sstate: Change overlapping files warning to a fatal error

When files overlap in the sysroot, something bad usually happened. We've had
two independent cases recently where a couple of months after one of these
warnings was shown, builds failed due to corruption.

This change moves the warning to become a fatal error. The complaint I've had
about this is that we need to tell the user what happened and more importantly
how to recover from it. If we could recover from it, great but the trouble is
we simply don't know what happened.

As a compromise, we can document several of the possible scenarios in the error
message. We don't normally go to this level of detail however in this case, I'm
lacking other viable alternatives.

I do believe it is important to stop as corruption occurs rather than letting the
build contunue into territory that is not deterministic amongst other things.

The complex message is followed by a simpler one in case the long message is too
much for the user.

(From OE-Core rev: 179ac7de03977b6e440409eddb2166819e07286a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index 4057c8c833..72ac882dbb 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -187,7 +187,8 @@ def sstate_install(ss, d):
                 if search_output != "":
                     match.append("Matched in %s" % search_output.rstrip())
     if match:
-        bb.warn("The recipe %s is trying to install files into a shared area when those files already exist. Those files and their manifest location are:\n   %s\nPlease verify which package should provide the above files." % (d.getVar('PN', True), "\n   ".join(match)))
+        bb.fatal("The recipe %s is trying to install files into a shared area when those files already exist. Those files and their manifest location are:\n   %s\nPlease verify which recipe should provide the above files.\nThe build has stopped as continuing in this scenario WILL break things, if not now, possibly in the future (we've seen builds fail several months later). If the system knew how to recover from this automatically it would however there are several different scenarios which can result in this and we don't know which one this is. It may be you have switched providers of something like virtual/kernel (e.g. from linux-yocto to linux-yocto-dev), in that case you need to execute the clean task for both recipes and it will resolve this error. It may be you changed DISTRO_FEATURES from systemd to udev or vice versa. Cleaning those recipes should again resolve this error however switching DISTRO_FEATURES on an existing build directory is not supported, you should really clean out tmp and rebuild (reusing sstate should be safe). It could be the overlapping files detected are harmless in which case adding them to SSTATE_DUPWHITELIST may be the correct solution. It could also be your build is including two different conflicting versions of things (e.g. bluez 4 and bluez 5 and the correct solution for that would be to resolve the conflict. If in doubt, please ask on the mailing list, sharing the error and filelist above." % (d.getVar('PN', True), "\n   ".join(match)))
+        bb.fatal("If the above message is too much, the simpler version is you're advised to wipe out tmp and rebuild (reusing sstate is fine). That will likely fix things in most (but not all) cases.")
 
     # Write out the manifest
     f = open(manifest, "w")