Fallback to the default error format when a file is empty

[williamthome]

This change resolves a bad match error that occurs when a .erl file is empty by falling back to the default error format.

Before

===> Task failed: {{badmatch,[]},
                              [{rebar_compiler_format,colorize,2,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_compiler_format.erl"},
                                 {line,74}]},
                               {rebar_compiler_format,format,5,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_compiler_format.erl"},
                                 {line,25}]},
                               {rebar_base_compiler,
                                '-format_errors/4-lc$^1/1-1-',4,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_base_compiler.erl"},
                                 {line,278}]},
                               {rebar_base_compiler,
                                '-format_errors/4-lc$^0/1-0-',3,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_base_compiler.erl"},
                                 {line,278}]},
                               {rebar_base_compiler,error_tuple,5,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_base_compiler.erl"},
                                 {line,160}]},
                               {rebar_compiler,compile_worker,2,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_compiler.erl"},
                                 {line,337}]},
                               {rebar_parallel,worker,3,
                                [{file,
                                  "/home/runner/work/rebar3/rebar3/apps/rebar/src/rebar_parallel.erl"},
                                 {line,260}]}]}

After

===> Compiling src/r3_colorize_bug.erl failed
src/r3_colorize_bug.erl:1:1: no module definition

[ferd]

Suggested change

	try
	case file:read_file(Source) of
	{ok, <<>>} ->
	{error, empty_file};
	{ok, Bin} ->
	Splits = re:split(Bin, "(?:\n|\r\n|\r)", [{newline, anycrlf}]),
	{ok, lists:nth(Nth, Splits)};
	{error, Reason} ->
	{error, Reason}
	end
	try file:read_file(Source) of
	{ok, <<>>} ->
	{error, empty_file};
	{ok, Bin} ->
	Splits = re:split(Bin, "(?:\n|\r\n|\r)", [{newline, anycrlf}]),
	{ok, lists:nth(Nth, Splits)};
	{error, Reason} ->
	{error, Reason}

This might give you similar semantics but a cleaner result, although it won't capture errors in re:split or lists:nth anymore, so we can maybe disregard this.

[williamthome]

Removed the try/catch in ff987ad

[williamthome]

Tests are failing now. It seems we need the try/catch here to prevent a crash. I'll push a fix.

[williamthome]

Fixed in e383d3b

[ferd]

Nice catch!