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'''Bazaar''' is another ["DistributedSCM"] (see http://bazaar-vcs.org/). '''Bazaar''' is another [[DistributedSCM]] (see http://bazaar-vcs.org/).
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A Bazaar "branch" roughly corresponds to a Mercurial [:Repository:repository]. Bazaar's "branch" command corresponds to "[:Clone:clone]" in Mercurial. A Bazaar "branch" roughly corresponds to a Mercurial [[Repository|repository]]. Bazaar's "branch" command corresponds to "clone" in Mercurial.
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[[TableOfContents]] <<TableOfContents>>
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In Bazaar, the [http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html#push push command] has an {{{--overwrite}}} option '''which modifies the history''' of the target branch. Example: In Bazaar, the [[http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html#push|push command]] has an {{{--overwrite}}} option '''which modifies the history''' of the target branch (provided the target branch was not explicitly created using the {{{--append-revisions-only}}} option, see addendum below). Example:
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Assume we have a Bazaar branch in directory {{{bzr1}}} and branched that to {{{bzr1-1}}} (using {{{bzr branch bzr1 bzr1-1}}}). Then we commit some changes in both branches, thus making the branches diverge. Assume we have a Bazaar branch in directory {{{bzr1}}} (created with "{{{bzr init}}}") and branched that to {{{bzr1-1}}} (using {{{bzr branch bzr1 bzr1-1}}}). Then we commit some changes in both branches, thus making the branches diverge.
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by changeing the history of {{{bzr1}}}. '''Some already committed changes to branch {{{bzr1}}} are deleted''' (the diverging changes). ~-Quote from Bazaar manual: ''"If branches have diverged, you can use 'bzr push --overwrite' to replace the other branch completely, discarding its unmerged changes."''-~ by changing the history of {{{bzr1}}}. '''Some already committed changes to branch {{{bzr1}}} are deleted''' (the diverging changes). ~-Quote from Bazaar manual: ''"If branches have diverged, you can use 'bzr push --overwrite' to replace the other branch completely, discarding its unmerged changes."''-~

'''Addendum''': If branch {{{bzr1}}} is created using
{{{
bzr init --append-revisions-only
}}}

(see [[http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html#init|bzr init]]), then {{{push --overwrite}}} will be denied if the branches have diverged:

{{{
> bzr push ..\bzr1 --overwrite
bzr: ERROR: Operation denied because it would change the main history, which is not permitted by the append_revisions_only setting on branch "C:/tmp/bzr1/".
}}}

So this ensures that pushes cannot change existing history (however, this is not the default behaviour).
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In Mercurial, it is not possible to delete already committed changesets when doing a [:Push:push]. In Mercurial, it is not possible to delete already committed changesets when doing a [[Push|push]].
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in Mercurial will simply add a new [:Head:head] to the target repository. History is preserved. simply adds a new [[Head|head]] to the target repository. History is preserved. (Sidenote: This is inherent in Mercurial, as the underlying [[Revlog|revlog]] format used for all versioned information in Mercurial is ''append only'' by design).
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 * ["BzrVsHg"]
 * [http://www.selenic.com/pipermail/mercurial-devel/2008-January/004361.html bzr wins a performance test], by Bryan O'Sullivan, Fri Jan 18 15:33:47 CST 2008		  * [[BzrVsHg]]
 * [[http://www.selenic.com/pipermail/mercurial-devel/2008-January/004361.html|bzr wins a performance test]], by Bryan O'Sullivan, Fri Jan 18 15:33:47 CST 2008
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 * ["SpiderGoat"]  * [[SpiderGoat]]
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 * [http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html Bazaar User Reference] (manual)
 * [http://www.selenic.com/mercurial/hg.1.html Mercurial man page]		  * [[http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html|Bazaar User Reference]] (manual)
 * [[http://www.selenic.com/mercurial/hg.1.html|Mercurial man page]]

Bazaar is another DistributedSCM (see http://bazaar-vcs.org/).

A Bazaar "branch" roughly corresponds to a Mercurial repository. Bazaar's "branch" command corresponds to "clone" in Mercurial.

Contents

  1. Comparing Use Cases
    1. Push
  2. General Comparison
  3. See also
  4. References

Comparing Use Cases

Push

Bazaar

In Bazaar, the push command has an --overwrite option which modifies the history of the target branch (provided the target branch was not explicitly created using the --append-revisions-only option, see addendum below). Example:

Assume we have a Bazaar branch in directory bzr1 (created with "bzr init") and branched that to bzr1-1 (using bzr branch bzr1 bzr1-1). Then we commit some changes in both branches, thus making the branches diverge.

Then in bzr1-1 doing: 

> bzr push ..\bzr1
bzr: ERROR: These branches have diverged.  Try using "merge" and then "push".

will fail because the two branches have diverged.

But specifying --overwrite will succeed: 

> bzr push ..\bzr1 --overwrite
All changes applied successfully.
Pushed up to revision 2.

by changing the history of bzr1. Some already committed changes to branch bzr1 are deleted (the diverging changes). Quote from Bazaar manual: "If branches have diverged, you can use 'bzr push --overwrite' to replace the other branch completely, discarding its unmerged changes."

Addendum: If branch bzr1 is created using 

bzr init --append-revisions-only

(see bzr init), then push --overwrite will be denied if the branches have diverged: 

> bzr push ..\bzr1 --overwrite
bzr: ERROR: Operation denied because it would change the main history, which is not permitted by the append_revisions_only setting on branch "C:/tmp/bzr1/".

So this ensures that pushes cannot change existing history (however, this is not the default behaviour).

Mercurial

In Mercurial, it is not possible to delete already committed changesets when doing a push.

Assume we have two Mercurial repositories hg1 and hg1-1 (hg1-1 cloned at some time from hg1) with diverging changes. In hg1-1 doing: 

> hg push ..\hg1
pushing to ..\hg1
searching for changes
abort: push creates new remote branches!
(did you forget to merge? use push -f to force)

will fail as with bzr push. But doing: 

> hg push --force ..\hg1
pushing to ..\hg1
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)

simply adds a new head to the target repository. History is preserved. (Sidenote: This is inherent in Mercurial, as the underlying revlog format used for all versioned information in Mercurial is append only by design).

General Comparison

See also

References

Bazaar (last edited 2012-11-06 12:47:33 by abuehl)