-list)
-  (mapcar #'car project--list))
+  project--list)
 
 ;;;###autoload
 (defun project-execute-extended-command ()
@@ -1866,13 +1894,14 @@ project-remember-projects-under
 projects."
   (interactive "DDirectory: \nP")
   (project--ensure-read-project-list)
-  (let ((dirs (if recursive
-                  (directory-files-recursively dir "" t)
-                (directory-files dir t)))
-        (known (make-hash-table :size (* 2 (length project--list))
-                                :test #'equal))
-        (count 0))
-    (dolist (project (mapcar #'car project--list))
+  (let* ((dirs (if recursive
+                   (directory-files-recursively dir "" t)
+                 (directory-files dir t)))
+         (roots (project-known-project-roots))
+         (known (make-hash-table :size (* 2 (length roots))
+                                 :test #'equal))
+         (count 0))
+    (dolist (project roots)
       (puthash project t known))
     (dolist (subdir dirs)
       (when-let (((file-directory-p subdir))
-- 
2.39.3