Differences between revisions 1 and 30 (spanning 29 versions)
Revision 1 as of 2006-06-03 15:50:07
Size: 1878
Editor: ?Andreas Fester
Comment:
Revision 30 as of 2016-08-18 23:42:02
Size: 5514
Editor: GuillemJover
Comment: Improve methods and update with current information
Deletions are marked like this. Additions are marked like this.
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Sometimes, it is necessary for a package to get a new name. Although it should rather seldom be the case, there are some situations when this makes sense, for example when the name of the upstream application changes. Of course an ''apt-get dist-upgrade'' should seamless upgrade the package, best by completely removing the old package and installing the new one as a replacement. Sometimes, it is necessary for a package to get a new name. Although this should rather seldom be the case, there are some situations when it makes sense, for example when the name of the upstream application changes. Of course an ''apt-get dist-upgrade'' should still seamlessly upgrade the package, best by completely removing the old package and installing the new one as a replacement.
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== Clean slate method ==
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== Method A == One method is to switch to the new name without using a transitional package. It can imply renaming the binary package within the existing source (and possibly renaming the source package) or creating a new source package (which would require a request removal of the old source package). And let the new package '''Provides''', '''Replaces''' and '''Conflicts''' the old package, ideally by using versioned Provides to fulfill versioned dependencies when targeting >= Debian Stretch.

This should be used for example for any non-leaf packages that are only ever installed by other packages depending on it. Because in that case the only thing needed will be for the reverse-dependencies to start depending on the new package.

But this method has disadvantages:

 * Cannot be used for packages that are used in build dependencies, as several build tools (like DebianPkg:sbuild) do not support virtual packages in those dependencies by design, to guarantee deterministic builds.
 * Most package managers (including APT, as of 2011-02-21) do not know to replace the old with the new one and will only use the new package if it is installed for some other reason.

== Transition package method ==

Basically, the solution is to define a binary dummy package with the same name as the old package in the control file of the new package. The new source package takes over the binary dummy package, and the old source package, which is then binaryless, will be cleaned up by {{{rene}}}, an archive cleanup tool.

Assume that the last upstream version of the old package "oldname" was 1.5 and the package was renamed to "newname" for version 2.0.

Then, the dummy package is defined like this in debian/control:
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 Package: oldpkg
 Depends: newpkg
 Version: 1.0
 Description: transitional dummy package
}}}
{{{
 Package: newpkg
 Replaces: oldpkg (<< 1.0)
 Package: oldname
 Depends: newname, ${misc:Depends}
 Architecture: all
 Priority: extra
 Section: oldlibs
 Description: transitional package
  This is a transitional package. It can safely be removed.
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== Method B == This entry defines the binary dummy package. It will get version 2.0-1 and automatically be pulled in by an {{{apt-get dist-upgrade}}} if an earlier version of oldname was already installed. Be sure to use the term "transitional package" in the long description as various tools (lintian, deborphan, etc.) look for exactly those two words.
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There is an even more elegant way which installs less files and effectively provides a real replacement mechanism. The package only installs the mandatory files in /usr/share/doc/oldname
and possibly some compatibility symlinks, see below.
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The dummy package is defined like this in {{{debian/control}}}: Since it depends on newname, it also installs the new package.

Note that the package does not contain any architecture specific files anymore and therefore the Architecture is set to '''all''', even if it was '''any''' before.

If you set the section of the dummy package to oldlibs, tools like deborphan
will suggest removal of the package once there aren't any more reverse-dependencies installed.

The new package is defined like this:
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 Package: oldpkg
 Depends: newpkg
 Package: newname
 Replaces: oldname (<< 2.0-1~)
 Breaks: oldname (<< 2.0-1~)
 …
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The dummy package only installs a link (and nothing else!) like {{{/usr/share/doc/oldpkg -> /usr/share/doc/newpkg}}}, for example with the dh_link debhelper script. You can also add a versioned {{{Provides:}}} entry if it is appropriate (for example when all interfaces are provided), which will help to satisfy any versioned reverse dependencies, and will allow users to remove the transitional package.
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The new package is defined like this in {{{debian/control}}}: Please make sure that you use the proper version to break against. You must make sure that you break against all versions which still have the files in the old package. Especially if you split it between two Debian revisions, you must add a Debian revision and not only conflict against older upstream versions. (Or you will stumble across bugs like [[DebianBug:397993|#397993]]).
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{{{
 Package: newpkg
 Replaces: oldpkg
 Provides: oldpkg
}}}
=== Compatibility symlinks ===
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The new package installs all its necessary files and the same link as the dummy package, {{{/usr/share/doc/oldpkg -> /usr/share/doc/newpkg}}} If your new package also changes some filename-based interfaces to users or other packages, for example the package name changed because the program name changed, you might want to add compatibility symlinks. Those can either be placed in the old or the new package. If the symlink is there to stay, place it in the new package (so users can remove the transitional package and still have it). If the symlink is supposed to go away, placing it in the old package has the advantage that users can choose to have it or not (of couse make sure to give the old package a proper description stating that it contains that compatibility) and that there is an easy way to see which other packages still need to change (things depending on the old name may need the compatibility symlink, while things depending on the new name must call it with the new name). As packages that have been in a release will need to have the transitional package in the next release, that extra information is especially useful if
the package never released so the transitional package can be removed soon or if there are chances the transition to the new name will take more than one release to have all reverse-dependencies fixed).
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Now, when an earlier version of the oldPkg is installed and the system is upgraded with {{apt-get dist-upgrade}}, the new version of the dummy package is installed which pulls in the new package newPkg. The link is then taken over by newPkg, so that no installed files remain for the old dummy package oldPkg. {{{dpkg}}} is aware of this situation and notices that oldPkg is now completely replaced. However, through a bug in dpkg, it tries to configure the old dummy package at a later time, which fails because the package was already removed. Thus, at least for etch, this approach can not be used. This page used to describe a method trying to get rid of the transitional package automatically by removing all it files. If you are interested why this does not work at all, take a look at the history of this page.
 
 . CategoryDeveloper

Why?

Sometimes, it is necessary for a package to get a new name. Although this should rather seldom be the case, there are some situations when it makes sense, for example when the name of the upstream application changes. Of course an apt-get dist-upgrade should still seamlessly upgrade the package, best by completely removing the old package and installing the new one as a replacement.

Clean slate method

One method is to switch to the new name without using a transitional package. It can imply renaming the binary package within the existing source (and possibly renaming the source package) or creating a new source package (which would require a request removal of the old source package). And let the new package Provides, Replaces and Conflicts the old package, ideally by using versioned Provides to fulfill versioned dependencies when targeting >= Debian Stretch.

This should be used for example for any non-leaf packages that are only ever installed by other packages depending on it. Because in that case the only thing needed will be for the reverse-dependencies to start depending on the new package.

But this method has disadvantages:

  • Cannot be used for packages that are used in build dependencies, as several build tools (like sbuild) do not support virtual packages in those dependencies by design, to guarantee deterministic builds.

  • Most package managers (including APT, as of 2011-02-21) do not know to replace the old with the new one and will only use the new package if it is installed for some other reason.

Transition package method

Basically, the solution is to define a binary dummy package with the same name as the old package in the control file of the new package. The new source package takes over the binary dummy package, and the old source package, which is then binaryless, will be cleaned up by rene, an archive cleanup tool.

Assume that the last upstream version of the old package "oldname" was 1.5 and the package was renamed to "newname" for version 2.0.

Then, the dummy package is defined like this in debian/control:

 Package: oldname
 Depends: newname, ${misc:Depends}
 Architecture: all
 Priority: extra
 Section: oldlibs
 Description: transitional package
  This is a transitional package. It can safely be removed.

This entry defines the binary dummy package. It will get version 2.0-1 and automatically be pulled in by an apt-get dist-upgrade if an earlier version of oldname was already installed. Be sure to use the term "transitional package" in the long description as various tools (lintian, deborphan, etc.) look for exactly those two words.

The package only installs the mandatory files in /usr/share/doc/oldname and possibly some compatibility symlinks, see below.

Since it depends on newname, it also installs the new package.

Note that the package does not contain any architecture specific files anymore and therefore the Architecture is set to all, even if it was any before.

If you set the section of the dummy package to oldlibs, tools like deborphan will suggest removal of the package once there aren't any more reverse-dependencies installed.

The new package is defined like this:

 Package: newname
 Replaces: oldname (<< 2.0-1~)
 Breaks: oldname (<< 2.0-1~)

You can also add a versioned Provides: entry if it is appropriate (for example when all interfaces are provided), which will help to satisfy any versioned reverse dependencies, and will allow users to remove the transitional package.

Please make sure that you use the proper version to break against. You must make sure that you break against all versions which still have the files in the old package. Especially if you split it between two Debian revisions, you must add a Debian revision and not only conflict against older upstream versions. (Or you will stumble across bugs like #397993).

If your new package also changes some filename-based interfaces to users or other packages, for example the package name changed because the program name changed, you might want to add compatibility symlinks. Those can either be placed in the old or the new package. If the symlink is there to stay, place it in the new package (so users can remove the transitional package and still have it). If the symlink is supposed to go away, placing it in the old package has the advantage that users can choose to have it or not (of couse make sure to give the old package a proper description stating that it contains that compatibility) and that there is an easy way to see which other packages still need to change (things depending on the old name may need the compatibility symlink, while things depending on the new name must call it with the new name). As packages that have been in a release will need to have the transitional package in the next release, that extra information is especially useful if the package never released so the transitional package can be removed soon or if there are chances the transition to the new name will take more than one release to have all reverse-dependencies fixed).

This page used to describe a method trying to get rid of the transitional package automatically by removing all it files. If you are interested why this does not work at all, take a look at the history of this page.