Re: [patch: first impression]

[Dmitry Gutov <dgutov@yandex.ru>]

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On 10.10.2022 18:41, Uwe Brauer wrote:
>>>> "DG" == Dmitry Gutov <dgutov@yandex.ru> writes:
> 
>> On 10.10.2022 17:53, Uwe Brauer wrote:
>>>> On 10.10.2022 09:39, Uwe Brauer wrote:
>>>> Just 'git apply' on top of the latest master.
>>> I have to wait till the BUG I reported is resolved, since otherwise
>>> working with Emacs is an ordeal. However I have given it a try and
>>> it seems, that in mercurial speech,
>>> there is a
>>> hg up tip
>>> Missing, the @ is not on tip (I think called HEAD in git), but on
>>> the changeset (commit) just before.
>>> I have to debug this in order to see what is going on.
>>> The behavior is a bit annoying especially if you continue working
>>> and want to commit again, in which case you might create a new head
>>> (in mercurial speech), if you are not carefully checking the graph
>>> before.
>>> But if you do, your solution is  somehow working.
> 
>> OK. What if our solution also automatically calls `hg up tip` at the
>> end? Should that always work, or would it mess up situations where the
>> user actually wanted to be in that state (head not at tip), and was in
>> that originally?
> 
> Let me think a bit about it and maybe ask other mercurial users on the
> hg mailing list. I would say hg up tip should be ok, since this the
> default behavior anyway

Another option is to use shelving.

See the attached slightly different patch.

>> E.g. if they wanted to "create a new head" using the new method to
>> commit a patch?
> 
> I am not sure you know but in mercurial you could create an anonymous
> head (which is impossible in git, well at least not permanently) but it
> is also strongly avised against doing it, so if you want to do that you
> would create before the commit a named branch, topic or maybe a
> bookmark.

It's probably the same as "detached HEAD" in Git.

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diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index f4a44df3c2..30c1453e42 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -1185,19 +1185,38 @@ vc-hg-log-edit-mode
   "Major mode for editing Hg log messages.
 It is based on `log-edit-mode', and has Hg-specific extensions.")
 
+(defvar vc-hg-patch-string nil)
+
 (defun vc-hg-checkin (files comment &optional _rev)
   "Hg-specific version of `vc-backend-checkin'.
 REV is ignored."
-  (let ((amend-extract-fn
-         (lambda (value)
-           (when (equal value "yes")
-             (list "--amend")))))
-    (apply #'vc-hg-command nil 0 files
-           (nconc (list "commit" "-m")
-                  (log-edit-extract-headers `(("Author" . "--user")
-                                              ("Date" . "--date")
-                                              ("Amend" . ,amend-extract-fn))
-                                            comment)))))
+  (apply #'vc-hg-command nil 0 files
+         (nconc (list "commit"
+                      "-m")
+                (vc-hg--extract-headers comment))))
+
+(defun vc-hg-checkin-patch (patch-string comment)
+  (let ((patch-file (make-temp-file "hg-patch"))
+        (shelf-name (make-temp-name "vc-checkin-patch")))
+    (with-temp-file patch-file
+      (insert patch-string))
+    (vc-hg-command nil t nil "shelve" "-d" shelf-name)
+    (vc-hg-command nil 0 nil "shelve" "-n" shelf-name)
+    (unwind-protect
+        (apply #'vc-hg-command nil 0 nil
+               (nconc (list "import" patch-file "-m")
+                      (vc-hg--extract-headers comment)))
+      (progn
+        (vc-hg-command nil 0 nil "unshelve" "-n" shelf-name)
+        (delete-file patch-file)))))
+
+(defun vc-hg--extract-headers (comment)
+  (log-edit-extract-headers `(("Author" . "--user")
+                              ("Date" . "--date")
+                              ("Amend" . (lambda (value)
+                                           (when (equal value "yes")
+                                             (list "--amend")))))
+                            comment))
 
 (defun vc-hg-find-revision (file rev buffer)
   (let ((coding-system-for-read 'binary)