bug#22860: 24.3; hg merge not too functional

bug#22860: 24.3; hg merge not too functional

[Ross Boylan]

C-x v d
put me in version  control dired mode for a mercurial-controlled
directory.
C-x v m then says
Running "hg merge"...
abort: branch 'logit' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)

It doesn't seem there's any way to specify the merge target.
I am not prompted for it, even if using C-u as a prefix.

vc.el says
;; - merge-branch ()
;;
;;   Merge another branch into the current one, prompting for a
;;   location to merge from.
;;

but in vc-hg.el that  does not seem to be the behavior.
This is probably a known problem, since the header on vc-hg.el has
;; - merge (file rev1 rev2)                    NEEDED
This comment remains in the latest git revision.

In GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.7)
 of 2014-03-07 on lamiak, modified by Debian
System Description:	Ubuntu 14.04.4 LTS

Configured using:
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 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var/lib' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 '--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.3/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.3/site-lisp:/usr/share/emacs/site-lisp'
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 '--with-x-toolkit=gtk3' '--with-toolkit-scroll-bars'
 'build_alias=x86_64-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
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 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
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  tool-bar-mode: t
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  buffer-read-only: t
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  transient-mark-mode: t

Recent input:
G M C-g # # SPC n e w SPC d a y RET d a t e ; SPC h 
g SPC h e a d s RET C-x v d RET C-x v m C-u C-x v m 
C-h c C-x v m C-h f v c - m e r g e RET C-x o ESC O 
B ESC O C ESC O C RET ESC [ 6 ~ ESC [ 5 ~ C-s v c - 
m e r g e C-s - b C-s C-s C-s C-s C-s C-g C-g ESC O 
A ESC O A ESC O A ESC O A ESC O A ESC O A ESC O A ESC 
O A ESC O A ESC O A ESC O C ESC O C ESC O C ESC O C 
ESC O C ESC O C ESC O C C-r v c - c a l l - b a c k 
e n d C-r C-r C-r C-r C-r RET C-r d e f u n SPC v c 
- c a l l C-s C-s C-s ESC < C-s v c - c a l l - b a 
c k e n d C-s C-s C-s C-s C-s C-s C-s C-s C-s C-s C-s 
C-s ESC < ESC [ 6 ~ ESC [ 6 ~ ESC [ 6 ~ ESC [ 6 ~ ESC 
[ 6 ~ C-x C-f v c - h g TAB RET C-s d e f u n SPC m 
e r DEL DEL DEL v c - m e r g e RET C-s m e r g e - 
b r ESC < ESC [ 6 ~ ESC [ 5 ~ ESC x r e p o r t - b 
u g RET

Recent messages:
uncompressing vc.el.gz...done
Note: file is write protected
Quit
Mark saved where search started [2 times]
Mark set
Mark saved where search started
Mark set
uncompressing vc-hg.el.gz...done
Note: file is write protected
Mark saved where search started [2 times]

Load-path shadows:
/usr/share/emacs/24.3/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup

Features:
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server jka-compr info vc-hg ido ess-toolbar ess-mouse mouseme thingatpt
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czech european ethiopic indian cyrillic chinese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer loaddefs button faces
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env code-pages mule custom widget hashtable-print-readable backquote
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bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Andrii Kolomoiets]

[-- Attachment #1: Type: text/plain, Size: 26 bytes --]

Hi,

See attached patch.


[-- Attachment #2: 0001-vc-hg-prompt-for-branch-to-merge.patch --]
[-- Type: application/octet-stream, Size: 2614 bytes --]

From 52af9a5a85aadb305035139fab2a962abb4eead0 Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 23 Nov 2019 18:43:47 +0200
Subject: [PATCH] vc-hg: prompt for branch to merge

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for branch to merge.
(vc-hg-revision-table): Use branches and tags as competion candidates.

* etc/NEWS Mention changes of vc-hg.el

This fixes bug#22860

diff --git a/etc/NEWS b/etc/NEWS
index ad349b1613..abd2c616bd 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -933,6 +933,11 @@ values.
 The 'C-x v h' command now works in buffers that visit files controlled
 by Hg.

+*** The Hg (Mercurial) back-end now prompt for branch to merge.
+
+*** The Hg (Mercurial) back-end now use tag and branch names instead of
+revision numbers as completion candidates on reading revision.
+
 +++
 *** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
 and compares their entire trees.
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index 17d38fa400..b6cb315c1b 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -564,7 +564,8 @@ vc-hg-expanded-log-entry
 (defun vc-hg-revision-table (files)
   (let ((default-directory (file-name-directory (car files))))
     (with-temp-buffer
-      (vc-hg-command t nil files "log" "--template" "{rev} ")
+      (vc-hg-command t nil nil "branches" "-q")
+      (vc-hg-command t nil nil "tags" "-q")
       (split-string
        (buffer-substring-no-properties (point-min) (point-max))))))

@@ -1483,13 +1484,16 @@ vc-hg-push
   (vc-hg--pushpull "push" prompt nil (called-interactively-p 'interactive)))

 (defun vc-hg-merge-branch ()
-  "Merge incoming changes into the current working directory.
+  "Prompts for branch and merge it into the current branch.
 This runs the command \"hg merge\"."
   (let* ((root (vc-hg-root default-directory))
 	 (buffer (format "*vc-hg : %s*" (expand-file-name root)))
          ;; Disable pager.
-         (process-environment (cons "HGPLAIN=1" process-environment)))
-    (apply 'vc-do-async-command buffer root vc-hg-program '("--config" "ui.report_untrusted=0" "merge"))
+         (process-environment (cons "HGPLAIN=1" process-environment))
+         (branch (vc-read-revision "Merge from branch: ")))
+    (apply 'vc-do-async-command buffer root vc-hg-program
+           (append '("--config" "ui.report_untrusted=0" "merge")
+                   (unless (string= branch "") (list branch))))
     (with-current-buffer buffer (vc-run-delayed (vc-compilation-mode 'hg)))
     (vc-set-async-update buffer)))

--
2.15.1

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> From: Andrii Kolomoiets <andreyk.mad@gmail.com>
> Date: Sat, 23 Nov 2019 20:12:27 +0200
> 
> See attached patch.

Thanks.

> +*** The Hg (Mercurial) back-end now use tag and branch names instead of
> +revision numbers as completion candidates on reading revision.

Why "instead of revision numbers"? it sounds like a backward
incompatible change.  Can't we use both revision numbers and
branch/tag names?

>  (defun vc-hg-merge-branch ()
> -  "Merge incoming changes into the current working directory.
> +  "Prompts for branch and merge it into the current branch.

"Prompt", not "prompts", for consistency with how we word our doc
strings for functions.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Dmitry Gutov]

On 23.11.2019 20:34, Eli Zaretskii wrote:
>> +*** The Hg (Mercurial) back-end now use tag and branch names instead of
>> +revision numbers as completion candidates on reading revision.
> Why "instead of revision numbers"? it sounds like a backward
> incompatible change.  Can't we use both revision numbers and
> branch/tag names?

It's a good change. You could see it in the patch I send yesterday too.

The user doesn't need completion for revisions, but they can still input 
them. And for a large repository, listing all revisions is hella slow.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> Cc: 22860@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Sat, 23 Nov 2019 20:46:48 +0200
> 
> On 23.11.2019 20:34, Eli Zaretskii wrote:
> >> +*** The Hg (Mercurial) back-end now use tag and branch names instead of
> >> +revision numbers as completion candidates on reading revision.
> > Why "instead of revision numbers"? it sounds like a backward
> > incompatible change.  Can't we use both revision numbers and
> > branch/tag names?
> 
> It's a good change. You could see it in the patch I send yesterday too.
> 
> The user doesn't need completion for revisions, but they can still input 
> them. And for a large repository, listing all revisions is hella slow.

Do we perhaps want an option to get back the old behavior?

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Dmitry Gutov]

On 23.11.2019 20:51, Eli Zaretskii wrote:
> Do we perhaps want an option to get back the old behavior?

I don't think so. There's little point in completion for numbers.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Andrii Kolomoiets]

[-- Attachment #1: Type: text/plain, Size: 901 bytes --]

On 23 Nov 2019, at 20:34, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> +*** The Hg (Mercurial) back-end now use tag and branch names instead of
>> +revision numbers as completion candidates on reading revision.
> 
> Why "instead of revision numbers"? it sounds like a backward
> incompatible change.  Can't we use both revision numbers and
> branch/tag names?

You are right, it's backward incompatible. And yes, revision numbers can
be used with branch/tag names. But they should not. It was big surprise
for me to see numbers from 0 to 116K as completion candidates on
vc-retrieve-tag. IMO revision numbers are useles in completions.

>> (defun vc-hg-merge-branch ()
>> -  "Merge incoming changes into the current working directory.
>> +  "Prompts for branch and merge it into the current branch.
> 
> "Prompt", not "prompts", for consistency with how we word our doc
> strings for functions.

Fixed.


[-- Attachment #2: 0001-vc-hg-prompt-for-branch-to-merge.patch --]
[-- Type: application/octet-stream, Size: 2613 bytes --]

From 52af9a5a85aadb305035139fab2a962abb4eead0 Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 23 Nov 2019 18:43:47 +0200
Subject: [PATCH] vc-hg: prompt for branch to merge

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for branch to merge.
(vc-hg-revision-table): Use branches and tags as competion candidates.

* etc/NEWS Mention changes of vc-hg.el

This fixes bug#22860

diff --git a/etc/NEWS b/etc/NEWS
index ad349b1613..abd2c616bd 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -933,6 +933,11 @@ values.
 The 'C-x v h' command now works in buffers that visit files controlled
 by Hg.

+*** The Hg (Mercurial) back-end now prompt for branch to merge.
+
+*** The Hg (Mercurial) back-end now use tag and branch names instead of
+revision numbers as completion candidates on reading revision.
+
 +++
 *** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
 and compares their entire trees.
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index 17d38fa400..b6cb315c1b 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -564,7 +564,8 @@ vc-hg-expanded-log-entry
 (defun vc-hg-revision-table (files)
   (let ((default-directory (file-name-directory (car files))))
     (with-temp-buffer
-      (vc-hg-command t nil files "log" "--template" "{rev} ")
+      (vc-hg-command t nil nil "branches" "-q")
+      (vc-hg-command t nil nil "tags" "-q")
       (split-string
        (buffer-substring-no-properties (point-min) (point-max))))))

@@ -1483,12 +1484,15 @@ vc-hg-push
   (vc-hg--pushpull "push" prompt nil (called-interactively-p 'interactive)))

 (defun vc-hg-merge-branch ()
-  "Merge incoming changes into the current working directory.
+  "Prompt for branch and merge it into the current branch.
 This runs the command \"hg merge\"."
   (let* ((root (vc-hg-root default-directory))
 	 (buffer (format "*vc-hg : %s*" (expand-file-name root)))
          ;; Disable pager.
-         (process-environment (cons "HGPLAIN=1" process-environment)))
-    (apply 'vc-do-async-command buffer root vc-hg-program '("--config" "ui.report_untrusted=0" "merge"))
+         (process-environment (cons "HGPLAIN=1" process-environment))
+         (branch (vc-read-revision "Merge from branch: ")))
+    (apply 'vc-do-async-command buffer root vc-hg-program
+           (append '("--config" "ui.report_untrusted=0" "merge")
+                   (unless (string= branch "") (list branch))))
     (with-current-buffer buffer (vc-run-delayed (vc-compilation-mode 'hg)))
     (vc-set-async-update buffer)))

--
2.15.1

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> From: Andrii Kolomoiets <andreyk.mad@gmail.com>
> Date: Sat, 23 Nov 2019 20:51:28 +0200
> Cc: 22860@debbugs.gnu.org
> 
> +*** The Hg (Mercurial) back-end now prompt for branch to merge.
                                       ^^^^^^
"Prompts" is more correct English.

Also, I'm guessing this is about the "C-x v m" command, not in
general?  The NEWS item should say so.

And finally, "C-x v m" is described in the user manual, but it only
talks about Git and Bazaar; I thin we should mention Mercurial there
as well.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Andrii Kolomoiets]

[-- Attachment #1: Type: text/plain, Size: 614 bytes --]

On 23 Nov 2019, at 21:01, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Andrii Kolomoiets <andreyk.mad@gmail.com>
>> Date: Sat, 23 Nov 2019 20:51:28 +0200
>> Cc: 22860@debbugs.gnu.org
>> 
>> +*** The Hg (Mercurial) back-end now prompt for branch to merge.
>                                       ^^^^^^
> "Prompts" is more correct English.
> 
> Also, I'm guessing this is about the "C-x v m" command, not in
> general?  The NEWS item should say so.
> 
> And finally, "C-x v m" is described in the user manual, but it only
> talks about Git and Bazaar; I thin we should mention Mercurial there
> as well.

Done.


[-- Attachment #2: 0001-vc-hg-prompt-for-branch-to-merge.patch --]
[-- Type: application/octet-stream, Size: 4277 bytes --]

From 7fe0f7cb6cd15dfb307601eb126f1b1b72b073bd Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 23 Nov 2019 18:43:47 +0200
Subject: [PATCH] vc-hg: prompt for branch to merge

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for branch to merge.
(vc-hg-revision-table): Use branches and tags as competion candidates.

* etc/NEWS Mention changes of vc-hg.el

* doc/emacs/maintaining.texi (Switching Branches): Mention 'hg update'
command.
(Merging): Mention 'hg merge' command.

This fixes bug#22860

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 33a1ec0be0..6e25461507 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -1427,7 +1427,9 @@ Switching Branches
 working tree to match the branch you switch to.  Bazaar also supports
 co-located branches, in which case the @command{bzr switch} command
 will switch branches in the current directory.  With Subversion, you
-switch to another branch using the @command{svn switch} command.
+switch to another branch using the @command{svn switch} command.  On
+Mercurial, command @command{hg update} is used to swith to another
+branch.
 
   The VC command to switch to another branch in the current directory
 is @kbd{C-x v r @var{branch-name} @key{RET}} (@code{vc-retrieve-tag}).
@@ -1542,8 +1544,9 @@ Merging
 the exact arguments to pass to @command{bzr merge}, offering a
 sensible default if possible.  On Git, this prompts for the name of a
 branch to merge from, with completion (based on the branch names known
-to the current repository).  The output from running the merge command
-is shown in a separate buffer.
+to the current repository).  On Mercurial, this prompts for argument to
+pass to @command{hg merge}, with branch and tag names completion. The
+output from running the merge command is shown in a separate buffer.
 
   On a centralized version control system like CVS, @kbd{C-x v m}
 prompts for a branch ID, or a pair of revision IDs (@pxref{Switching
diff --git a/etc/NEWS b/etc/NEWS
index ad349b1613..462b0ef6a2 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -933,6 +933,12 @@ values.
 The 'C-x v h' command now works in buffers that visit files controlled
 by Hg.
 
+*** The Hg (Mercurial) back-end now prompts for revision to merge on
+'C-x v m' ('vc-merge').
+
+*** The Hg (Mercurial) back-end now use tag and branch names instead of
+revision numbers as completion candidates on reading revision.
+
 +++
 *** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
 and compares their entire trees.
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index 17d38fa400..3a52e699ec 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -564,7 +564,8 @@ vc-hg-expanded-log-entry
 (defun vc-hg-revision-table (files)
   (let ((default-directory (file-name-directory (car files))))
     (with-temp-buffer
-      (vc-hg-command t nil files "log" "--template" "{rev} ")
+      (vc-hg-command t nil nil "branches" "-q")
+      (vc-hg-command t nil nil "tags" "-q")
       (split-string
        (buffer-substring-no-properties (point-min) (point-max))))))
 
@@ -1483,13 +1484,16 @@ vc-hg-push
   (vc-hg--pushpull "push" prompt nil (called-interactively-p 'interactive)))
 
 (defun vc-hg-merge-branch ()
-  "Merge incoming changes into the current working directory.
+  "Prompt for revision and merge it into working directory.
 This runs the command \"hg merge\"."
   (let* ((root (vc-hg-root default-directory))
 	 (buffer (format "*vc-hg : %s*" (expand-file-name root)))
          ;; Disable pager.
-         (process-environment (cons "HGPLAIN=1" process-environment)))
-    (apply 'vc-do-async-command buffer root vc-hg-program '("--config" "ui.report_untrusted=0" "merge"))
+         (process-environment (cons "HGPLAIN=1" process-environment))
+         (branch (vc-read-revision "Merge from branch: ")))
+    (apply 'vc-do-async-command buffer root vc-hg-program
+           (append '("--config" "ui.report_untrusted=0" "merge")
+                   (unless (string= branch "") (list branch))))
     (with-current-buffer buffer (vc-run-delayed (vc-compilation-mode 'hg)))
     (vc-set-async-update buffer)))
 
-- 
2.15.1

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Dmitry Gutov]

Hi Andrii,

The patch looks good to me. Some minor nits:

On 23.11.2019 22:15, Andrii Kolomoiets wrote:
> * etc/NEWS Mention changes of vc-hg.el

It's missing a colon after "NEWS" (":").

> +to the current repository).  On Mercurial, this prompts for argument to
> +pass to @command{hg merge}, with branch and tag names completion. The
> +output from running the merge command is shown in a separate buffer.

The fact that there is completion here is incidental. I'd omit that from 
this particular place in the manual.

> +*** The Hg (Mercurial) back-end now prompts for revision to merge on
> +'C-x v m' ('vc-merge').

Branch or revision? I understand that in practice the difference is 
minimal, but we should pick one or the other wording and use it 
consistently. Here, in the functions' docstrings, and in the prompt 
string as well.

I'd prefer "branch" since it's usually what someone merges, but saying 
"revision" everywhere should also be okay.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Andrii Kolomoiets]

[-- Attachment #1: Type: text/plain, Size: 1584 bytes --]

On 25 Nov 2019, at 16:41, Dmitry Gutov <dgutov@yandex.ru> wrote:
> 
> Hi Andrii,

Hi Dmitry,

> On 23.11.2019 22:15, Andrii Kolomoiets wrote:
>> * etc/NEWS Mention changes of vc-hg.el
> 
> It's missing a colon after "NEWS" (":").

Fixed.

>> +to the current repository).  On Mercurial, this prompts for argument to
>> +pass to @command{hg merge}, with branch and tag names completion. The
>> +output from running the merge command is shown in a separate buffer.
> 
> The fact that there is completion here is incidental. I'd omit that from this particular place in the manual.

Fixed. In my defense, that sentence was modelled after git's one :)

>> +*** The Hg (Mercurial) back-end now prompts for revision to merge on
>> +'C-x v m' ('vc-merge').
> 
> Branch or revision? I understand that in practice the difference is minimal, but we should pick one or the other wording and use it consistently. Here, in the functions' docstrings, and in the prompt string as well.
> 
> I'd prefer "branch" since it's usually what someone merges, but saying "revision" everywhere should also be okay.

Initially it was "branch". But vc-hg doesn't work with branches at the moment. Even vc-create-tag creates bookmark instead of branch, see bug#17586 (but let's leave it to the future patches).
Besides that, "revision" is used in the "merge" command manual. "revision" can mean a lot of things, see "hg help revisions". Thats why I decide to replace "branch" with "revision".

Please see attached patch. Besides fixes, "bookmarks" added to completion candidates.


[-- Attachment #2: 0001-vc-hg-prompt-for-branch-to-merge.patch --]
[-- Type: application/octet-stream, Size: 4313 bytes --]

From cf764cbe233eb162e3afa9d3f25acc96875e3f8e Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 23 Nov 2019 18:43:47 +0200
Subject: [PATCH] vc-hg: prompt for branch to merge

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for revision to merge.
(vc-hg-revision-table): Use branches, tags and bookmarks as competion
candidates.

* etc/NEWS: Mention changes of vc-hg.el

* doc/emacs/maintaining.texi (Switching Branches): Mention 'hg update'
command.
(Merging): Mention 'hg merge' command.

This fixes bug#22860

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 33a1ec0be0..67072b5e92 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -1427,7 +1427,9 @@ Switching Branches
 working tree to match the branch you switch to.  Bazaar also supports
 co-located branches, in which case the @command{bzr switch} command
 will switch branches in the current directory.  With Subversion, you
-switch to another branch using the @command{svn switch} command.
+switch to another branch using the @command{svn switch} command.  On
+Mercurial, command @command{hg update} is used to swith to another
+branch.
 
   The VC command to switch to another branch in the current directory
 is @kbd{C-x v r @var{branch-name} @key{RET}} (@code{vc-retrieve-tag}).
@@ -1542,8 +1544,9 @@ Merging
 the exact arguments to pass to @command{bzr merge}, offering a
 sensible default if possible.  On Git, this prompts for the name of a
 branch to merge from, with completion (based on the branch names known
-to the current repository).  The output from running the merge command
-is shown in a separate buffer.
+to the current repository).  On Mercurial, this prompts for argument to
+pass to @command{hg merge}. The output from running the merge command is
+shown in a separate buffer.
 
   On a centralized version control system like CVS, @kbd{C-x v m}
 prompts for a branch ID, or a pair of revision IDs (@pxref{Switching
diff --git a/etc/NEWS b/etc/NEWS
index ad349b1613..4a718e1357 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -933,6 +933,12 @@ values.
 The 'C-x v h' command now works in buffers that visit files controlled
 by Hg.
 
+*** The Hg (Mercurial) back-end now prompts for revision to merge on
+'C-x v m' ('vc-merge').
+
+*** The Hg (Mercurial) back-end now use tags, branches and bookmarks
+instead of revision numbers as completion candidates on reading revision.
+
 +++
 *** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
 and compares their entire trees.
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index 17d38fa400..4d45ea1ccc 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -564,7 +564,9 @@ vc-hg-expanded-log-entry
 (defun vc-hg-revision-table (files)
   (let ((default-directory (file-name-directory (car files))))
     (with-temp-buffer
-      (vc-hg-command t nil files "log" "--template" "{rev} ")
+      (vc-hg-command t nil nil "branches" "-q")
+      (vc-hg-command t nil nil "bookmarks" "-q")
+      (vc-hg-command t nil nil "tags" "-q")
       (split-string
        (buffer-substring-no-properties (point-min) (point-max))))))
 
@@ -1483,13 +1485,16 @@ vc-hg-push
   (vc-hg--pushpull "push" prompt nil (called-interactively-p 'interactive)))
 
 (defun vc-hg-merge-branch ()
-  "Merge incoming changes into the current working directory.
+  "Prompt for revision and merge it into working directory.
 This runs the command \"hg merge\"."
   (let* ((root (vc-hg-root default-directory))
 	 (buffer (format "*vc-hg : %s*" (expand-file-name root)))
          ;; Disable pager.
-         (process-environment (cons "HGPLAIN=1" process-environment)))
-    (apply 'vc-do-async-command buffer root vc-hg-program '("--config" "ui.report_untrusted=0" "merge"))
+         (process-environment (cons "HGPLAIN=1" process-environment))
+         (branch (vc-read-revision "Revision to merge: ")))
+    (apply 'vc-do-async-command buffer root vc-hg-program
+           (append '("--config" "ui.report_untrusted=0" "merge")
+                   (unless (string= branch "") (list branch))))
     (with-current-buffer buffer (vc-run-delayed (vc-compilation-mode 'hg)))
     (vc-set-async-update buffer)))
 
-- 
2.15.1

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Dmitry Gutov]

On 25.11.2019 23:55, Andrii Kolomoiets wrote:

>> It's missing a colon after "NEWS" (":").
> 
> Fixed.

Thank you.

>>> +to the current repository).  On Mercurial, this prompts for argument to
>>> +pass to @command{hg merge}, with branch and tag names completion. The
>>> +output from running the merge command is shown in a separate buffer.
>>
>> The fact that there is completion here is incidental. I'd omit that from this particular place in the manual.
> 
> Fixed. In my defense, that sentence was modelled after git's one :)

In that case, my opinion might conflict with Eli's (sorry). So I'll 
leave the final review to him.

>>> +*** The Hg (Mercurial) back-end now prompts for revision to merge on
>>> +'C-x v m' ('vc-merge').
>>
>> Branch or revision? I understand that in practice the difference is minimal, but we should pick one or the other wording and use it consistently. Here, in the functions' docstrings, and in the prompt string as well.
>>
>> I'd prefer "branch" since it's usually what someone merges, but saying "revision" everywhere should also be okay.
> 
> Initially it was "branch". But vc-hg doesn't work with branches at the moment. Even vc-create-tag creates bookmark instead of branch, see bug#17586 (but let's leave it to the future patches).

Sure. It really creates (if branchp "bookmark" "tag"), but I'm not clear 
on the difference between branches and bookmarks in Mercurial anyway.

> Besides that, "revision" is used in the "merge" command manual. "revision" can mean a lot of things, see "hg help revisions". Thats why I decide to replace "branch" with "revision".

Ok, thank you. I think that "meaning lots of things" can correspond to 
Git's notion of "ref".

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 26 Nov 2019 00:57:59 +0200
> Cc: 22860@debbugs.gnu.org
> 
> >>> +to the current repository).  On Mercurial, this prompts for argument to
> >>> +pass to @command{hg merge}, with branch and tag names completion. The
> >>> +output from running the merge command is shown in a separate buffer.
> >>
> >> The fact that there is completion here is incidental. I'd omit that from this particular place in the manual.
> > 
> > Fixed. In my defense, that sentence was modelled after git's one :)
> 
> In that case, my opinion might conflict with Eli's (sorry). So I'll 
> leave the final review to him.

If it's important to mention completion, we should do that for all
back-ends that support this command.  Right now, the text mentions the
default offered by the prompt for Bazaar, but with Git and Mercurial
it mentions completion.  Don't the latter two offer sensible defaults
as well?  If they do, let's mention them; if they don't, perhaps its
better to say something like

  Git and Mercurial don't offer a default revision, but they provide
  completion to help you specify the revision.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> From: Andrii Kolomoiets <andreyk.mad@gmail.com>
> Date: Mon, 25 Nov 2019 23:55:16 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>,
>  22860@debbugs.gnu.org
> 
> --- a/doc/emacs/maintaining.texi
> +++ b/doc/emacs/maintaining.texi
> @@ -1427,7 +1427,9 @@ Switching Branches
>  working tree to match the branch you switch to.  Bazaar also supports
>  co-located branches, in which case the @command{bzr switch} command
>  will switch branches in the current directory.  With Subversion, you
> -switch to another branch using the @command{svn switch} command.
> +switch to another branch using the @command{svn switch} command.  On
> +Mercurial, command @command{hg update} is used to swith to another
> +branch.

I suggest "with Mercurial", not "on Mercurial".

> @@ -1542,8 +1544,9 @@ Merging
>  the exact arguments to pass to @command{bzr merge}, offering a
>  sensible default if possible.  On Git, this prompts for the name of a
>  branch to merge from, with completion (based on the branch names known
> -to the current repository).  The output from running the merge command
> -is shown in a separate buffer.
> +to the current repository).  On Mercurial, this prompts for argument to

Likewise here.  (Yes, the Git sentence is also wrong.)

> +pass to @command{hg merge}. The output from running the merge command is
                             ^^
Two spaces between sentences, please.

> +*** The Hg (Mercurial) back-end now prompts for revision to merge on
> +'C-x v m' ('vc-merge').                                           ^^
    ^^^^^^^^
"when you invoke 'C-x v m'"

> +*** The Hg (Mercurial) back-end now use tags, branches and bookmarks
> +instead of revision numbers as completion candidates on reading revision.
                                                        ^^^^^^^^^^^^^^^^^^^
"when it prompts for a revision"

Thanks.

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Andrii Kolomoiets]

[-- Attachment #1: Type: text/plain, Size: 279 bytes --]

On 26 Nov 2019, at 20:16, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> I suggest "with Mercurial", not "on Mercurial".
> 
> Two spaces between sentences, please.
> 
> "when you invoke 'C-x v m'"
> 
> "when it prompts for a revision"

All issues are fixed. Please see updated patch.


[-- Attachment #2: 0001-vc-hg-prompt-for-branch-to-merge.patch --]
[-- Type: application/octet-stream, Size: 4549 bytes --]

From 50c9bb40f1fb859cded12eaccf56835f3a90eea3 Mon Sep 17 00:00:00 2001
From: Andrii Kolomoiets <andreyk.mad@gmail.com>
Date: Sat, 23 Nov 2019 18:43:47 +0200
Subject: [PATCH] vc-hg: prompt for branch to merge

* lisp/vc/vc-hg.el (vc-hg-merge-branch): Prompt for revision to merge.
(vc-hg-revision-table): Use branches, tags and bookmarks as competion
candidates.

* etc/NEWS: Mention changes of vc-hg.el

* doc/emacs/maintaining.texi (Switching Branches): Mention 'hg update'
command.
(Merging): Mention 'hg merge' command.

This fixes bug#22860
---
 doc/emacs/maintaining.texi |  9 ++++++---
 etc/NEWS                   |  9 +++++++++
 lisp/vc/vc-hg.el           | 13 +++++++++----
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 33a1ec0be0..f48173ae91 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -1427,7 +1427,9 @@ Switching Branches
 working tree to match the branch you switch to.  Bazaar also supports
 co-located branches, in which case the @command{bzr switch} command
 will switch branches in the current directory.  With Subversion, you
-switch to another branch using the @command{svn switch} command.
+switch to another branch using the @command{svn switch} command.  With
+Mercurial, command @command{hg update} is used to swith to another
+branch.
 
   The VC command to switch to another branch in the current directory
 is @kbd{C-x v r @var{branch-name} @key{RET}} (@code{vc-retrieve-tag}).
@@ -1542,8 +1544,9 @@ Merging
 the exact arguments to pass to @command{bzr merge}, offering a
 sensible default if possible.  On Git, this prompts for the name of a
 branch to merge from, with completion (based on the branch names known
-to the current repository).  The output from running the merge command
-is shown in a separate buffer.
+to the current repository).  With Mercurial, this prompts for argument
+to pass to @command{hg merge}.  The output from running the merge
+command is shown in a separate buffer.
 
   On a centralized version control system like CVS, @kbd{C-x v m}
 prompts for a branch ID, or a pair of revision IDs (@pxref{Switching
diff --git a/etc/NEWS b/etc/NEWS
index ad349b1613..bb5c54dabe 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -933,6 +933,15 @@ values.
 The 'C-x v h' command now works in buffers that visit files controlled
 by Hg.
 
++++
+*** The Hg (Mercurial) back-end now prompts for revision to merge when
+you invoke 'C-x v m' ('vc-merge').
+
+---
+*** The Hg (Mercurial) back-end now use tags, branches and bookmarks
+instead of revision numbers as completion candidates when it prompts
+for a revision.
+
 +++
 *** 'C-u C-x v D' ('vc-root-version-diff') prompts for two revisions
 and compares their entire trees.
diff --git a/lisp/vc/vc-hg.el b/lisp/vc/vc-hg.el
index 17d38fa400..4d45ea1ccc 100644
--- a/lisp/vc/vc-hg.el
+++ b/lisp/vc/vc-hg.el
@@ -564,7 +564,9 @@ vc-hg-expanded-log-entry
 (defun vc-hg-revision-table (files)
   (let ((default-directory (file-name-directory (car files))))
     (with-temp-buffer
-      (vc-hg-command t nil files "log" "--template" "{rev} ")
+      (vc-hg-command t nil nil "branches" "-q")
+      (vc-hg-command t nil nil "bookmarks" "-q")
+      (vc-hg-command t nil nil "tags" "-q")
       (split-string
        (buffer-substring-no-properties (point-min) (point-max))))))
 
@@ -1483,13 +1485,16 @@ vc-hg-push
   (vc-hg--pushpull "push" prompt nil (called-interactively-p 'interactive)))
 
 (defun vc-hg-merge-branch ()
-  "Merge incoming changes into the current working directory.
+  "Prompt for revision and merge it into working directory.
 This runs the command \"hg merge\"."
   (let* ((root (vc-hg-root default-directory))
 	 (buffer (format "*vc-hg : %s*" (expand-file-name root)))
          ;; Disable pager.
-         (process-environment (cons "HGPLAIN=1" process-environment)))
-    (apply 'vc-do-async-command buffer root vc-hg-program '("--config" "ui.report_untrusted=0" "merge"))
+         (process-environment (cons "HGPLAIN=1" process-environment))
+         (branch (vc-read-revision "Revision to merge: ")))
+    (apply 'vc-do-async-command buffer root vc-hg-program
+           (append '("--config" "ui.report_untrusted=0" "merge")
+                   (unless (string= branch "") (list branch))))
     (with-current-buffer buffer (vc-run-delayed (vc-compilation-mode 'hg)))
     (vc-set-async-update buffer)))
 
-- 
2.15.1

bug#22860: [PATCH] vc-hg: prompt for branch to merge

[Eli Zaretskii]

> From: Andrii Kolomoiets <andreyk.mad@gmail.com>
> Date: Tue, 26 Nov 2019 21:28:41 +0200
> Cc: Dmitry Gutov <dgutov@yandex.ru>,
>  22860@debbugs.gnu.org
> 
> All issues are fixed. Please see updated patch.

Thanks, installed.