>From e1562448ca0d95188c4dc9712c8aa4575a5a3bdd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Syn=C3=A1=C4=8Dek?= <jan.synacek@gmail.com>
Date: Wed, 25 May 2022 10:53:55 +0200
Subject: [PATCH] Add new user option project-vc-find-tracked-only

* doc/emacs/maintaining.texi (Projects): Document it.
* lisp/progmodes/project.el (project--vc-list-files): Use it.
---
 doc/emacs/maintaining.texi |  6 ++++--
 etc/NEWS                   |  5 +++++
 lisp/progmodes/project.el  | 16 +++++++++++-----
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 3ddea0ae58..c33b649490 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -1664,8 +1664,10 @@ Projects
 support additional types of projects.
 
   Which files do or don't belong to a project is also determined by
-the project back-end.  For example, the VC back-end doesn't consider
-``ignored'' files (@pxref{VC Ignore}) to be part of the project.
+the project back-end.  For example, the VC back-end only considers
+``ignored'' files (@pxref{VC Ignore}) to be part of the project if
+the value of the variable @code{project-vc-find-tracked-only} is
+non-nil.
 
 @menu
 * Project File Commands::   Commands for handling project files.
diff --git a/etc/NEWS b/etc/NEWS
index 857f300384..abae05749c 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1678,6 +1678,11 @@ Enabling this minor mode turns on hiding header material, like
 'elide-head' does; disabling it shows the header.  The commands
 'elide-head' and 'elide-head-show' are now obsolete.
 
++++
+*** New user option 'project-vc-find-tracked-only'.
+If set to non-nil, 'project-find-file' only considers tracked, that is
+not ignored, files.
+
 ---
 ** The autoarg.el library is now marked obsolete.
 This library provides the 'autoarg-mode' and 'autoarg-kp-mode' minor
diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index 6c50135358..836d6a1574 100644
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -382,6 +382,11 @@ project-vc-merge-submodules
   :package-version '(project . "0.2.0")
   :safe #'booleanp)
 
+(defcustom project-vc-find-tracked-only nil
+  "Non-nil makes `project-find-file' consider only tracked files."
+  :type 'boolean
+  :safe #'booleanp)
+
 ;; FIXME: Using the current approach, major modes are supposed to set
 ;; this variable to a buffer-local value.  So we don't have access to
 ;; the "external roots" of language A from buffers of language B, which
@@ -512,8 +517,9 @@ project--vc-list-files
            (args '("-z"))
            (vc-git-use-literal-pathspecs nil)
            files)
-       ;; Include unregistered.
-       (setq args (append args '("-c" "-o" "--exclude-standard")))
+       (setq args (append args
+                          '("-c" "--exclude-standard")
+                          (unless project-vc-find-tracked-only '("-o"))))
        (when extra-ignores
          (setq args (append args
                             (cons "--"
@@ -565,9 +571,9 @@ project--vc-list-files
        (delete-consecutive-dups files)))
     (`Hg
      (let ((default-directory (expand-file-name (file-name-as-directory dir)))
-           args)
-       ;; Include unregistered.
-       (setq args (nconc args '("-mcardu" "--no-status" "-0")))
+           (args (list (concat "-mcard" (unless project-vc-find-tracked-only "u"))
+                       "--no-status"
+                       "-0")))
        (when extra-ignores
          (setq args (nconc args
                            (mapcan
-- 
2.36.1