Return Request context cancelled error

[aarshkshah1992]

As discussed, if the user's request context is cancelled for whatever reason, we should write that error to the reponse error channel.

@hannahhoward Because we ignore context cancellation errors here:

go-graphsync/requestmanager/executor/executor.go

Line 148 in d88611c

if !isContextErr(err) {

we had a race wherein we'd mark a request as "completed" even though the context is cancelled because we close the response error channel here without writing anything to it. Have fixed that as well.

LMKWYT.

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[aarshkshah1992]

@hannahhoward The test that is failing on the CI succeeds locally for me a 100 times:

aarshshah@Aarshs-MacBook-Pro requestmanager % go test -race -count 100 -run TestLocallyFulfilledFirstRequestSucceedsLater
PASS
ok  	github.com/ipfs/go-graphsync/requestmanager	0.939s

Is this a known flaky test ?

[hannahhoward]

LGTM - don't worry about that test, yes that one particular test is flaky and I've been unable to fix it from being that way. apologies.