pin add hangs on a particular cbor object

[ianopolous]

Version information:

go-ipfs version: 0.4.5-rc1-313b884
Repo version: 5
System version: amd64/linux
Golang version: go1.7.1

Type: Bug

Priority: P0

Description:

pin add hangs. A minimal repro is:

printf "\x4b\x67\x27\x64\x61\x79\x20\x49\x50\x46\x53\x21" | ipfs block put --format=cbor
=> zdpuAsFzbmVjkDjySRJNAw2ndtAogPUVqCSZgP4MhxVRxVcE4
printf "\xa2\x65\x61\x6c\x69\x6e\x6b\xd8\x2a\x58\x25\x00\x01\x71\x12\x20\x65\x96\x50\xfc\x34\x43\xc9\x16\x42\x80\x48\xef\xc5\xba\x45\x58\xdc\x86\x35\x94\x98\x0a\x59\xf5\xcb\x3c\x4d\x84\x86\x7e\x6d\x31\x63\x61\x72\x72\x80" | ipfs block put --format=cbor
=> zdpuAq6Q29ycu5frDQ9kkUf2HHhNWNgCQtyUZUWZBP1423vvn
ipfs pin add -r zdpuAq6Q29ycu5frDQ9kkUf2HHhNWNgCQtyUZUWZBP1423vvn

The pin hangs.
The first object is just a cbor byte[] of "g'day IPFS!"
The second is a cbor map with 2 elements, a merkle link, and an empty cbor list:
{
"alink":"zdpuAsFzbmVjkDjySRJNAw2ndtAogPUVqCSZgP4MhxVRxVcE4",
"arr:[]
}

ipfs dag get on the second object gives:
{"alink":"zdpuAsFzbmVjkDjySRJNAw2ndtAogPUVqCSZgP4MhxVRxVcE4","arr":null}
Not sure why the empty list has become null..

[ianopolous]

I forgot to add that removing either of the elements in the map makes the pin succeed. E.g. removing the cbor list

# same first command, then
printf "\xa1\x65\x61\x6c\x69\x6e\x6b\xd8\x2a\x58\x25\x00\x01\x71\x12\x20\x65\x96\x50\xfc\x34\x43\xc9\x16\x42\x80\x48\xef\xc5\xba\x45\x58\xdc\x86\x35\x94\x98\x0a\x59\xf5\xcb\x3c\x4d\x84\x86\x7e\x6d\x31" | ipfs block put --format=cbor
=> zdpuAnhb9rC4Mw8G1QcsJK7TJB6QW6d1JR5VUWcUU16muTbdf
ipfs pin add -r zdpuAnhb9rC4Mw8G1QcsJK7TJB6QW6d1JR5VUWcUU16muTbdf

[ianopolous]

After #3666 this is still the same except the conversion from [] to null in dag get is fixed.

[ianopolous]

This is fixed by ensuring our map keys are ordered by cbor canonical order (which is NOT lexicographic order - shorter keys are first)