Re: [PATCHv2] lib/bb: Add BB_SIGNATURE_LOCAL_DIRS_EXCLUDE to speed-up taskhash on directories

[Peter Kjellerstedt <peter.kjellerstedt@axis.com>]

> -----Original Message-----
> From: bitbake-devel-bounces@lists.openembedded.org <bitbake-devel-
> bounces@lists.openembedded.org> On Behalf Of Aníbal Limón
> Sent: den 15 november 2019 15:47
> To: bitbake-devel@lists.openembedded.org
> Subject: [bitbake-devel] [PATCHv2] lib/bb: Add
> BB_SIGNATURE_LOCAL_DIRS_EXCLUDE to speed-up taskhash on directories
> 
> The new BB_SIGNATURE_LOCAL_DIRS_EXCLUDE allows you to specify a list
> of directories to exclude when making taskhash, our specific case
> is using SRC_URI that points local VCS directory.
> 
> Use bb.fetch.module to set default to: "CVS .bzr .git .hg .osc .p4 .repo
> .svn"
> 
> Signed-off-by: Aníbal Limón <anibal.limon@linaro.org>
> ---
>  lib/bb/checksum.py        | 5 +++--
>  lib/bb/fetch2/__init__.py | 4 ++--
>  lib/bb/siggen.py          | 5 +++--
>  3 files changed, 8 insertions(+), 6 deletions(-)

[cut]

> --- a/lib/bb/siggen.py
> +++ b/lib/bb/siggen.py
> @@ -123,6 +123,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
> 
>          self.unihash_cache = bb.cache.SimpleCache("1")
>          self.unitaskhashes = self.unihash_cache.init_cache(data, "bb_unihashes.dat", {})
> +        self.localdirsexclude = (data.getVar("BB_SIGNATURE_LOCAL_DIRS_EXCLUDE") or "CVS .bzr .git .hg .osc .p4 .repo .svn").split()

I don't like this construct, because if I do:

BB_SIGNATURE_LOCAL_DIRS_EXCLUDE_append = " some_dir"

it means that all of a sudden the SCM directories listed above will no 
longer be excluded since BB_SIGNATURE_LOCAL_DIRS_EXCLUDE will now be 
defined, but only contain " some_dir". Isn't it better to add:

BB_SIGNATURE_LOCAL_DIRS_EXCLUDE ??= "CVS .bzr .git .hg .osc .p4 .repo .svn"

somewhere in OE-Core (and it can then also have a suitable 
BB_SIGNATURE_LOCAL_DIRS_EXCLUDE[doc], though it seems BB_-variables 
are only documented in meta/conf/documentation.conf)?

Alternatively, to keep the list above within bitbake, make it two 
variables, one for the list of directories above that is not really 
intended to be modified, and one for additional directories (which 
should still be documented in meta/conf/documentation.conf).

//Peter