#!/bin/bash
# usage:
#    ./update-cargo-metadata
# copies from toplevel Cargo.toml to others
# the part copied is the paragraph which starts with version=

set -e

fail () { echo >&2 "${0##*/}: error: $*"; exit 12; }

[ $# = 0 ] || fail "bad usage"

files=$(git ls-files :\*/Cargo.toml :Cargo.toml)

for f in $files; do
    perl -i~ -pe '
	BEGIN {
            $/ = "\n\n";
	    open I, "Cargo.toml" or die $!;
	    our $re = qr{^version\s*\=};
            our $std;
	    while (<I>) {
		next unless m{$re};
		$std = $_;
		last;
	    }
	    die "not found in ./Cargo.toml" unless defined $std;
#	    $std =~ s{\s*$}{};
	}

	next unless m{$re};
	next if $y++;
#	s{\s*$}{};;
#	$_ = $std.$&;
	$_ = $std;
	END {
	    $y or die "not found in '$f'";
	}
    ' $f
done

echo "working tree file(s) maybe updated, check with git."