#!/bin/sh

test_description='commit graph'
. ./test-lib.sh

test_expect_success 'setup full repo' '
        mkdir full &&
        cd "$TRASH_DIRECTORY/full" &&
        git init &&
        git config core.commitGraph true &&
        objdir=".git/objects"
'

test_expect_success 'verify graph with no graph file' '
        cd "$TRASH_DIRECTORY/full" &&
        git commit-graph verify
'

test_expect_success 'write graph with no packs' '
        cd "$TRASH_DIRECTORY/full" &&
        git commit-graph write --object-dir . &&
        test_path_is_file info/commit-graph
'

test_expect_success 'create commits and repack' '
        cd "$TRASH_DIRECTORY/full" &&
        for i in $(test_seq 3)
        do
                test_commit $i &&
                git branch commits/$i
        done &&
        git repack
'

graph_git_two_modes() {
        git -c core.commitGraph=true $1 >output
        git -c core.commitGraph=false $1 >expect
        test_cmp output expect
}

graph_git_behavior() {
        MSG=$1
        DIR=$2
        BRANCH=$3
        COMPARE=$4
        test_expect_success "check normal git operations: $MSG" '
                cd "$TRASH_DIRECTORY/$DIR" &&
                graph_git_two_modes "log --oneline $BRANCH" &&
                graph_git_two_modes "log --topo-order $BRANCH" &&
                graph_git_two_modes "log --graph $COMPARE..$BRANCH" &&
                graph_git_two_modes "branch -vv" &&
                graph_git_two_modes "merge-base -a $BRANCH $COMPARE"
        '
}

graph_git_behavior 'no graph' full commits/3 commits/1

graph_read_expect() {
        OPTIONAL=""
        NUM_CHUNKS=3
        if test ! -z $2
        then
                OPTIONAL=" $2"
                NUM_CHUNKS=$((3 + $(echo "$2" | wc -w)))
        fi
        cat >expect <<- EOF
        header: 43475048 1 1 $NUM_CHUNKS 0
        num_commits: $1
        chunks: oid_fanout oid_lookup commit_metadata$OPTIONAL
        EOF
        git commit-graph read >output &&
        test_cmp expect output
}

test_expect_success 'write graph' '
        cd "$TRASH_DIRECTORY/full" &&
        graph1=$(git commit-graph write) &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "3"
'

graph_git_behavior 'graph exists' full commits/3 commits/1

test_expect_success 'Add more commits' '
        cd "$TRASH_DIRECTORY/full" &&
        git reset --hard commits/1 &&
        for i in $(test_seq 4 5)
        do
                test_commit $i &&
                git branch commits/$i
        done &&
        git reset --hard commits/2 &&
        for i in $(test_seq 6 7)
        do
                test_commit $i &&
                git branch commits/$i
        done &&
        git reset --hard commits/2 &&
        git merge commits/4 &&
        git branch merge/1 &&
        git reset --hard commits/4 &&
        git merge commits/6 &&
        git branch merge/2 &&
        git reset --hard commits/3 &&
        git merge commits/5 commits/7 &&
        git branch merge/3 &&
        git repack
'

# Current graph structure:
#
#   __M3___
#  /   |   \
# 3 M1 5 M2 7
# |/  \|/  \|
# 2    4    6
# |___/____/
# 1

test_expect_success 'write graph with merges' '
        cd "$TRASH_DIRECTORY/full" &&
        git commit-graph write &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "10" "large_edges"
'

graph_git_behavior 'merge 1 vs 2' full merge/1 merge/2
graph_git_behavior 'merge 1 vs 3' full merge/1 merge/3
graph_git_behavior 'merge 2 vs 3' full merge/2 merge/3

test_expect_success 'Add one more commit' '
        cd "$TRASH_DIRECTORY/full" &&
        test_commit 8 &&
        git branch commits/8 &&
        ls $objdir/pack | grep idx >existing-idx &&
        git repack &&
        ls $objdir/pack| grep idx | grep -v --file=existing-idx >new-idx
'

# Current graph structure:
#
#      8
#      |
#   __M3___
#  /   |   \
# 3 M1 5 M2 7
# |/  \|/  \|
# 2    4    6
# |___/____/
# 1

graph_git_behavior 'mixed mode, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'mixed mode, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'write graph with new commit' '
        cd "$TRASH_DIRECTORY/full" &&
        git commit-graph write &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "11" "large_edges"
'

graph_git_behavior 'full graph, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'full graph, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'write graph with nothing new' '
        cd "$TRASH_DIRECTORY/full" &&
        git commit-graph write &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "11" "large_edges"
'

graph_git_behavior 'cleared graph, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'cleared graph, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'build graph from latest pack with closure' '
        cd "$TRASH_DIRECTORY/full" &&
        cat new-idx | git commit-graph write --stdin-packs &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "9" "large_edges"
'

graph_git_behavior 'graph from pack, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'graph from pack, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'build graph from commits with closure' '
        cd "$TRASH_DIRECTORY/full" &&
        git tag -a -m "merge" tag/merge merge/2 &&
        git rev-parse tag/merge >commits-in &&
        git rev-parse merge/1 >>commits-in &&
        cat commits-in | git commit-graph write --stdin-commits &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "6"
'

graph_git_behavior 'graph from commits, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'graph from commits, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'build graph from commits with append' '
        cd "$TRASH_DIRECTORY/full" &&
        git rev-parse merge/3 | git commit-graph write --stdin-commits --append &&
        test_path_is_file $objdir/info/commit-graph &&
        graph_read_expect "10" "large_edges"
'

graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
graph_git_behavior 'append graph, commit 8 vs merge 2' full commits/8 merge/2

test_expect_success 'setup bare repo' '
        cd "$TRASH_DIRECTORY" &&
        git clone --bare --no-local full bare &&
        cd bare &&
        git config core.commitGraph true &&
        baredir="./objects"
'

graph_git_behavior 'bare repo, commit 8 vs merge 1' bare commits/8 merge/1
graph_git_behavior 'bare repo, commit 8 vs merge 2' bare commits/8 merge/2

test_expect_success 'write graph in bare repo' '
        cd "$TRASH_DIRECTORY/bare" &&
        git commit-graph write &&
        test_path_is_file $baredir/info/commit-graph &&
        graph_read_expect "11" "large_edges"
'

graph_git_behavior 'bare repo with graph, commit 8 vs merge 1' bare commits/8 merge/1
graph_git_behavior 'bare repo with graph, commit 8 vs merge 2' bare commits/8 merge/2

test_expect_success 'perform fast-forward merge in full repo' '
        cd "$TRASH_DIRECTORY/full" &&
        git checkout -b merge-5-to-8 commits/5 &&
        git merge commits/8 &&
        git show-ref -s merge-5-to-8 >output &&
        git show-ref -s commits/8 >expect &&
        test_cmp expect output
'

# the verify tests below expect the commit-graph to contain
# exactly the commits reachable from the commits/8 branch.
# If the file changes the set of commits in the list, then the
# offsets into the binary file will result in different edits
# and the tests will likely break.

test_expect_success 'git commit-graph verify' '
        cd "$TRASH_DIRECTORY/full" &&
        git rev-parse commits/8 | git commit-graph write --stdin-commits &&
        git commit-graph verify >output
'

NUM_COMMITS=9
HASH_LEN=20
GRAPH_BYTE_VERSION=4
GRAPH_BYTE_HASH=5
GRAPH_BYTE_CHUNK_COUNT=6
GRAPH_CHUNK_LOOKUP_OFFSET=8
GRAPH_CHUNK_LOOKUP_WIDTH=12
GRAPH_CHUNK_LOOKUP_ROWS=5
GRAPH_BYTE_OID_FANOUT_ID=$GRAPH_CHUNK_LOOKUP_OFFSET
GRAPH_BYTE_OID_LOOKUP_ID=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
                            1 * $GRAPH_CHUNK_LOOKUP_WIDTH))
GRAPH_BYTE_COMMIT_DATA_ID=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
                             2 * $GRAPH_CHUNK_LOOKUP_WIDTH))
GRAPH_FANOUT_OFFSET=$(($GRAPH_CHUNK_LOOKUP_OFFSET + \
                       $GRAPH_CHUNK_LOOKUP_WIDTH * $GRAPH_CHUNK_LOOKUP_ROWS))
GRAPH_BYTE_FANOUT1=$(($GRAPH_FANOUT_OFFSET + 4 * 4))
GRAPH_BYTE_FANOUT2=$(($GRAPH_FANOUT_OFFSET + 4 * 255))
GRAPH_OID_LOOKUP_OFFSET=$(($GRAPH_FANOUT_OFFSET + 4 * 256))
GRAPH_BYTE_OID_LOOKUP_ORDER=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * 8))
GRAPH_BYTE_OID_LOOKUP_MISSING=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * 4 + 10))
GRAPH_COMMIT_DATA_OFFSET=$(($GRAPH_OID_LOOKUP_OFFSET + $HASH_LEN * $NUM_COMMITS))
GRAPH_BYTE_COMMIT_TREE=$GRAPH_COMMIT_DATA_OFFSET

# usage: corrupt_graph_and_verify <position> <data> <string>
# Manipulates the commit-graph file at the position
# by inserting the data, then runs 'git commit-graph verify'
# and places the output in the file 'err'. Test 'err' for
# the given string.
corrupt_graph_and_verify() {
        pos=$1
        data="${2:-\0}"
        grepstr=$3
        cd "$TRASH_DIRECTORY/full" &&
        test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
        cp $objdir/info/commit-graph commit-graph-backup &&
        printf "$data" | dd of="$objdir/info/commit-graph" bs=1 seek="$pos" conv=notrunc &&
        test_must_fail git commit-graph verify 2>test_err &&
        grep -v "^+" test_err >err
        test_i18ngrep "$grepstr" err
}

test_expect_success 'detect bad signature' '
        corrupt_graph_and_verify 0 "\0" \
                "graph signature"
'

test_expect_success 'detect bad version' '
        corrupt_graph_and_verify $GRAPH_BYTE_VERSION "\02" \
                "graph version"
'

test_expect_success 'detect bad hash version' '
        corrupt_graph_and_verify $GRAPH_BYTE_HASH "\02" \
                "hash version"
'

test_expect_success 'detect low chunk count' '
        corrupt_graph_and_verify $GRAPH_BYTE_CHUNK_COUNT "\02" \
                "missing the .* chunk"
'

test_expect_success 'detect missing OID fanout chunk' '
        corrupt_graph_and_verify $GRAPH_BYTE_OID_FANOUT_ID "\0" \
                "missing the OID Fanout chunk"
'

test_expect_success 'detect missing OID lookup chunk' '
        corrupt_graph_and_verify $GRAPH_BYTE_OID_LOOKUP_ID "\0" \
                "missing the OID Lookup chunk"
'

test_expect_success 'detect missing commit data chunk' '
        corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_DATA_ID "\0" \
                "missing the Commit Data chunk"
'

test_expect_success 'detect incorrect fanout' '
        corrupt_graph_and_verify $GRAPH_BYTE_FANOUT1 "\01" \
                "fanout value"
'

test_expect_success 'detect incorrect fanout final value' '
        corrupt_graph_and_verify $GRAPH_BYTE_FANOUT2 "\01" \
                "fanout value"
'

test_expect_success 'detect incorrect OID order' '
        corrupt_graph_and_verify $GRAPH_BYTE_OID_LOOKUP_ORDER "\01" \
                "incorrect OID order"
'

test_expect_success 'detect OID not in object database' '
        corrupt_graph_and_verify $GRAPH_BYTE_OID_LOOKUP_MISSING "\01" \
                "from object database"
'

test_expect_success 'detect incorrect tree OID' '
        corrupt_graph_and_verify $GRAPH_BYTE_COMMIT_TREE "\01" \
                "root tree OID for commit"
'

test_done