Implement ZeroizeOnDrop

CHANGELOG.md

@@ -5,9 +5,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Support `ZeroizeOnDrop`.
+
+### Removed
+- **Breaking Change**: Remove support for `Zeroize(drop)`.
 
 ## [1.0.0-rc.1] - 2021-12-08
 ### Added
 - Initial release.
 
+[Unreleased]: https://github.com/ModProg/derive-where/compare/v1.0.0-rc.1...HEAD
 [1.0.0-rc.1]: https://github.com/ModProg/derive-where/releases/tag/v1.0.0-rc.1

Cargo.toml

@@ -39,6 +39,9 @@ syn = { version = "1", default-features = false, features = [
 [dev-dependencies]
 syn = { version = "1", default-features = false, features = ["extra-traits"] }
 
+[patch.crates-io]
+zeroize = { git = "https://github.com/khonsulabs/utils", branch = "zeroize-on-drop-auto-deref" }
+
 [[test]]
 name = "util"
 path = "tests/util.rs"

README.md

@@ -99,7 +99,7 @@ enum Example<T> {
 
 With a `skip` or `skip_inner` attribute fields can be skipped for traits
 that allow it, which are: [`Debug`], [`Hash`], [`Ord`](https://doc.rust-lang.org/core/cmp/trait.Ord.html), [`PartialOrd`](https://doc.rust-lang.org/core/cmp/trait.PartialOrd.html),
-[`PartialEq`](https://doc.rust-lang.org/core/cmp/trait.PartialEq.html) and [`Zeroize`].
+[`PartialEq`](https://doc.rust-lang.org/core/cmp/trait.PartialEq.html), [`Zeroize`] and [`ZeroizeOnDrop`].
 
 ```rust
 #[derive(DeriveWhere)]
@@ -148,18 +148,16 @@ assert_ne!(
 
 ### `Zeroize` options
 
-[`Zeroize`] has three options:
+[`Zeroize`] has two options:
 - `crate`: an item-level option which specifies a path to the `zeroize`
   crate in case of a re-export or rename.
-- `drop`: an item-level option which implements [`Drop`](https://doc.rust-lang.org/core/ops/trait.Drop.html) and uses
-  [`Zeroize`] to erase all data from memory.
 - `fqs`: a field -level option which will use fully-qualified-syntax instead
   of calling the [`zeroize`][`method@zeroize`] method on `self` directly.
   This is to avoid ambiguity between another method also called `zeroize`.
 
 ```rust
 #[derive(DeriveWhere)]
-#[derive_where(Zeroize(crate = "zeroize_", drop))]
+#[derive_where(Zeroize(crate = "zeroize_"))]
 struct Example(#[derive_where(Zeroize(fqs))] i32);
 
 impl Example {
@@ -181,6 +179,20 @@ Zeroize::zeroize(&mut test);
 assert_eq!(test.0, 0);
 ```
 
+### `ZeroizeOnDrop` options
+
+[`ZeroizeOnDrop`] has one option:
+- `crate`: an item-level option which specifies a path to the `zeroize`
+  crate in case of a re-export or rename.
+
+```
+#[derive(DeriveWhere)]
+#[derive_where(ZeroizeOnDrop(crate = "zeroize_"))]
+struct Example(i32);
+
+assert!(core::mem::needs_drop::<Example>());
+```
+
 ### Supported traits
 
 The following traits can be derived with derive-where:
@@ -194,6 +206,7 @@ The following traits can be derived with derive-where:
 - [`PartialEq`](https://doc.rust-lang.org/core/cmp/trait.PartialEq.html)
 - [`PartialOrd`](https://doc.rust-lang.org/core/cmp/trait.PartialOrd.html)
 - [`Zeroize`]: Only available with the `zeroize` crate feature.
+- [`ZeroizeOnDrop`]: Only available with the `zeroize` crate feature.
 
 ### Supported items
 
@@ -220,7 +233,7 @@ Unions only support [`Clone`](https://doc.rust-lang.org/core/clone/trait.Clone.h
   replaces all cases of [`core::hint::unreachable_unchecked`](https://doc.rust-lang.org/core/hint/fn.unreachable_unchecked.html) in [`Ord`](https://doc.rust-lang.org/core/hint/fn.unreachable_unchecked.html),
   [`PartialEq`](https://doc.rust-lang.org/core/cmp/trait.PartialEq.html) and [`PartialOrd`](https://doc.rust-lang.org/core/cmp/trait.PartialOrd.html), which is what std uses, with
   [`unreachable`](https://doc.rust-lang.org/core/macro.unreachable.html).
-- `zeroize`: Allows deriving [`Zeroize`].
+- `zeroize`: Allows deriving [`Zeroize`] and [`ZeroizeOnDrop`].
 
 ## MSRV
 
@@ -262,5 +275,6 @@ conditions.
 [`Default`]: https://doc.rust-lang.org/core/default/trait.Default.html
 [`Hash`]: https://doc.rust-lang.org/core/hash/trait.Hash.html
 [`Zeroize`]: https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html
+[`ZeroizeOnDrop`]: https://docs.rs/zeroize/latest/zeroize/trait.ZeroizeOnDrop.html
 [`method@zeroize`]: https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html#tymethod.zeroize
 [#27]: https://github.com/ModProg/derive-where/issues/27

ensure-no-std/src/lib.rs

@@ -10,4 +10,4 @@ use derive_where::DeriveWhere;
 #[derive(DeriveWhere)]
 #[derive_where(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
 #[cfg_attr(feature = "zeroize", derive_where(Zeroize))]
-pub struct Test<T>(#[cfg_attr(feature = "zeroize", derive_where(skip(Zeroize)))] PhantomData<T>);
+pub struct Test<T>(PhantomData<T>);

non-msrv-tests/tests/ui/zeroize/item.stderr

@@ -1,34 +1,34 @@
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
  --> tests/ui/zeroize/item.rs:6:16
   |
 6 | #[derive_where(skip_inner, Clone)]
   |                ^^^^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:10:24
    |
 10 | #[derive_where(Debug = invalid; T)]
    |                        ^^^^^^^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:14:16
    |
 14 | #[derive_where(,)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:18:16
    |
 18 | #[derive_where(,Clone)]
    |                ^
 
-error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait syntax, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:22:22
    |
 22 | #[derive_where(Clone,,)]
    |                      ^
 
-error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize
+error: unsupported trait, expected one of expected one of Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd, Zeroize, ZeroizeOnDrop
   --> tests/ui/zeroize/item.rs:26:16
    |
 26 | #[derive_where(T)]

non-msrv-tests/tests/ui/zeroize/zeroize.rs

@@ -24,28 +24,8 @@ struct WrongCrateSyntax<T>(PhantomData<T>);
 #[derive_where(Zeroize(crate = "struct Test"))]
 struct InvalidCrate<T>(PhantomData<T>);
 
-#[derive(DeriveWhere)]
-#[derive_where(Zeroize(drop, drop))]
-struct DuplicateDrop<T>(PhantomData<T>);
-
 #[derive(DeriveWhere)]
 #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_"))]
 struct DuplicateCrate<T>(PhantomData<T>);
 
-#[derive(DeriveWhere)]
-#[derive_where(Zeroize(drop, drop, crate = "zeroize_"))]
-struct DuplicateDropWithCrate<T>(PhantomData<T>);
-
-#[derive(DeriveWhere)]
-#[derive_where(Zeroize(drop, crate = "zeroize_", crate = "zeroize_"))]
-struct DropWithDuplicateCrate<T>(PhantomData<T>);
-
-#[derive(DeriveWhere)]
-#[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_", drop))]
-struct DuplicateCrateWithDrop<T>(PhantomData<T>);
-
-#[derive(DeriveWhere)]
-#[derive_where(Zeroize(crate = "zeroize_", drop, drop))]
-struct CrateWithDuplicateDrop<T>(PhantomData<T>);
-
 fn main() {}

non-msrv-tests/tests/ui/zeroize/zeroize.stderr

@@ -28,38 +28,8 @@ error: expected path, expected identifier
 24 | #[derive_where(Zeroize(crate = "struct Test"))]
    |                                ^^^^^^^^^^^^^
 
-error: duplicate `drop` option
-  --> tests/ui/zeroize/zeroize.rs:28:30
-   |
-28 | #[derive_where(Zeroize(drop, drop))]
-   |                              ^^^^
-
 error: duplicate `crate` option
-  --> tests/ui/zeroize/zeroize.rs:32:44
+  --> tests/ui/zeroize/zeroize.rs:28:44
    |
-32 | #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_"))]
+28 | #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_"))]
    |                                            ^^^^^^^^^^^^^^^^^^
-
-error: duplicate `drop` option
-  --> tests/ui/zeroize/zeroize.rs:36:30
-   |
-36 | #[derive_where(Zeroize(drop, drop, crate = "zeroize_"))]
-   |                              ^^^^
-
-error: duplicate `crate` option
-  --> tests/ui/zeroize/zeroize.rs:40:50
-   |
-40 | #[derive_where(Zeroize(drop, crate = "zeroize_", crate = "zeroize_"))]
-   |                                                  ^^^^^^^^^^^^^^^^^^
-
-error: duplicate `crate` option
-  --> tests/ui/zeroize/zeroize.rs:44:44
-   |
-44 | #[derive_where(Zeroize(crate = "zeroize_", crate = "zeroize_", drop))]
-   |                                            ^^^^^^^^^^^^^^^^^^
-
-error: duplicate `drop` option
-  --> tests/ui/zeroize/zeroize.rs:48:50
-   |
-48 | #[derive_where(Zeroize(crate = "zeroize_", drop, drop))]
-   |                                                  ^^^^

non-msrv-tests/tests/util.rs

@@ -6,7 +6,7 @@ use std::{
 };
 
 #[cfg(feature = "zeroize")]
-use zeroize_::Zeroize;
+use zeroize_::{Zeroize, ZeroizeOnDrop};
 
 pub struct Wrapper<T = ()> {
 	data: i32,
@@ -44,6 +44,9 @@ impl<T> Zeroize for Wrapper<T> {
 #[cfg(feature = "zeroize")]
 pub struct AssertZeroize<'a, T: Zeroize>(pub &'a T);
 
+#[cfg(feature = "zeroize")]
+pub struct AssertZeroizeOnDrop<'a, T: ZeroizeOnDrop>(pub &'a T);
+
 pub fn test_drop<T>(value: T, fun: impl FnOnce(&T)) {
 	let mut test_holder = vec![value];
 	let ptr = &mut test_holder[0] as *mut T;

non-msrv-tests/tests/zeroize.rs

@@ -12,7 +12,7 @@ use std::{
 use derive_where::DeriveWhere;
 use zeroize::Zeroize;
 
-use self::util::{AssertZeroize, Wrapper};
+use self::util::{AssertZeroize, AssertZeroizeOnDrop, Wrapper};
 
 #[test]
 fn basic() {
@@ -51,12 +51,13 @@ fn crate_() {
 #[test]
 fn drop() {
 	#[derive(DeriveWhere)]
-	#[derive_where(Zeroize(drop))]
+	#[derive_where(Zeroize, ZeroizeOnDrop)]
 	struct Test<T>(Wrapper<T>);
 
 	let mut test = Test(42.into());
 
 	let _ = AssertZeroize(&test);
+	let _ = AssertZeroizeOnDrop(&test);
 
 	test.zeroize();
 
@@ -83,12 +84,13 @@ fn fqs() {
 	}
 
 	#[derive(DeriveWhere)]
-	#[derive_where(Zeroize(drop))]
+	#[derive_where(Zeroize, ZeroizeOnDrop)]
 	struct Test<T>(#[derive_where(Zeroize(fqs))] Fqs<T>);
 
 	let mut test = Test(Fqs(42.into()));
 
 	let _ = AssertZeroize(&test);
+	let _ = AssertZeroizeOnDrop(&test);
 
 	test.zeroize();
 
@@ -116,12 +118,13 @@ fn deref() {
 	}
 
 	#[derive(DeriveWhere)]
-	#[derive_where(Zeroize(drop))]
+	#[derive_where(Zeroize, ZeroizeOnDrop)]
 	struct Test<T>(ZeroizeDeref<T>);
 
 	let mut test = Test::<()>(ZeroizeDeref(42, PhantomData));
 
 	let _ = AssertZeroize(&test);
+	let _ = AssertZeroizeOnDrop(&test);
 
 	test.zeroize();
 

src/attr/item.rs

@@ -309,8 +309,12 @@ pub enum DeriveTrait {
 	Zeroize {
 		/// [`Zeroize`](https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html) path.
 		crate_: Option<Path>,
-		/// [`Zeroize`](https://docs.rs/zeroize/latest/zeroize/trait.Zeroize.html) [`Drop`] implementation.
-		drop: bool,
+	},
+	/// [`ZeroizeOnDrop`](https://docs.rs/zeroize/latest/zeroize/trait.ZeroizeOnDrop.html).
+	#[cfg(feature = "zeroize")]
+	ZeroizeOnDrop {
+		/// [`ZeroizeOnDrop`](https://docs.rs/zeroize/latest/zeroize/trait.ZeroizeOnDrop.html) path.
+		crate_: Option<Path>,
 	},
 }
 
@@ -340,6 +344,8 @@ impl Deref for DeriveTrait {
 			PartialOrd => &Trait::PartialOrd,
 			#[cfg(feature = "zeroize")]
 			Zeroize { .. } => &Trait::Zeroize,
+			#[cfg(feature = "zeroize")]
+			ZeroizeOnDrop { .. } => &Trait::ZeroizeOnDrop,
 		}
 	}
 }
@@ -421,6 +427,16 @@ impl DeriveTrait {
 					util::path_from_strs(&["zeroize", "Zeroize"])
 				}
 			}
+			#[cfg(feature = "zeroize")]
+			ZeroizeOnDrop { crate_, .. } => {
+				if let Some(crate_) = crate_ {
+					let mut crate_ = crate_.clone();
+					crate_.segments.push(util::path_segment("ZeroizeOnDrop"));
+					crate_
+				} else {
+					util::path_from_strs(&["zeroize", "ZeroizeOnDrop"])
+				}
+			}
 		}
 	}
 

src/error.rs

@@ -225,6 +225,8 @@ impl Error {
 			"PartialOrd",
 			#[cfg(feature = "zeroize")]
 			"Zeroize",
+			#[cfg(feature = "zeroize")]
+			"ZeroizeOnDrop",
 		]
 		.join(", ")
 	}

src/input.rs

@@ -144,10 +144,11 @@ impl<'a> Input<'a> {
 				#[cfg(feature = "zeroize")]
 				{
 					// `Zeroize(crate = "..")` is used.
-					if let DeriveTrait::Zeroize {
-						crate_: Some(_), ..
-					} = **trait_
-					{
+					if let DeriveTrait::Zeroize { crate_: Some(_) } = **trait_ {
+						continue;
+					}
+					// `ZeroizeOnDrop(crate = "..")` is used.
+					if let DeriveTrait::ZeroizeOnDrop { crate_: Some(_) } = **trait_ {
 						continue;
 					}
 					// `Zeroize(fqs)` is used on any field.