#!/bin/sh

test_description='test skipping fetch negotiator'
. ./test-lib.sh

have_sent () {
        while test "$#" -ne 0
        do
                grep "fetch> have $(git -C client rev-parse $1)" trace
                if test $? -ne 0
                then
                        echo "No have $(git -C client rev-parse $1) ($1)"
                        return 1
                fi
                shift
        done
}

have_not_sent () {
        while test "$#" -ne 0
        do
                grep "fetch> have $(git -C client rev-parse $1)" trace
                if test $? -eq 0
                then
                        return 1
                fi
                shift
        done
}

# trace_fetch <client_dir> <server_dir> [args]
#
# Trace the packet output of fetch, but make sure we disable the variable
# in the child upload-pack, so we don't combine the results in the same file.
trace_fetch () {
        client=$1; shift
        server=$1; shift
        GIT_TRACE_PACKET="$(pwd)/trace" \
        git -C "$client" fetch \
          --upload-pack 'unset GIT_TRACE_PACKET; git-upload-pack' \
          "$server" "$@"
}

test_expect_success 'commits with no parents are sent regardless of skip distance' '
        git init server &&
        test_commit -C server to_fetch &&

        git init client &&
        for i in $(test_seq 7)
        do
                test_commit -C client c$i
        done &&

        # We send: "c7" (skip 1) "c5" (skip 2) "c2" (skip 4). After that, since
        # "c1" has no parent, it is still sent as "have" even though it would
        # normally be skipped.
        test_config -C client fetch.negotiationalgorithm skipping &&
        trace_fetch client "$(pwd)/server" &&
        have_sent c7 c5 c2 c1 &&
        have_not_sent c6 c4 c3
'

test_expect_success 'unknown fetch.negotiationAlgorithm values error out' '
        rm -rf server client trace &&
        git init server &&
        test_commit -C server to_fetch &&

        git init client &&
        test_commit -C client on_client &&
        git -C client checkout on_client &&

        test_config -C client fetch.negotiationAlgorithm invalid &&
        test_must_fail git -C client fetch "$(pwd)/server" 2>err &&
        test_i18ngrep "unknown fetch negotiation algorithm" err &&

        # Explicit "default" value
        test_config -C client fetch.negotiationAlgorithm default &&
        git -C client -c fetch.negotiationAlgorithm=default fetch "$(pwd)/server" &&

        # Implementation detail: If there is nothing to fetch, we will not error out
        test_config -C client fetch.negotiationAlgorithm invalid &&
        git -C client fetch "$(pwd)/server" 2>err &&
        test_i18ngrep ! "unknown fetch negotiation algorithm" err
'

test_expect_success 'when two skips collide, favor the larger one' '
        rm -rf server client trace &&
        git init server &&
        test_commit -C server to_fetch &&

        git init client &&
        for i in $(test_seq 11)
        do
                test_commit -C client c$i
        done &&
        git -C client checkout c5 &&
        test_commit -C client c5side &&

        # Before reaching c5, we send "c5side" (skip 1) and "c11" (skip 1) "c9"
        # (skip 2) "c6" (skip 4). The larger skip (skip 4) takes precedence, so
        # the next "have" sent will be "c1" (from "c6" skip 4) and not "c4"
        # (from "c5side" skip 1).
        test_config -C client fetch.negotiationalgorithm skipping &&
        trace_fetch client "$(pwd)/server" &&
        have_sent c5side c11 c9 c6 c1 &&
        have_not_sent c10 c8 c7 c5 c4 c3 c2
'

test_expect_success 'use ref advertisement to filter out commits' '
        rm -rf server client trace &&
        git init server &&
        test_commit -C server c1 &&
        test_commit -C server c2 &&
        test_commit -C server c3 &&
        git -C server tag -d c1 c2 c3 &&

        git clone server client &&
        test_commit -C client c4 &&
        test_commit -C client c5 &&
        git -C client checkout c4^^ &&
        test_commit -C client c2side &&

        git -C server checkout --orphan anotherbranch &&
        test_commit -C server to_fetch &&

        # The server advertising "c3" (as "refs/heads/master") means that we do
        # not need to send any ancestors of "c3", but we still need to send "c3"
        # itself.
        test_config -C client fetch.negotiationalgorithm skipping &&
        trace_fetch client origin to_fetch &&
        have_sent c5 c4^ c2side &&
        have_not_sent c4 c4^^ c4^^^
'

test_expect_success 'handle clock skew' '
        rm -rf server client trace &&
        git init server &&
        test_commit -C server to_fetch &&

        git init client &&

        # 2 regular commits
        test_tick=2000000000 &&
        test_commit -C client c1 &&
        test_commit -C client c2 &&

        # 4 old commits
        test_tick=1000000000 &&
        git -C client checkout c1 &&
        test_commit -C client old1 &&
        test_commit -C client old2 &&
        test_commit -C client old3 &&
        test_commit -C client old4 &&

        # "c2" and "c1" are popped first, then "old4" to "old1". "old1" would
        # normally be skipped, but is treated as a commit without a parent here
        # and sent, because (due to clock skew) its only parent has already been
        # popped off the priority queue.
        test_config -C client fetch.negotiationalgorithm skipping &&
        trace_fetch client "$(pwd)/server" &&
        have_sent c2 c1 old4 old2 old1 &&
        have_not_sent old3
'

test_expect_success 'do not send "have" with ancestors of commits that server ACKed' '
        rm -rf server client trace &&
        git init server &&
        test_commit -C server to_fetch &&

        git init client &&
        for i in $(test_seq 8)
        do
                git -C client checkout --orphan b$i &&
                test_commit -C client b$i.c0
        done &&
        for j in $(test_seq 19)
        do
                for i in $(test_seq 8)
                do
                        git -C client checkout b$i &&
                        test_commit -C client b$i.c$j
                done
        done &&

        # Copy this branch over to the server and add a commit on it so that it
        # is reachable but not advertised.
        git -C server fetch --no-tags "$(pwd)/client" b1:refs/heads/b1 &&
        git -C server checkout b1 &&
        test_commit -C server commit-on-b1 &&

        test_config -C client fetch.negotiationalgorithm skipping &&
        trace_fetch client "$(pwd)/server" to_fetch &&
        grep "  fetch" trace &&

        # fetch-pack sends 2 requests each containing 16 "have" lines before
        # processing the first response. In these 2 requests, 4 commits from
        # each branch are sent. Just check the first branch.
        have_sent b1.c19 b1.c17 b1.c14 b1.c9 &&
        have_not_sent b1.c18 b1.c16 b1.c15 b1.c13 b1.c12 b1.c11 b1.c10 &&

        # While fetch-pack is processing the first response, it should read that
        # the server ACKs b1.c19 and b1.c17.
        grep "fetch< ACK $(git -C client rev-parse b1.c19) common" trace &&
        grep "fetch< ACK $(git -C client rev-parse b1.c17) common" trace &&

        # fetch-pack should thus not send any more commits in the b1 branch, but
        # should still send the others (in this test, just check b2).
        for i in $(test_seq 0 8)
        do
                have_not_sent b1.c$i
        done &&
        have_sent b2.c1 b2.c0
'

test_done