Re: kbuild: Fix the breakage caused by "improve version string logic"

David Rientjes
2010-06-08T09:13:24Z

On Tue, 8 Jun 2010, Boaz Harrosh wrote:

>
> The patch: 85a256d8e0116c8f5ad276730830f5d4d473344d
> Author: David Rientjes <rientjes@google.com>
> Title: kbuild: improve version string logic
>
> Broke none Linus trees that supply their own version string and
> tag system via a presence of a localversion* file at the Kernel's
> root subdirectory.
>
> After This patch. The "+" (plus) is not added if a localversion*
> file is present or a CONFIG_LOCALVERSION is configured.
>

The only reason the `+' is being appended to your version string is
because your scm is reporting that there have been commits to the tree
since the last release; for git, that means anything that isn't at a
tagged commit.

If you were to create a tarball of your tree, for instance, and distribute
it to someone else, there would be no appended `+' because there is no
revision history. The `+' being appended simply implies that you're
beyond the base kernel version in an scm. The motivation is to be more
descriptive about what kernel is being run: the most common case where
this comes into play is when someone is running a kernel off of Linus'
tree and a bug report incorrectly shows that it is a vanilla 2.6.35-rc2
kernel, for instance.

When we discussed adding this indicator of revision history, we explicitly
noted that the `+' is a modification of the base kernel version, not the
entire string.

As mentioned previously, you can easily suppress that from being added by
using "make LOCALVERSION=-foo" to create a 2.6.35-rc2-foo kernel when you
do not have CONFIG_LOCALVERSION_AUTO enabled. You already found that you
cannot pass an empty LOCALVERSION string, so it must be something to
identify itself as unique from vanilla 2.6.35-rc2.

The usecase that you've cited before is your colleagues pulling your git
tree and then getting this `+' appended when they really don't want it.
Although localversion* files are better than (ab)using the EXTRAVERSION
variable in the Makefile, they won't suppress the `+' because your
revision history shows that you're beyond a released (tagged) kernel. The
solution is to use git-tag to indicate your particular version of Linux
that differentiates it from vanilla 2.6.35-rc2 and pass along your version
information with either localversion* files or CONFIG_LOCALVERSION if you
package your .config as well.