# Regression (etcd #10998): a learner MUST grant a vote when asked, even though it still believes it
# is a learner — because the candidate's config is newer and already counts it as a voter. If such a
# "voter that doesn't know it yet" refused, a quorum-of-the-latest-config could be available yet the
# group would be stuck. Construction: bootstrap {1,2}, add node 3 as a learner and catch it up, then
# promote 3 to voter but isolate it so only {1,2} apply the promotion. With n1 "dead", n2 campaigns
# and asks n3 to vote; n3 (still a learner in its own view) must vote so n2 can win on {2,3}.
add-nodes 2 voters=(1,2)
----
n1: created voters={1,2} term=0 commit=0 last=0
n2: created voters={1,2} term=0 commit=0 last=0

campaign 1
----
n1 candidate term=1
RequestVote term=1 last=0/0 prevote=false

stabilize
----
> n2 recv RequestVote term=1 last=0/0 prevote=false
> n2 ready
  VoteResponse term=1 prevote=false reject=false
> n1 recv VoteResponse term=1 prevote=false reject=false
> n1 ready
  Heartbeat term=1 commit=0
  AppendEntries term=1 prev=0/0 commit=0 entries=[1/1 empty]
  n1 leader-changed term=1 lead=1
> n2 recv Heartbeat term=1 commit=0
> n2 recv AppendEntries term=1 prev=0/0 commit=0 entries=[1/1 empty]
> n2 ready
  HeartbeatResponse term=1
  AppendResponse term=1 match=1
  n2 leader-changed term=1 lead=1
> n1 recv HeartbeatResponse term=1
> n1 recv AppendResponse term=1 match=1
> n1 ready
  AppendEntries term=1 prev=0/0 commit=0 entries=[1/1 empty]
  AppendEntries term=1 prev=1/1 commit=1 entries=[]
> n2 recv AppendEntries term=1 prev=0/0 commit=0 entries=[1/1 empty]
> n2 recv AppendEntries term=1 prev=1/1 commit=1 entries=[]
> n2 ready
  AppendResponse term=1 match=1
  AppendResponse term=1 match=1
> n1 recv AppendResponse term=1 match=1
> n1 recv AppendResponse term=1 match=1

propose-conf-change 1 addlearner 3
----
n1 proposed conf-change addlearner n3 at index 2
AppendEntries term=1 prev=1/1 commit=1 entries=[1/2 conf-change 0x120c080212080300000000000000]

stabilize
----
> n2 recv AppendEntries term=1 prev=1/1 commit=1 entries=[1/2 conf-change 0x120c080212080300000000000000]
> n2 ready
  AppendResponse term=1 match=2
> n1 recv AppendResponse term=1 match=2
> n1 ready
  AppendEntries term=1 prev=1/2 commit=2 entries=[]
  n1 conf-changed index=2 voters={1,2} learners={3}
> n2 recv AppendEntries term=1 prev=1/2 commit=2 entries=[]
> n2 ready
  AppendResponse term=1 match=2
  n2 conf-changed index=2 voters={1,2} learners={3}
> n1 recv AppendResponse term=1 match=2

tick-heartbeat 1
----
Heartbeat term=1 commit=2
Heartbeat term=1 commit=0

stabilize
----
> n2 recv Heartbeat term=1 commit=2
> n3 recv Heartbeat term=1 commit=0
> n2 ready
  HeartbeatResponse term=1
> n3 ready
  HeartbeatResponse term=1
  n3 leader-changed term=1 lead=1
> n1 recv HeartbeatResponse term=1
> n1 recv HeartbeatResponse term=1
> n1 ready
  AppendEntries term=1 prev=1/2 commit=2 entries=[]
  AppendEntries term=1 prev=1/1 commit=2 entries=[1/2 conf-change 0x120c080212080300000000000000]
> n2 recv AppendEntries term=1 prev=1/2 commit=2 entries=[]
> n3 recv AppendEntries term=1 prev=1/1 commit=2 entries=[1/2 conf-change 0x120c080212080300000000000000]
> n2 ready
  AppendResponse term=1 match=2
> n3 ready
  AppendResponse term=1 reject hint=0/0
> n1 recv AppendResponse term=1 match=2
> n1 recv AppendResponse term=1 reject hint=0/0
> n1 ready
  AppendEntries term=1 prev=0/0 commit=2 entries=[1/1 empty, 1/2 conf-change 0x120c080212080300000000000000]
> n3 recv AppendEntries term=1 prev=0/0 commit=2 entries=[1/1 empty, 1/2 conf-change 0x120c080212080300000000000000]
> n3 ready
  AppendResponse term=1 match=2
  n3 conf-changed index=2 voters={1,2} learners={3}
> n1 recv AppendResponse term=1 match=2
> n1 ready
  AppendEntries term=1 prev=1/2 commit=2 entries=[]
> n3 recv AppendEntries term=1 prev=1/2 commit=2 entries=[]
> n3 ready
  AppendResponse term=1 match=2
> n1 recv AppendResponse term=1 match=2

isolate 3
----
n3 isolated

propose-conf-change 1 add 3
----
n1 proposed conf-change add n3 at index 3
AppendEntries term=1 prev=1/2 commit=2 entries=[1/3 conf-change 0x120a12080300000000000000]

stabilize
----
> n2 recv AppendEntries term=1 prev=1/2 commit=2 entries=[1/3 conf-change 0x120a12080300000000000000]
> n2 ready
  AppendResponse term=1 match=3
> n1 recv AppendResponse term=1 match=3
> n1 ready
  AppendEntries term=1 prev=1/3 commit=3 entries=[]
  n1 conf-changed index=3 voters={1,2,3}
> n2 recv AppendEntries term=1 prev=1/3 commit=3 entries=[]
> n2 ready
  AppendResponse term=1 match=3
  n2 conf-changed index=3 voters={1,2,3}
> n1 recv AppendResponse term=1 match=3

recover 3
----
n3 recovered

isolate 1
----
n1 isolated

campaign 2
----
n2 candidate term=2
RequestVote term=2 last=1/3 prevote=false
n2 leader-changed term=2 lead=none

stabilize
----
> n3 recv RequestVote term=2 last=1/3 prevote=false
> n3 ready
  VoteResponse term=2 prevote=false reject=false
  n3 leader-changed term=2 lead=none
> n2 recv VoteResponse term=2 prevote=false reject=false
> n2 ready
  Heartbeat term=2 commit=0
  AppendEntries term=2 prev=1/3 commit=3 entries=[2/4 empty]
  n2 leader-changed term=2 lead=2
> n3 recv Heartbeat term=2 commit=0
> n3 recv AppendEntries term=2 prev=1/3 commit=3 entries=[2/4 empty]
> n3 ready
  HeartbeatResponse term=2
  AppendResponse term=2 reject hint=1/2
  n3 leader-changed term=2 lead=2
> n2 recv HeartbeatResponse term=2
> n2 recv AppendResponse term=2 reject hint=1/2
> n2 ready
  AppendEntries term=2 prev=1/3 commit=3 entries=[2/4 empty]
  AppendEntries term=2 prev=1/2 commit=3 entries=[1/3 conf-change 0x120a12080300000000000000, 2/4 empty]
> n3 recv AppendEntries term=2 prev=1/3 commit=3 entries=[2/4 empty]
> n3 recv AppendEntries term=2 prev=1/2 commit=3 entries=[1/3 conf-change 0x120a12080300000000000000, 2/4 empty]
> n3 ready
  AppendResponse term=2 reject hint=1/2
  AppendResponse term=2 match=4
  n3 conf-changed index=3 voters={1,2,3}
> n2 recv AppendResponse term=2 reject hint=1/2
> n2 recv AppendResponse term=2 match=4
> n2 ready
  AppendEntries term=2 prev=1/1 commit=3 entries=[1/2 conf-change 0x120c080212080300000000000000, 1/3 conf-change 0x120a12080300000000000000, 2/4 empty]
  AppendEntries term=2 prev=2/4 commit=4 entries=[]
> n3 recv AppendEntries term=2 prev=1/1 commit=3 entries=[1/2 conf-change 0x120c080212080300000000000000, 1/3 conf-change 0x120a12080300000000000000, 2/4 empty]
> n3 recv AppendEntries term=2 prev=2/4 commit=4 entries=[]
> n3 ready
  AppendResponse term=2 match=4
  AppendResponse term=2 match=4
> n2 recv AppendResponse term=2 match=4
> n2 recv AppendResponse term=2 match=4

raft-state
----
n1: leader term=1 lead=1
n2: leader term=2 lead=2
n3: follower term=2 lead=2

