Re: [PATCH 2/3] fetch2: Gracefully handle corrupt download-cache tarballs

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Mon, 2019-03-18 at 14:58 +0100, Stefan Klug wrote:
> If the fullmirror tarball is corrupt for whatever reason
> (IMHO there are no checksums on the download cache)
> a series of nasty events was triggered:
> - tar left a partially extracted bare git repo there
> - on the next yocto build, the corrupt bare repo is
>   found and bitbake starts to update that bare repo using git
> - git fails to detect it as bare repo. Therefore
>   all following git commands ripple up the directory tree,
>   in our case modifying a top level git repo.
> 
> Signed-off-by: Stefan Klug <stefan.klug@baslerweb.com>
> ---
>  lib/bb/fetch2/git.py | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/bb/fetch2/git.py b/lib/bb/fetch2/git.py
> index 1a8ebe3d..d5f9bbcd 100644
> --- a/lib/bb/fetch2/git.py
> +++ b/lib/bb/fetch2/git.py
> @@ -334,8 +334,11 @@ class Git(FetchMethod):
>              ud.localpath = ud.fullshallow
>              return
>          elif os.path.exists(ud.fullmirror) and not os.path.exists(ud.clonedir):
> -            bb.utils.mkdirhier(ud.clonedir)
> -            runfetchcmd("tar -xzf %s" % ud.fullmirror, d, workdir=ud.clonedir)
> +            try:
> +                bb.utils.mkdirhier(ud.clonedir)
> +                runfetchcmd("tar -xzf %s" % ud.fullmirror, d, workdir=ud.clonedir, cleanup=[ud.clonedir])
> +            except:
> +                logger.info("Extracting tarball of git repository failed, falling back to clone.")

General "except:" clauses are a world of pain. Can we be more specific
here?

For an example of what I mean, put a syntax error in the command...

Cheers,

Richard