getsidechaininfo rpc help incorrectly specifies the order of current_fedpegscripts array #1201
Description
The help for the getsidechaininfo RPC says "Oldest first" in
...
"fedpegscript" : "hex", (string) The fedpegscript from genesis block
"current_fedpegscripts" : [ (json array) The currently-enforced fedpegscripts in hex. Peg-ins for any entries on this list are honored by consensus and policy. Oldest first. Two total entries are possible
"hex", (string) active fedpegscript
...
],
"current_fedpeg_programs" : [ (json array) The currently-enforced fedpegscript scriptPubKeys in hex. Prior to a transition this may be P2SH scriptpubkey, otherwise it will be a native segwit script. Results are paired in-order with current_fedpegscripts
"hex", (string) active fedpegscript scriptPubKeys
...
],
but the array appears to be newest first.
The result of running this command in prod just after the DynaFed WM transition is (output elided)
"fedpegscript": "745c87635b2102...5bb5368ae",
"current_fedpeg_programs": [
"0020333a4af67452308b9814ff59dc2fc3d0325fd7fdcb61d108e992b3956095f2fe",
"a9149e10aa3d2f248e0e42f9bab31e858240e7ed40e487"
],
"current_fedpegscripts": [
"5b21020e0338c96a8....ca5bb53ae68",
"745c87635b21020e0.......a5bb5368ae"
....
Note that the genesis block fedpegscript `745...` is listed second.
getblockchaininfo reports
{
"chain": "liquidv1",
"blocks": 2199553,
...
"current_fedpeg_program": "0020333a4af67452308b9814ff59dc2fc3d0325fd7fdcb61d108e992b3956095f2fe",
"current_fedpeg_script": "5b21020e0338c96a...
The implementation walks backwards through the blocks at https://github.com/ElementsProject/elements/blob/master/src/pegins.cpp#L476
If a program uses (and caches) an expiring fedpegscript, it may result in invalid peg-in addresses being generated.