On Thu Aug 6, 2026 at 11:14 AM BST, Ethan Plant wrote: > The module! macro currently requires a trailing comma after the final > argument, despite using syntax modeled on Rust struct initializers, > where trailing commas are optional. > > Allow parsing to finish after the final field when the input stream is > empty. If more input remains, continue requiring a comma, so missing > separators between fields are still rejected. > > Document that the final trailing comma is optional and update an existing > module! doctest to exercise the syntax without one.
Hmm, I am not sure if we really want this. `module!` invocation usually spans multiple lines so the formatting rules would always prefer adding trailing comma for this case. Allowing omitting sounds like encouraging bad practice. Best, Gary > > Suggested-by: Benno Lossin <[email protected]> > Link: https://github.com/Rust-for-Linux/linux/issues/1172 > Signed-off-by: Ethan Plant <[email protected]> > --- > rust/macros/lib.rs | 4 +++- > rust/macros/module.rs | 7 ++++++- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs > index 4a48fabbc2682..f6474b194687f 100644 > --- a/rust/macros/lib.rs > +++ b/rust/macros/lib.rs > @@ -61,6 +61,8 @@ > /// > /// [`Module`]: ../kernel/trait.Module.html > /// > +/// The trailing comma after the final field is optional. > +/// > /// # Examples > /// > /// ```ignore > @@ -112,7 +114,7 @@ > /// authors: ["Rust for Linux Contributors"], > /// description: "My device driver requires firmware", > /// license: "GPL", > -/// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"], > +/// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"] > /// } > /// > /// struct MyDeviceDriverModule; > diff --git a/rust/macros/module.rs b/rust/macros/module.rs > index 06c18e2075083..57ee79b49a7ec 100644 > --- a/rust/macros/module.rs > +++ b/rust/macros/module.rs > @@ -261,8 +261,13 @@ macro_rules! parse_ordered_fields { > } > } > > - $input.parse::<Token![,]>()?; > seen_keys.push(key); > + > + if $input.is_empty() { > + break; > + } > + > + $input.parse::<Token![,]>()?; > } > > for key in REQUIRED_KEYS { > > --- > base-commit: dc01dfb37b34beeefcfe1c3055364d41a4070c7e > change-id: 20260806-module-optional-trailing-comma-44a336ddf649 > > Best regards, > -- > Ethan Plant <[email protected]>
