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Description
Some (somewhat reasonable?) mistakes lead to completely incomprehensible and unhelpful compiler errors. For example, writing
#[arg("--time[X]")] // WRONG!
IgnoreOptionArg(#[allow(dead_code)] Option<OsString>),
instead of:
#[arg("--time[=X]")] // CORRECT!
IgnoreOptionArg(#[allow(dead_code)] Option<OsString>),
leads to this unhelpful error message:
error: proc-macro derive panicked
--> src/uu/du/src/du.rs:79:10
|
79 | #[derive(Arguments)]
| ^^^^^^^^^
|
= help: message: called `Option::unwrap()` on a `None` value
How should we approach this? I suggest replacing every .unwrap within derive to a .expect. This way, we at least get some information on what's wrong. This affects the following places:
$ git grep -Pirn 'unwrap\(' derive/
derive/src/argument.rs:35: return ArgumentsAttr::parse(attr).unwrap();
derive/src/argument.rs:43: let attributes = get_arg_attributes(&v.attrs).unwrap();
derive/src/flags.rs:64: .unwrap();
derive/src/flags.rs:86: let f = chars.next().unwrap();
derive/src/help.rs:88: ).unwrap();
derive/src/help.rs:90: writeln!(w, "{}", #summary).unwrap();
derive/src/help.rs:92: writeln!(w, "\nUsage:\n {}", format!(#usage, bin_name)).unwrap();
derive/src/help.rs:96: writeln!(w, "{}", #after_options).unwrap();
derive/src/help.rs:103: let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
derive/src/help.rs:107: let mut f = std::fs::File::open(location).unwrap();
derive/src/help.rs:108: f.read_to_string(&mut contents).unwrap();
derive/src/help_parser.rs:117: parse_section("some section", input).unwrap(),
derive/src/help_parser.rs:121: parse_section("SOME SECTION", input).unwrap(),
derive/src/help_parser.rs:125: parse_section("another section", input).unwrap(),
derive/src/help_parser.rs:146: parse_section("after section", input).unwrap(),
derive/src/lib.rs:76: let mut values = parser.raw_args().unwrap().collect::<Vec<OsString>>();
derive/src/lib.rs:155: let ValueAttr { keys, value } = ValueAttr::parse(&attr).unwrap();However, I'm not sure whether this would result in actually-useful error messages.
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