Allow user to set the crate path of num_enum #77

yshui · 2022-09-12T22:56:39Z

Add a #[num_enum(crate = ..)] attribute, which lets the user set where the num_enum crate is located.

yshui · 2022-09-13T09:59:47Z

This closes #76

danielhenrymantilla

Great, thanks for the quick PR! 🙏

I have some nits here and there, but otherwise LGTM ✅

danielhenrymantilla · 2022-09-13T10:46:41Z

num_enum/tests/try_from_primitive.rs

+mod reexport {
+    pub use ::num_enum;
+}


Could you have this on its own tests/file.rs, and then, use, instead:

Suggested change

mod reexport {

pub use ::num_enum;

}

extern crate std as num_enum; // ensure `::num_enum` is a bad path

mod reexport {

pub extern crate num_enum;

}

This way if the macro decided to ignore the crate parameter, we will detect it and fail 🙂

danielhenrymantilla · 2022-09-13T10:49:41Z

num_enum_derive/src/lib.rs

+        let s: syn::LitStr = input.parse()?;
+        let path = s.parse_with(syn::Path::parse_mod_style)?;


Suggested change

let s: syn::LitStr = input.parse()?;

let path = s.parse_with(syn::Path::parse_mod_style)?;

let path = syn::Path::parse_mod_style(input)?;

The fact serde uses a literal on the rhs of crate = … is a historical artifact (crate = ::some_path was not legal at the beginning), but nowadays not requiring code to be stringified is better for spans and IDEs 🙂

danielhenrymantilla · 2022-09-13T11:01:18Z

num_enum_derive/src/lib.rs

+            for attr in attrs {
+                if attr.path.is_ident("num_enum") {
+                    match attr.parse_args_with(NumEnumAttributes::parse) {
+                        Ok(NumEnumAttributes { items }) => {
+                            if items.len() != 1 || crate_path.is_some() {
+                                die!(attr.tokens => "Expected exactly one `crate` argument");
+                            } else {
+                                let NumEnumAttributeItem::Crate(item) =
+                                    items.into_iter().next().unwrap();
+                                crate_path = Some(item.path);
+                            }
+                        }
+                        Err(err) => {
+                            die!(attr =>
+                                format!("Invalid attribute: {}", err)
+                            );
+                        }
+                    }


This won't "scale well" if other attributes are added. I'd rather suggest an approach along the lines of .flat_map()ing / nested-for-style the attributes (since #[num_enum(foo)] #[num_enum(bar)] is the same as #[num_enum(foo, bar)]:

for attr in attrs { if attr.path.is_ident("num_enum") { for item in attr.parse_args_with(NumEnumAttributes::parse)? { match item { // when written like this, it's easier to extend with more attrs. NumEnumAttributeItem::Crate(item) => { if crate_path.is_some() { die!(item.path => "duplicate `crate` annotation"); } crate_path = Some(item.path); }, } } } … }

danielhenrymantilla · 2022-09-13T11:02:56Z

num_enum_derive/src/lib.rs

+        syn::LitStr::new(&format!("::{}", get_crate_name()), Span::call_site())
+            .parse_with(syn::Path::parse_mod_style)
+            .unwrap()


Suggested change

syn::LitStr::new(&format!("::{}", get_crate_name()), Span::call_site())

.parse_with(syn::Path::parse_mod_style)

.unwrap()

let krate = get_crate_name();

parse_quote!( :: #krate )

this parse_quote! would generate :: "num_enum" because krate is a String

maybe let krate = format_ident!("{}", get_crate_name());?

Ah true, yeah what you've just suggested would be the right thing.

Although at that point, I guess we could go back to something closer to your original suggestion:

syn::parse_str(&format!("::{}", get_crate_name())).unwrap()

(it just sidesteps the intermediary LitStr)

danielhenrymantilla · 2022-09-13T11:04:03Z

num_enum_derive/src/lib.rs

+    let krate = enum_info.crate_path.clone().unwrap_or_else(|| {
+        syn::LitStr::new(&format!("::{}", get_crate_name()), Span::call_site())
+            .parse_with(syn::Path::parse_mod_style)
+            .unwrap()
+    });


Hmm, given the code duplication, I wonder if get_crate_name() shouldn't be taking a Option<Path> parameter and being the one emitting the actual path?

Add a `#[num_enum(crate = ..)]` attribute, which lets the user set where the num_enum crate is located.

yshui · 2023-01-11T16:35:58Z

@danielhenrymantilla hey, sorry for taking a while to get back to this. i think i have now addressed most of the points.

danielhenrymantilla

Great!

illicitonion

LGTM, thanks! I have suggestions for a few very small tweaks, then let's merge!

illicitonion · 2023-01-15T00:15:04Z

num_enum/tests/try_build/compile_fail/multiple_crate_path.stderr

@@ -0,0 +1,5 @@
+error: Expected exactly one `crate` argument


I'd expect this error message to be "at most one" rather than "exactly one" - it's allowed to not specify a crate argument.

illicitonion · 2023-01-15T00:15:19Z

num_enum/tests/try_build/compile_fail/variants_with_fields.stderr

@@ -1,16 +1,16 @@
-error: `num_enum` only supports unit variants (with no associated data), but `Number::NonZero` was not a unit variant.
+error: `:: num_enum` only supports unit variants (with no associated data), but `Number::NonZero` was not a unit variant.


I wouldn't expect a space between :: and num_enum here?

illicitonion · 2023-01-15T00:47:53Z

num_enum_derive/src/lib.rs

+                        match item {
+                            NumEnumAttributeItem::Crate(item) => {
+                                if crate_path.is_some() {
+                                    die!(attr.tokens => "Expected exactly one `crate` argument");


Suggested change

die!(attr.tokens => "Expected exactly one `crate` argument");

die!(attr.tokens => "Expected at most one `crate` argument");

illicitonion · 2023-01-15T00:51:22Z

num_enum_derive/src/lib.rs

+            proc_macro_crate::FoundCrate::Itself => parse_quote!(::num_enum),
+            proc_macro_crate::FoundCrate::Name(name) => {
+                let krate = format_ident!("{}", name);
+                parse_quote!( :: #krate )


Suggested change

parse_quote!( :: #krate )

parse_quote!( ::#krate )

illicitonion · 2023-01-15T00:55:23Z

num_enum_derive/src/lib.rs

 // Don't depend on proc-macro-crate in no_std environments because it causes an awkward dependency
 // on serde with std.
 //
 // no_std dependees on num_enum cannot rename the num_enum crate when they depend on it. Sorry.
 //
 // See https://github.com/illicitonion/num_enum/issues/18
 #[cfg(not(feature = "proc-macro-crate"))]
-fn get_crate_name() -> String {
-    String::from("num_enum")
+fn get_crate_name(path: Option<syn::Path>) -> syn::Path {


Suggested change

fn get_crate_name(path: Option<syn::Path>) -> syn::Path {

fn get_crate_path(path: Option<syn::Path>) -> syn::Path {

Let's rename this (and the other #[cfg-gated one, and its call sites) to make more clear that it has the :: prefix (and that callers don't need to add it)

diondokter · 2023-12-13T15:13:54Z

Can I help in any way to get this over the finish line and get this feature released?

danielhenrymantilla reviewed Sep 13, 2022

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Allow user to set the crate path of num_enum

51ef39c

Add a `#[num_enum(crate = ..)]` attribute, which lets the user set where the num_enum crate is located.

yshui force-pushed the main branch from 35eea84 to 51ef39c Compare January 11, 2023 16:35

danielhenrymantilla approved these changes Jan 12, 2023

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illicitonion reviewed Jan 15, 2023

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Allow user to set the crate path of num_enum #77

Allow user to set the crate path of num_enum #77

yshui commented Sep 12, 2022

yshui commented Sep 13, 2022

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danielhenrymantilla Sep 13, 2022

danielhenrymantilla Sep 13, 2022

danielhenrymantilla Sep 13, 2022 •

edited

danielhenrymantilla Sep 13, 2022

yshui Jan 11, 2023

yshui Jan 11, 2023

danielhenrymantilla Jan 12, 2023

danielhenrymantilla Sep 13, 2022 •

edited

yshui commented Jan 11, 2023

danielhenrymantilla left a comment

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illicitonion Jan 15, 2023

illicitonion Jan 15, 2023

illicitonion Jan 15, 2023

illicitonion Jan 15, 2023

illicitonion Jan 15, 2023

diondokter commented Dec 13, 2023

		let s: syn::LitStr = input.parse()?;
		let path = s.parse_with(syn::Path::parse_mod_style)?;

	let s: syn::LitStr = input.parse()?;
	let path = s.parse_with(syn::Path::parse_mod_style)?;
	let path = syn::Path::parse_mod_style(input)?;

		@@ -1,16 +1,16 @@
		error: `num_enum` only supports unit variants (with no associated data), but `Number::NonZero` was not a unit variant.
		error: `:: num_enum` only supports unit variants (with no associated data), but `Number::NonZero` was not a unit variant.

	die!(attr.tokens => "Expected exactly one `crate` argument");
	die!(attr.tokens => "Expected at most one `crate` argument");

	fn get_crate_name(path: Option<syn::Path>) -> syn::Path {
	fn get_crate_path(path: Option<syn::Path>) -> syn::Path {

Allow user to set the crate path of num_enum #77

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Allow user to set the crate path of num_enum #77

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diondokter commented Dec 13, 2023

danielhenrymantilla Sep 13, 2022 •

edited

danielhenrymantilla Sep 13, 2022 •

edited