: included from 6002 and others

mkdir -p .git/refs/tags

>sed.script

# Answer the sha1 has associated with the tag. The tag must exist in .git/refs/tags
proc tag {
	setglobal _tag = $1
	test -f ".git/refs/tags/$_tag" || error "tag: \"$_tag\" does not exist"
	cat ".git/refs/tags/$_tag"
}

# Generate a commit using the text specified to make it unique and the tree
# named by the tag specified.
proc unique_commit {
	setglobal _text = $1
	setglobal _tree = $2
	shift 2
	echo $_text | git commit-tree $[tag $_tree] @Argv
}

# Save the output of a command into the tag specified. Prepend
# a substitution script for the tag onto the front of sed.script
proc save_tag {
	setglobal _tag = $1
	test -n $_tag || error "usage: save_tag tag commit-args ..."
	shift 1
	@Argv >".git/refs/tags/$_tag"

	echo "s/$[tag $_tag]/$_tag/g" >sed.script.tmp
	cat sed.script >>sed.script.tmp
	rm sed.script
	mv sed.script.tmp sed.script
}

# Replace unhelpful sha1 hashes with their symbolic equivalents
proc entag {
	sed -f sed.script
}

# Execute a command after first saving, then setting the GIT_AUTHOR_EMAIL
# tag to a specified value. Restore the original value on return.
proc as_author {
	setglobal _author = $1
	shift 1
	setglobal _save = $GIT_AUTHOR_EMAIL

	setglobal GIT_AUTHOR_EMAIL = $_author
	export GIT_AUTHOR_EMAIL
	@Argv
	if test -z $_save
	{
		unset GIT_AUTHOR_EMAIL
	} else {
		setglobal GIT_AUTHOR_EMAIL = $_save
		export GIT_AUTHOR_EMAIL
	}
}

proc commit_date {
	setglobal _commit = $1
	git cat-file commit $_commit |
	sed -n "s/^committer .*> \([0-9]*\) .*/\1/p"
}

# Assign the value of fake date to a variable, but
# allow fairly common "1971-08-16 00:00" to be omittd
proc assign_fake_date {
	match $2 {
	with ??:??:??	eval "$1='1971-08-16 $2'" 
	with ??:??		eval "$1='1971-08-16 00:$2'" 
	with ??		eval "$1='1971-08-16 00:00:$2'" 
	with *		eval "$1='$2'" 
	}
}

proc on_committer_date {
	assign_fake_date GIT_COMMITTER_DATE $1
	export GIT_COMMITTER_DATE
	shift 1
	@Argv
}

proc on_dates {
	assign_fake_date GIT_COMMITTER_DATE $1
	assign_fake_date GIT_AUTHOR_DATE $2
	export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
	shift 2
	@Argv
}

# Execute a command and suppress any error output.
proc hide_error {
	@Argv !2 >/dev/null
}

proc check_output {
	setglobal _name = $1
	shift 1
	if eval "$ifsjoin(Argv)" | entag >"$_name.actual"
	{
		test_cmp "$_name.expected" "$_name.actual"
	} else {
		return 1
	}
}

# Turn a reasonable test description into a reasonable test name.
# All alphanums translated into -'s which are then compressed and stripped
# from front and back.
proc name_from_description {
	perl -pe '
		s/[^A-Za-z0-9.]/-/g;
		s/-+/-/g;
		s/-$//;
		s/^-//;
		y/A-Z/a-z/;
	'
}


# Execute the test described by the first argument, by eval'ing
# command line specified in the 2nd argument. Check the status code
# is zero and that the output matches the stream read from
# stdin.
proc test_output_expect_success
{
	setglobal _description = $1
	setglobal _test = $2
	test $Argc -eq 2 ||
	error "usage: test_output_expect_success description test <<EOF ... EOF"

	setglobal _name = $[echo $_description | name_from_description]
	cat >"$_name.expected"
	test_expect_success $_description "check_output $_name \"$_test\""
}