Evolve Tutorial¶
Initial setup¶
This Mercurial configuration example is used for testing.
$ cat >> $HGRCPATH << EOF
> [ui]
> # This is change the default output of log for clear tutorial
> logtemplate ="{node|short} ({phase}): {desc}\n"
> [diff]
> # use "git" diff format, clearer and smarter format
> git = 1
> EOF
$ hg init local
$ cat >> local/.hg/hgrc << EOF
> [paths]
> remote = ../remote
> other = ../other
> [ui]
> user = Babar the King
> EOF
$ hg init remote
$ cat >> remote/.hg/hgrc << EOF
> [paths]
> local = ../local
> [ui]
> user = Celestine the Queen
> EOF
$ hg init other
$ cat >> other/.hg/hgrc << EOF
> [ui]
> user = Princess Flore
> EOF
This tutorial uses the following configuration for Mercurial:
A compact log template with phase data:
$ hg showconfig ui | grep log
ui.logtemplate="{node|short} ({phase}): {desc}\n"
Improved git format diff:
$ hg showconfig diff
diff.git=1
And of course, we enable the experimental extensions for mutable history:
$ cat >> $HGRCPATH <<EOF
> [extensions]
> evolve = $TESTDIR/../hgext3rd/evolve/
> # enabling rebase is also needed for now
> rebase =
> EOF
Single Developer Usage¶
This tutorial shows how to use evolution to rewrite history locally.
Fixing mistake with hg amend¶
We are versioning a shopping list
$ cd local
$ cat >> shopping << EOF
> Spam
> Whizzo butter
> Albatross
> Rat (rather a lot)
> Jugged fish
> Blancmange
> Salmon mousse
> EOF
$ hg commit -A -m "Monthy Python Shopping list"
adding shopping
Its first version is shared with the outside.
$ hg push remote
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
Later I add additional items to my list
$ cat >> shopping << EOF
> Egg
> Sugar
> Vinegar
> Oil
> EOF
$ hg commit -m "adding condiment"
$ cat >> shopping << EOF
> Bananos
> Pear
> Apple
> EOF
$ hg commit -m "adding fruit"
The history is completely linear so far
$ hg log -G
@ 4296f0622469 (draft): adding fruit
|
o 63ae8c44f4b6 (draft): adding condiment
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
But a typo was made in Bananas!
$ hg export tip
# HG changeset patch
# User test
# Date 0 0
# Thu Jan 01 00:00:00 1970 +0000
# Node ID 4296f0622469c1527d5dc020cf72bd7732c44c64
# Parent 63ae8c44f4b6274d5580b4eea41a87623301c3e9
adding fruit
diff --git a/shopping b/shopping
--- a/shopping
+++ b/shopping
@@ -9,3 +9,6 @@
Sugar
Vinegar
Oil
+Bananos
+Pear
+Apple
The faulty changeset is in the “draft” phase because it has not been exchanged with the outside yet. The first one has been exchanged and is “public” (immutable).
$ hg log -G
@ 4296f0622469 (draft): adding fruit
|
o 63ae8c44f4b6 (draft): adding condiment
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Luckily, I can use hg commit –amend to rewrite my faulty changeset!
$ sed -i'' -e s/Bananos/Banana/ shopping
$ hg diff
diff --git a/shopping b/shopping
--- a/shopping
+++ b/shopping
@@ -9,6 +9,6 @@
Sugar
Vinegar
Oil
-Bananos
+Banana
Pear
Apple
$ hg commit --amend
A new changeset with the correct changes replaces the old one.
$ hg log -G
@ 6445b365ad1c (draft): adding fruit
|
o 63ae8c44f4b6 (draft): adding condiment
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
$ hg export tip
# HG changeset patch
# User test
# Date 0 0
# Thu Jan 01 00:00:00 1970 +0000
# Node ID 6445b365ad1c4905e7a120e45242d9f4b51ec48f
# Parent 63ae8c44f4b6274d5580b4eea41a87623301c3e9
adding fruit
diff --git a/shopping b/shopping
--- a/shopping
+++ b/shopping
@@ -9,3 +9,6 @@
Sugar
Vinegar
Oil
+Banana
+Pear
+Apple
Getting rid of branchy history¶
While I was working on my list, someone made a change remotely.
$ cd ../remote
$ hg up -q
$ sed -i'' -e 's/Spam/Spam Spam Spam/' shopping
$ hg ci -m 'SPAM'
$ cd ../local
I’ll get this remote changeset when pulling
$ hg pull remote
pulling from $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets 9ca060c80d74
(run 'hg heads' to see heads, 'hg merge' to merge)
I now have a new head. Note that this remote head is immutable.
$ hg log -G
o 9ca060c80d74 (public): SPAM
|
| @ 6445b365ad1c (draft): adding fruit
| |
| o 63ae8c44f4b6 (draft): adding condiment
|/
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Instead of merging my head with the new one. I’m going to rebase my work
$ hg diff
$ hg rebase --dest 9ca060c80d74 --source 63ae8c44f4b6
rebasing 1:63ae8c44f4b6 "adding condiment"
merging shopping
rebasing 3:6445b365ad1c "adding fruit"
merging shopping
My local work is now rebased on the remote one.
$ hg log -G
@ d300c8f961ce (draft): adding fruit
|
o 723e5a43d6d9 (draft): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Removing changesets¶
I add new items to my list.
$ cat >> shopping << EOF
> car
> bus
> plane
> boat
> EOF
$ hg ci -m 'transport'
$ hg log -G
@ 7f938a07ecb2 (draft): transport
|
o d300c8f961ce (draft): adding fruit
|
o 723e5a43d6d9 (draft): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
I have a new commit but I realize that don’t want it. (Transport shopping list does not fit well in my standard shopping list)
$ hg prune . # "." is for working directory parent
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
working directory is now at d300c8f961ce
1 changesets pruned
The silly changeset is gone.
$ hg log -G
@ d300c8f961ce (draft): adding fruit
|
o 723e5a43d6d9 (draft): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Reordering changesets¶
We create two changesets.
$ cat >> shopping << EOF
> Shampoo
> Toothbrush
> ... More bathroom stuff to come
> Towel
> Soap
> EOF
$ hg ci -m 'bathroom stuff'
$ sed -i'' -e 's/Spam/Spam Spam Spam/g' shopping
$ hg ci -m 'SPAM SPAM'
$ hg log -G
@ 1c877d31b53f (draft): SPAM SPAM
|
o d1928babc208 (draft): bathroom stuff
|
o d300c8f961ce (draft): adding fruit
|
o 723e5a43d6d9 (draft): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Note
We can’t amend changeset 7e82d3f3c2cb or 9ca060c80d74 as they are immutable.
I now want to push to remote all my changes except the bathroom one, which I’m not totally happy with yet. To be able to push “SPAM SPAM” I need a version of “SPAM SPAM” which is not a child of “bathroom stuff”.
You can use the ‘grab’ command for that.
Note
grab is an alias for hg rebase –dest . –rev <target>; hg up <result>
$ hg up 'p1(d1928babc208)' # going on "bathroom stuff" parent
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg pick 1c877d31b53f # moving "SPAM SPAM" to the working directory parent
picking 9:1c877d31b53f "SPAM SPAM"
merging shopping
$ hg log -G
@ 501b33037995 (draft): SPAM SPAM
|
| o d1928babc208 (draft): bathroom stuff
|/
o d300c8f961ce (draft): adding fruit
|
o 723e5a43d6d9 (draft): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
We have a new version of “SPAM SPAM” without the bathroom stuff
$ grep Spam shopping # enough spam
Spam Spam Spam Spam Spam Spam Spam Spam Spam
$ grep Toothbrush shopping # no Toothbrush
[1]
$ hg export .
# HG changeset patch
# User test
# Date 0 0
# Thu Jan 01 00:00:00 1970 +0000
# Node ID 501b330379955b6bf194dc99504a477b1f2d3f89
# Parent d300c8f961ceefede93601dbe478c701e2ff5995
SPAM SPAM
diff --git a/shopping b/shopping
--- a/shopping
+++ b/shopping
@@ -1,4 +1,4 @@
-Spam Spam Spam
+Spam Spam Spam Spam Spam Spam Spam Spam Spam
Whizzo butter
Albatross
Rat (rather a lot)
To make sure I do not push unfinished changeset by mistake I move the “bathroom stuff” changeset to the secret phase.
$ hg phase --force --secret d1928babc208
we can now push our change:
$ hg push remote
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 1 files
5 new obsolescence markers
for simplicity’s sake we get the bathroom change in line again
$ hg pick d1928babc208
picking 8:d1928babc208 "bathroom stuff"
merging shopping
$ hg phase --draft .
$ hg log -G
@ 39b19dc3d1e4 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Splitting change¶
This part is not written yet, but you can use either the histedit extension or the uncommit command to split a change.
$ hg help uncommit
hg uncommit [OPTION]... [FILE]...
move changes from parent revision to working directory
Changes to selected files in the checked out revision appear again as
uncommitted changed in the working directory. A new revision without the
selected changes is created, becomes the checked out revision, and obsoletes
the previous one.
The --include option specifies patterns to uncommit. The --exclude option
specifies patterns to keep in the commit.
The --rev argument let you change the commit file to a content of another
revision. It still does not change the content of your file in the working
directory.
Return 0 if changed files are uncommitted.
options ([+] can be repeated):
-a --all uncommit all changes when no arguments given
-r --rev REV revert commit content to REV instead
--revert discard working directory changes after uncommit
-n --note TEXT store a note on uncommit
-I --include PATTERN [+] include names matching the given patterns
-X --exclude PATTERN [+] exclude names matching the given patterns
-m --message TEXT use text as commit message
-l --logfile FILE read commit message from file
-d --date DATE record the specified date as commit date
-u --user USER record the specified user as committer
-D --current-date record the current date as commit date
-U --current-user record the current user as committer
(some details hidden, use --verbose to show complete help)
The edit command of histedit can be used to split changeset:
Collapsing change¶
The tutorial part is not written yet but can use hg fold:
$ hg help fold
hg fold [OPTION]... [-r] REV...
aliases: squash
fold multiple revisions into a single one
With --from, folds all the revisions linearly between the given revisions and
the parent of the working directory.
With --exact, folds only the specified revisions while ignoring the parent of
the working directory. In this case, the given revisions must form a linear
unbroken chain.
options ([+] can be repeated):
-r --rev REV [+] revision to fold
--exact only fold specified revisions
--from fold revisions linearly to working copy parent
-n --note TEXT store a note on fold
-m --message TEXT use text as commit message
-l --logfile FILE read commit message from file
-d --date DATE record the specified date as commit date
-u --user USER record the specified user as committer
-D --current-date record the current date as commit date
-U --current-user record the current user as committer
(some details hidden, use --verbose to show complete help)
Collaboration¶
Rebasing unstable change after pull¶
Remotely someone add a new changeset on top of the mutable “bathroom” on.
$ hg up 39b19dc3d1e4 -q
$ cat >> shopping << EOF
> Giraffe
> Rhino
> Lion
> Bear
> EOF
$ hg ci -m 'animals'
But at the same time, locally, this same “bathroom changeset” was updated.
$ cd ../local
$ hg up 39b19dc3d1e4 -q
$ sed -i'' -e 's/... More bathroom stuff to come/Bath Robe/' shopping
$ hg commit --amend
$ hg log -G
@ 5486682f4225 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
When we pull from remote again we get an unstable state!
$ hg pull remote
pulling from $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
1 new orphan changesets
new changesets 0609f95eccab (1 drafts)
(run 'hg update' to get a working copy)
The new changeset “animal” is based on an old changeset of “bathroom”. You can see both version showing up in the log.
$ hg log -G
* 0609f95eccab (draft): animals
|
| @ 5486682f4225 (draft): bathroom stuff
| |
x | 39b19dc3d1e4 (draft): bathroom stuff
|/
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
The older version 39b19dc3d1e4 never ceased to exist in the local repo. It was just hidden and excluded from pull and push.
Note
In hgview there is a nice dotted relation highlighting 5486682f4225 as a new version of 39b19dc3d1e4. This is not yet ported to hg log -G.
There is now an unstable changeset in this history. Mercurial will refuse to share it with the outside:
$ hg push other
pushing to $TESTTMP/other (glob)
searching for changes
abort: push includes orphan changeset: 0609f95eccab!
(use 'hg evolve' to get a stable history or --force to ignore warnings)
[255]
To resolve this unstable state, you need to rebase 0609f95eccab onto 5486682f4225. The hg evolve command will do this for you.
It has a –dry-run option to only suggest the next move.
$ hg evolve --dry-run
move:[13] animals
atop:[12] bathroom stuff
hg rebase -r 0609f95eccab -d 5486682f4225
Let’s do it
$ hg evolve
move:[13] animals
atop:[12] bathroom stuff
merging shopping
The old version of bathroom is hidden again.
$ hg log -G
o 3266db1117c9 (draft): animals
|
@ 5486682f4225 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
And let’s update to the newly evolved changeset.
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
We can push this evolution to remote.
$ hg push remote
pushing to $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files (+1 heads)
2 new obsolescence markers
obsoleted 2 changesets
Remote get a warning that current working directory is based on an obsolete changeset.
$ cd ../remote
$ hg pull local # we up again to trigger the warning. it was displayed during the push
pulling from $TESTTMP/local (glob)
searching for changes
no changes found
Now let’s see where we are, and update to the successor.
$ hg parents
0609f95eccab (draft): animals
working directory parent is obsolete! (0609f95eccab)
(use 'hg evolve' to update to its successor: 3266db1117c9)
$ hg evolve
update:[8] animals
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
working directory is now at 3266db1117c9
Relocating unstable change after prune¶
The remote guy keeps working.
$ sed -i'' -e 's/Spam/Spam Spam Spam Spam/g' shopping
$ hg commit -m "SPAM SPAM SPAM"
I’m pulling its work locally.
$ cd ../local
$ hg pull remote
pulling from $TESTTMP/remote (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets fff8c3d068b6 (1 drafts)
(run 'hg update' to get a working copy)
$ hg log -G
o fff8c3d068b6 (draft): SPAM SPAM SPAM
|
@ 3266db1117c9 (draft): animals
|
o 5486682f4225 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
In the mean time I noticed you can’t buy animals in a super market and I prune the animal changeset:
$ hg prune 3266db1117c9
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
working directory is now at 5486682f4225
1 changesets pruned
1 new orphan changesets
The animals changeset is still displayed because the “SPAM SPAM SPAM” changeset is neither dead or obsolete. My repository is in an unstable state again.
$ hg log -G
* fff8c3d068b6 (draft): SPAM SPAM SPAM
|
x 3266db1117c9 (draft): animals
|
@ 5486682f4225 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
$ hg log -r "orphan()"
fff8c3d068b6 (draft): SPAM SPAM SPAM
The –update flag of hg evolve automatically updates to the tipmost evolved changeset.
$ hg evolve --update
move:[15] SPAM SPAM SPAM
atop:[12] bathroom stuff
merging shopping
working directory is now at c33e56ec23a8
$ hg log -G
@ c33e56ec23a8 (draft): SPAM SPAM SPAM
|
o 5486682f4225 (draft): bathroom stuff
|
o 501b33037995 (public): SPAM SPAM
|
o d300c8f961ce (public): adding fruit
|
o 723e5a43d6d9 (public): adding condiment
|
o 9ca060c80d74 (public): SPAM
|
o 7e82d3f3c2cb (public): Monthy Python Shopping list
Handling Divergent amend¶
We can detect that multiple diverging amendments have been made. The evolve command can solve this situation. But all corner case are not handled now.
This section needs to be written.