Diff for "ConcatenatingChangesets"

Differences between revisions 1 and 22 (spanning 21 versions)

Concatenating multiple changesets into one

(See also EditingHistory)

Problem

Suppose you want to concatenate the last k changesets of a repository

into a single, combined changeset

Solution (using hg only)

Execute the following steps:

1: hg -R oldrepo update S

This updates the working directory to revision S. Specifically, this means that the contents of the working directory are changed to that of revision S, and that S becomes the parent of the working directory.

2: hg -R oldrepo revert -r tip --all

This reverts the working directory to its contents at tip. Since the parent of the working directory is still S, this means that the combined contents of all changesets between S and S+k show up as the modifications in the working directory.

3: hg -R oldrepo commit -m "Combine changesets S+1..S+k"

Committing these modifications creates a new changeset "S+k (combined)", containing combined changesets S+1 to S+k.

4: hg clone -r tip oldrepo newrepo

This assumes you want to get rid of your individual changesets (which are a dangling branch in oldrepo) and just keep the combined changeset. newrepo will now just have the combined changeset.
$/!\$ This will strip out all other branches, not just the one dangling branch that you don't want. If you have other branches that you want to keep, specify their head revisions or branch names on the clone call:
- hg clone -r tip -r branch1 -r branch2 -r branch3 oldrepo newrepo
Or you can use the strip command provided by the Mercurial Queues Extension. Note that if you're planning to use mq, there's a much more convenient way to do the above...

Alternative Solution (using mq)

Integrate the changesets you want to concatenate in a patch queue (verify you don't have pending patches there using hg qseries).
1: hg qimport -r S:tip

Pop all the patches but the first.
2: hg qgoto qbase

"Fold" unapplied patches, i.e. concatenate changesets.
3: hg qfold $(hg qunapp)
This has the big advantage over the previous method that the commit messages will also be concatenated (separated by the * * * string). You can see the message using hg qhead and edit it using hg qrefresh -e.

Reintegrate the folded patch in the repository.
4: hg qdel -r qbase
tip is now the concatenation of former changesets S:tip. There's no extra branch left, therefore no additional cleanup to do.

CategoryTipsAndTricks

-  ⇤ ← Revision 1 as of 2008-03-23 09:49:33 → 
  Size: 2828
  Editor: abuehl
  Comment: moved from TipsAndTricks/Advanced
+   ← Revision 22 as of 2009-05-19 19:31:05 → ⇥
  Size: 4058
  Editor: localhost
  Comment: converted to 1.6 markup
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-== Concatenating multiple changesets into one changeset ==
+== Concatenating multiple changesets into one ==
 Line 3:
-Suppose you have a repository with a number of changesets which you
want to combine into a single changeset.
+''(See also [[EditingHistory]])''
-Line 6:
+Line 5:
-This can be done as follows using only the basic operations of
mercurial, namely clone, push, pull.
+=== Problem ===
Suppose you want to concatenate the last k changesets of a [[Repository|repository]]
-Line 9:
+Line 8:
-For simplicity, let us assume that the repository in question has a
single head, and you want to combine the last k revisions into a
single revision.

For concreteness, let us call the base revision R, and the ending
revision R+k.

Let us furthermore assume the repository has no local changes.

The strategy is to take advantage of mercurial's support for
repositories with more than one head. What we do is create a branch
whose root revision is R and which consists of just one changeset
(actually it can be multiple changesets, the principle is the same,
but for simplicity let us assume one).

Diagramatically, this looks like:

{{{#!dot
+ {{{#!dot
-Line 28:
+Line 10:
-  rankdir = BT;
+  rankdir = LR;
-Line 30:
+Line 12:
-  "working directory" -> R [label="1. update"];
  R -> "R+1" -> "R+2";
  "R+2" -> "R+k" [style=dashed];
  "working directory" -> "R+k" [color=red label="2. revert"];
  "working directory" [shape=ellipse];
+  S -> "S+1" -> "S+2";
  "S+2" -> "S+k" [style=dashed];
  label="oldrepo"
-Line 37:
+Line 17:
-{{{#!dot
+into a single, combined changeset

 {{{#!dot
-Line 39:
+Line 21:
-  rankdir = BT;
+  rankdir = LR;
-Line 41:
+Line 23:
-  "working directory" -> "R+k (concatenated)" [color=red label="3. commit"];
  "working directory" -> R [style=invis];
  R -> "R+k (concatenated)";
  R -> "R+1" -> "R+2";
  "R+2" -> "R+k" [style=dashed];
  "working directory" [shape=ellipse];
+  S -> "S+k (combined)"
  label="newrepo"
-Line 49:
+Line 27:
-{{{#!dot
+=== Solution (using hg only) ===
Execute the following steps:

'''~+{{{1: hg -R oldrepo update S}}}+~'''

 This [[Update|updates]] the [[WorkingDirectory|working directory]] to revision S.
 Specifically, this means that the contents of the working directory are
 changed to that of revision S, and that S becomes the [[Parent|parent]]
 of the working directory.


'''~+{{{2: hg -R oldrepo revert -r tip --all}}}+~'''

 {{{#!dot
-Line 51:
+Line 42:
-  rankdir = BT;
+  rankdir = LR;
-Line 53:
+Line 44:
-  "working directory" -> R [style=invis];
  "working directory" -> "R+k (concatenated)" [color=red label="4. clone -r tip"]
  R -> "R+k (concatenated)"
  "working directory" [shape=ellipse label="cloned working directory"]
+  "working directory" -> S [label="1. update"];
  S -> "S+1" -> "S+2";
  "S+2" -> "S+k" [style=dashed];
  "working directory" -> "S+k" [color=red label="2. revert"];
  "working directory" [shape=ellipse];
  label="oldrepo"
-Line 59:
+Line 52:
+ This [[Revert|reverts]] the working directory to its contents at [[Tip|tip]].
 Since the parent of the working directory is still S, this means that
 the combined contents of all changesets between S and S+k show up as
 the modifications in the working directory.
-Line 60:
+Line 57:
-The procedure is as follows.
-Line 62:
+Line 58:
-. hg update R
    This updates the working directory to revision R. Specifically, this
    means that the contents of the working directory are changed to that
    of revision R, and that R becomes the parent of the working directory.
+'''~+{{{3: hg -R oldrepo commit -m "Combine changesets S+1..S+k"}}}+~'''
-Line 67:
+Line 60:
-. hg revert -r tip --all
    This reverts the working directory to its contents at tip.
    Since the parent of the working directory is still R, this means that
    the combined contents of all changesets between R and R+k show up as
    the modifications in the working directory.
+ {{{#!dot
digraph {
  rankdir = LR;
  node [shape=box];
  "working directory" -> "S+k (combined)" [color=red label="3. commit"];
  "working directory" -> S [style=invis];
  S -> "S+k (combined)";
  S -> "S+1" -> "S+2";
  "S+2" -> "S+k" [style=dashed];
  "working directory" [shape=ellipse];
  label="oldrepo"
}}}
 Line 73:
-. hg ci -m "Combined changesets between R and R+k"
    At this point, committing these modifications will create a changeset
    containing all combined changesets between revisions R and R+k.
+ [[Commit|Committing]] these modifications creates a
 new changeset "S+k (combined)", containing combined changesets S+1 to S+k.
-Line 77:
+Line 76:
-. hg clone -r tip oldrepo newrepo
    This assumes you want to get rid of your individual changesets
    (which are a dangling branch in oldrepo) and just keep the combined
    changeset. newrepo will now just have the combined changeset.
+'''~+{{{4: hg clone -r tip oldrepo newrepo}}}+~'''

 {{{#!dot
digraph {
  rankdir = LR;
  node [shape=box];
  "working directory" -> S [style=invis];
  "working directory" -> "S+k (combined)" [color=red label="4. clone -r tip"]
  S -> "S+k (combined)"
  "working directory" [shape=ellipse label="cloned working directory"]
  label="newrepo"
}}}

 <<BR>>This assumes you want to get rid of your individual changesets (which are a dangling [[Branch|branch]] in oldrepo) and just keep the combined changeset. newrepo will now just have the combined changeset.

 /!\ This will strip out '''all''' other branches, not just the one dangling branch ''that you don't want.'' If you have other branches that you want to keep, specify their [[Head|head]] revisions or [[NamedBranches|branch names]] on the [[Clone|clone]] call:
 
  {{{hg clone -r tip -r branch1 -r branch2 -r branch3 oldrepo newrepo}}}

 Or you can use the {{{strip}}} command provided by the [[MqExtension|Mercurial Queues Extension]].
 Note that if you're planning to use mq, there's a much more convenient way to do the above...

=== Alternative Solution (using mq) ===

Integrate the changesets you want to concatenate in a patch queue (verify you don't have pending patches there using {{{hg qseries}}}). <<BR>>
'''~+{{{1: hg qimport -r S:tip}}}+~'''

Pop all the patches but the first. <<BR>>
'''~+{{{2: hg qgoto qbase}}}+~''' 

"Fold" unapplied patches, i.e. concatenate changesets. <<BR>>
'''~+{{{3: hg qfold $(hg qunapp)}}}+~''' <<BR>>
This has the big advantage over the previous method that the commit messages will also be concatenated (separated by the {{{* * *}}} string). You can see the message using {{{hg qhead}}} and edit it using {{{hg qrefresh -e}}}.

Reintegrate the folded patch in the repository. <<BR>>
'''~+{{{4: hg qdel -r qbase}}}+~''' <<BR>>
{{{tip}}} is now the concatenation of former changesets {{{S:tip}}}. There's no extra branch left, therefore no additional cleanup to do.

----
CategoryTipsAndTricks