[Buildroot] [PATCH RFC] core/pkg-download: ignore hashes from mirror for VCS downloads

[Yann E. MORIN]

When a download via a VCS method fails, Buildroot attempts the download
from the backup mirror (if any is set). Such a download is done with the
wget helper.

Given a package that has a .hash file for relase tarballs, which also
allows the user to use a random revision from a VCS, the normal download
wrapper will not check for hashes, on the assumption that maybe they are
not reproducible [*].

However, when the download fails (for any reason: network error,
upstream removed the revision, old machine with incomplete set of CA
certificates...), the backup download now proceeds over with http (or
https) with the wget wrapper. The wget wrapper *always* checks for
hashes, and when a .hash file is present but no hash is found for the
download, this is considered an error.

However, when we download from the backup mirror for a main download
that should have been done with git, we in this situation have no hash
for the download. Thus, we should not fail on a missing hash for that
download.

Add a test for the site-method in the backup mirror download; if it was
either one of the VCS method, pass a one-off BR_NO_CHECK_HASH_FOR
variable set to contain the tarball to download.

Fixes issues like those reported by the Travis build bots:
    https://travis-ci.org/buildroot/buildroot-defconfig-testing/jobs/123624879

Reported-by: Peter Korsgaard <peter at korsgaard.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>

---
Note: untested.
---
 package/pkg-download.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/pkg-download.mk b/package/pkg-download.mk
index 1332e66..d68b7bc 100644
--- a/package/pkg-download.mk
+++ b/package/pkg-download.mk
@@ -235,6 +235,7 @@ define DOWNLOAD_INNER
 		esac ; \
 	fi ; \
 	if test -n "$(call qstrip,$(BR2_BACKUP_SITE))" ; then \
+		$(if $(filter bzr cvs git hg svn,$($(PKG)_SITE_METHOD)),BR_NO_CHECK_HASH_FOR=$(2)) \
 		$(call $(3)_WGET,$(BR2_BACKUP_SITE)/$(2),$(2)) && exit ; \
 	fi ; \
 	exit 1
-- 
1.9.1