regression: “dns: overflow packing opt” after EDNS0 commit

[stapelberg]

Starting at commit a98e771, my router7 tests start failing:

~/go/src/github.com/miekg/dns master % git reset --hard 22cda6dc4f8b43ab129d7e79c24975180a0aace6
HEAD is now at 22cda6dc Speed up NextLabel and PrevLabel (#1039)

~router7 % go test -count=1 github.com/rtr7/router7/integration/dns 
ok  	github.com/rtr7/router7/integration/dns	0.013s

~/go/src/github.com/miekg/dns master % git reset --hard a98e771ba54f32f7273c037cb8a6e7a7aef6a654
HEAD is now at a98e771b Export EDNS0 interface (#1041)

~router7 % go test -count=1 github.com/rtr7/router7/integration/dns
2019/12/06 21:52:56 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt
2019/12/06 21:52:57 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt
2019/12/06 21:52:58 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt
--- FAIL: TestDNS (3.01s)
    dns_test.go:38: exit status 9
FAIL
FAIL	github.com/rtr7/router7/integration/dns	3.011s
FAIL

Not sure if the mistake is easy to spot, so let me know if you need more details.

Thanks!

[miekg]

[ Quoting <notifications@github.com> in "[miekg/dns] regression: “dns: overf..." ]

Starting at commit a98e771, my router7 tests start failing: ``` ~/go/src/github.com/miekg/dns master % git reset --hard 22cda6d ~router7 % go test -count=1 github.com/rtr7/router7/integration/dns ok github.com/rtr7/router7/integration/dns 0.013s ~/go/src/github.com/miekg/dns master % git reset --hard a98e771 HEAD is now at a98e771 Export EDNS0 interface (#1041) ~router7 % go test -count=1 github.com/rtr7/router7/integration/dns 2019/12/06 21:52:56 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt 2019/12/06 21:52:57 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt 2019/12/06 21:52:58 dns.go:424: resolving [{8.8.8.8.in-addr.arpa. 12 1}] failed: dns: overflow packing opt --- FAIL: TestDNS (3.01s) dns_test.go:38: exit status 9 FAIL FAIL github.com/rtr7/router7/integration/dns 3.011s FAIL ``` Not sure if the mistake is easy to spot, so let me know if you need more details.

i'll revert for the time being, thanks for your report.

[tmthrgd]

Let's make sure we include a test case (similar to whatever github.com/rtr7/router7/integration/dns is doing).

[tomponline]

@miekg we also experienced issues with this commit, but we worked around it with this fix: https://github.com/lxc/lxd/pull/6569

We're not sure if our original usage was wrong though.

[miekg]

[ Quoting <notifications@github.com> in "Re: [miekg/dns] regression: “dns: o..." ]

Let's make sure we include a test case (similar to whatever github.com/rtr7/router7/integration/dns is doing).

+1 The PR itself looked mostly harmless, so that can def. be improved.