From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B2884335098; Wed, 14 Jan 2026 18:20:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768414852; cv=none; b=piYR4VmaDtHvTHqh70iIP694GZ/ymZ9NKBi5Cy1OmztQ/af+TOxigaCljOU8/bz2wuavPPPsywtzXwip1mIg6FuBz8avhJVW6N1C3pBvE+RloUJGNDSfM/PQNlXwTb2GzUlnZHZBv++uha1aaqZMnFeH/qgNqo7zEHjD15SZrF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768414852; c=relaxed/simple; bh=gO/f+n6bxctI9TpFgKPzkstQvLvIbWAHwyepVBKbGrw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VWmJGD3f/9W6Tz6zzh1/Oj2W4nuq2d8nQv6MBIkKAQ7ysd38nQJj3u6ctShxcZfWra+K7hX6HiCEaSnheTNGgmla5/vciFfkKKrueB/QmRl9vh34i4YZb9QlfH/QKQtpV4JPVm93PxqbRNkyhO0iutijLnti3M74wErZexbrqHg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cnt6SXs+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cnt6SXs+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2749EC4CEF7; Wed, 14 Jan 2026 18:20:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768414852; bh=gO/f+n6bxctI9TpFgKPzkstQvLvIbWAHwyepVBKbGrw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cnt6SXs+ASo3isiv7C6/sC3459tn9OJBXrYXeqOCZQZL6XbYTY5m+v0ptn8eU4Elh aAT67XAEPOcORvprkATtOcH4VS2UDk8MtuMjylpbk83127xBqIBGbQ5OA/5+K852zR 8dvDVWRFhIS++5MO1t9uDVMXQm+i+LfXc+MkxFRXV7R3EzxGFpXUIVH04n5yf/fGOV H+edjRwMs1t7KFV4hnSb2R1Vpdv4HGTVw6diWQopEC5UyCivivoGRMcZ2rHFdL6SAQ JHIneVj4zsazpRzfRM6ld7ohkzLebrsf+LXul4OmDsLl8l4laSzRJpx1/iwdFNJP+G H4WG33D9j5JUA== From: Benno Lossin To: Benno Lossin , Gary Guo , Miguel Ojeda , Boqun Feng , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 10/15] rust: pin-init: add `#[default_error()]` attribute to initializer macros Date: Wed, 14 Jan 2026 19:18:45 +0100 Message-ID: <20260114181934.1782470-11-lossin@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260114181934.1782470-1-lossin@kernel.org> References: <20260114181934.1782470-1-lossin@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The `#[default_error()]` attribute can be used to supply a default type as the error used for the `[pin_]init!` macros. This way one can easily define custom `try_[pin_]init!` variants that default to your project specific error type. Just write the following declarative macro: macro_rules! try_init { ($($args:tt)*) => { ::pin_init::init!( #[default_error(YourCustomErrorType)] $($args)* ) } } Tested-by: Andreas Hindborg Signed-off-by: Benno Lossin --- Changes in v3: none Changes in v2: * improve error handling * improve parsing and default error evaluation --- rust/pin-init/internal/src/init.rs | 42 ++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-) diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs index b0eb66224341..5a66016bdf33 100644 --- a/rust/pin-init/internal/src/init.rs +++ b/rust/pin-init/internal/src/init.rs @@ -8,12 +8,13 @@ parse_quote, punctuated::Punctuated, spanned::Spanned, - token, Block, Expr, ExprCall, ExprPath, Ident, Path, Token, Type, + token, Attribute, Block, Expr, ExprCall, ExprPath, Ident, Path, Token, Type, }; use crate::diagnostics::{DiagCtxt, ErrorGuaranteed}; pub(crate) struct Initializer { + attrs: Vec, this: Option, path: Path, brace_token: token::Brace, @@ -54,8 +55,17 @@ fn ident(&self) -> Option<&Ident> { } } +enum InitializerAttribute { + DefaultError(DefaultErrorAttribute), +} + +struct DefaultErrorAttribute { + ty: Type, +} + pub(crate) fn expand( Initializer { + attrs, this, path, brace_token, @@ -69,7 +79,16 @@ pub(crate) fn expand( ) -> Result { let error = error.map_or_else( || { - if let Some(default_error) = default_error { + if let Some(default_error) = attrs.iter().fold(None, |acc, attr| { + #[expect(irrefutable_let_patterns)] + if let InitializerAttribute::DefaultError(DefaultErrorAttribute { ty }) = attr { + Some(ty.clone()) + } else { + acc + } + }) { + default_error + } else if let Some(default_error) = default_error { syn::parse_str(default_error).unwrap() } else { dcx.error(brace_token.span.close(), "expected `? ` after `}`"); @@ -358,6 +377,7 @@ fn make_field_check( impl Parse for Initializer { fn parse(input: syn::parse::ParseStream<'_>) -> syn::Result { + let attrs = input.call(Attribute::parse_outer)?; let this = input.peek(Token![&]).then(|| input.parse()).transpose()?; let path = input.parse()?; let content; @@ -389,7 +409,19 @@ fn parse(input: syn::parse::ParseStream<'_>) -> syn::Result { .peek(Token![?]) .then(|| Ok::<_, syn::Error>((input.parse()?, input.parse()?))) .transpose()?; + let attrs = attrs + .into_iter() + .map(|a| { + if a.path().is_ident("default_error") { + a.parse_args::() + .map(InitializerAttribute::DefaultError) + } else { + Err(syn::Error::new_spanned(a, "unknown initializer attribute")) + } + }) + .collect::, _>>()?; Ok(Self { + attrs, this, path, brace_token, @@ -400,6 +432,12 @@ fn parse(input: syn::parse::ParseStream<'_>) -> syn::Result { } } +impl Parse for DefaultErrorAttribute { + fn parse(input: syn::parse::ParseStream<'_>) -> syn::Result { + Ok(Self { ty: input.parse()? }) + } +} + impl Parse for This { fn parse(input: syn::parse::ParseStream<'_>) -> syn::Result { Ok(Self { -- 2.52.0