[revparse] Troubleshooting the probing logic

revparse-probe.sh

#!/bin/sh

retrieve_head() {
	local oid=$(git reflog HEAD@{0} -n 1 --format=format:%H);
	echo "$oid"
}

add_commit() {
	echo "$1" > file.txt
	git add .
	git commit -m "$1" > /dev/null
	
	echo "$(retrieve_head)"
}

init() {
	rm -rf ./revparse-probe-repo
	mkdir revparse-probe-repo && cd revparse-probe-repo
	git init .

	commit_oid=$(add_commit Commit)
	branch_target=$(add_commit Branch)
	tag_target=$(add_commit Tag)
	symref_target=$(add_commit Symref)

	echo $symref_target > ./.git/refs/heads/symtarget

	initial_head=$(retrieve_head)
}

create_symref() {
	echo "ref: refs/heads/symtarget" > "./.git/$1"
}

create_tag() {
	echo $tag_target > "./.git/refs/tags/$1"
}

create_branch() {
	echo $branch_target > "./.git/refs/heads/$1"
}

# $1 = commit-ish
# $2 = expected
# $3 = current
# $4 = operation
# $5 = message
check_result() {
	if [ "$2" != "$3" ]; then
		echo "fail - $4 $1 (expected: $2 - retrieved: $3)"
	else
		echo "$5"
	fi
}

test_checkout()  {
	git checkout -f -q "$1"

	local head=$(retrieve_head)
	check_result "$1" "$2" "$head" "chekout" "$3"
}

test_reset()  {
	git reset --hard -q "$1"

	local head=$(retrieve_head)
	check_result "$1" "$2" "$head" "reset" "$3"
}

test_log() {
	local oid=$(git log $1 -n 1 --format=format:%H)

	check_result "$1" "$2" "$oid" "log" "$3"
}

cleanup() {
	rm -rf "./.git/refs/heads/$commit_oid"
	rm -rf "./.git/refs/tags/$commit_oid"
	rm -rf "./.git/$commit_oid"

	echo "$commit_oid" > "./.git/refs/heads/master"
	echo "ref: refs/heads/master" > "./.git/HEAD"
	git reset --hard -q
}

init

echo "Commit: $commit_oid";
echo "Branch target: $branch_target";
echo "Tag target: $tag_target";
echo "Symref target: $symref_target";
echo "HEAD: $(retrieve_head)"
echo

test_checkout $commit_oid $commit_oid "Can checkout an oid"
cleanup

create_symref "$commit_oid"
create_tag "$commit_oid"
test_checkout $commit_oid $commit_oid "Can checkout an oid even if there's a symref and a tag with the same name"

create_branch "$commit_oid"
test_checkout $commit_oid $branch_target "Can checkout a branch even if there's an oid, a tag and a symref with the same name"
cleanup

test_reset $commit_oid $commit_oid "Can reset to an oid"
cleanup

create_symref "$commit_oid"
create_tag "$commit_oid"
create_branch "$commit_oid"

test_reset $commit_oid $commit_oid "Can reset to an oid even if there's a symref, a branch and a tag with the same name"
test_log $commit_oid $commit_oid "Can log to an oid even if there's a symref, a branch and a tag with the same name"
cleanup

create_branch "deadbeef"
test_log "deadbeef" $branch_target "Can log to a branch"

create_tag "deadbeef"
test_log "deadbeef" $tag_target "Can log to a tag even if there's a branch with the same name"

create_symref "deadbeef"
test_log "deadbeef" $symref_target "Can log to a symref even if there's a branch and a tag with the same name"