master aa486801704: Fix VC mode-line indication for registerd but ignored files

[Eli Zaretskii]

branch: master
commit aa4868017043e60c0875e40e0a67ac1365a477b0
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix VC mode-line indication for registerd but ignored files
    
    * lisp/vc/vc-hooks.el (vc-ignored-state): New face.
    (vc-default-mode-line-string): Add special indication and tooltip
    for files that are registered, but also ignored.  See
    https://lists.gnu.org/archive/html/emacs-devel/2023-09/msg00006.html
    for the details of the use case.
    
    * doc/emacs/maintaining.texi (VC Mode Line): Mention the
    additional meaning of '!' in the VC status mode-line display.
---
 doc/emacs/maintaining.texi | 7 ++++---
 lisp/vc/vc-hooks.el        | 9 +++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 2dad70d3d13..2785ccb5109 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -447,9 +447,10 @@ merge-based version control system, a @samp{-} character 
indicates
 that the work file is unmodified, and @samp{:} indicates that it has
 been modified.  @samp{!} indicates that the file contains conflicts as
 result of a recent merge operation (@pxref{Merging}), or that the file
-was removed from the version control.  Finally, @samp{?} means that
-the file is under version control, but is missing from the working
-tree.
+was removed from the version control, or that it is versioned but also
+@dfn{ignored}, something that usually should not happen (@pxref{VC
+Ignore}).  Finally, @samp{?} means that the file is under version
+control, but is missing from the working tree.
 
   In a lock-based system, @samp{-} indicates an unlocked file, and
 @samp{:} a locked file; if the file is locked by another user (for
diff --git a/lisp/vc/vc-hooks.el b/lisp/vc/vc-hooks.el
index e75165ea2e9..a4de0a6e791 100644
--- a/lisp/vc/vc-hooks.el
+++ b/lisp/vc/vc-hooks.el
@@ -87,6 +87,11 @@
   "Face for VC modeline state when the file is edited."
   :version "25.1")
 
+(defface vc-ignored-state
+  '((default :inherit vc-state-base))
+  "Face for VC modeline state when the file is registered, but ignored."
+  :version "30.1")
+
 ;; Customization Variables (the rest is in vc.el)
 
 (defcustom vc-ignore-dir-regexp
@@ -743,6 +748,10 @@ This function assumes that the file is registered."
             (setq state-echo "File tracked by the VC system, but missing from 
the file system")
            (setq face 'vc-missing-state)
             (concat backend-name "?" rev))
+           ((eq state 'ignored)
+            (setq state-echo "File tracked by the VC system, but ignored")
+            (setq face 'vc-ignored-state)
+            (concat backend-name "!" rev))
           (t
            ;; Not just for the 'edited state, but also a fallback
            ;; for all other states.  Think about different symbols