[project] Initial commit #1934

joshlf · 2024-10-18T05:45:29Z

TODO: Could we support unsized types so long as we never call offset_of!
on the trailing unsized field?

TODO: Use Name type parameter trick to emit better error messages:
https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=97771667892860935bea60b218f8fdf4

This PR is on branch projection-sized.

[project] Initial commit #1934

We already have the merge queue; running on push is redundant.

Upgrade our MSRV to 1.65 and remove version detection logic prior to that version.

* Release 0.9.0-alpha.0 Upgrade our MSRV to 1.65 and remove version detection logic prior to that version. * Enable clippy::missing_const_for_fn While we're here, remove defensive programming against bug in `Layout::from_size_align` which is no longer needed on our new MSRV.

Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67

Also clean up some code for 0.9.

* Upgrade some code for MSRV 1.65 Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67 * Upgrade versions of some dependencies Now that our MSRV is 1.65, it unlocks upgrading some dependencies' versions.

Bumps [github/codeql-action](https://github.com/github/codeql-action) from 3.26.12 to 3.26.13. - [Release notes](https://github.com/github/codeql-action/releases) - [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md) - [Commits](github/codeql-action@c36620d...f779452) --- updated-dependencies: - dependency-name: github/codeql-action dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [Swatinem/rust-cache](https://github.com/swatinem/rust-cache) from 2.7.3 to 2.7.5. - [Release notes](https://github.com/swatinem/rust-cache/releases) - [Changelog](https://github.com/Swatinem/rust-cache/blob/master/CHANGELOG.md) - [Commits](Swatinem/rust-cache@23bce25...82a92a6) --- updated-dependencies: - dependency-name: Swatinem/rust-cache dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Previously, we supported the `AtLeast` bound, which was used to describe a subset relationship in which `I: AtLeast<J>` implied that `I` as at least as restrictive as `J`. However, as described in #1866, this incorrectly models invariants as monotonic. In reality, invariants both provide guarantees but also *require* guarantees. This commit takes a step in the direction of resolving #1866 by removing `AtLeast`. Uses of `AtLeast<Shared>` are replaced by a new `Reference` trait, which is implemented for `Shared` and `Exclusive`. This serves two purposes: First, it makes it explicit what this bound means. Previously, `AtLeast<Shared>` had an ambiguous meaning, while `Reference` means precisely that an invariant is either `Shared` or `Exclusive` and nothing else. Second, it paves the way for #1183, in which we may add new aliasing invariants which convey ownership. In that case, it will be important for existing methods to add `Reference` bounds when those methods would not be sound in the face of ownership semantics. We also inline the items in the `invariant` module, which were previously generated by macro. The addition of the `Reference` trait did not play nicely with that macro, and we will likely need to go further from the macro in order to fix #1839 – this fix will likely require making aliasing invariants meaningfully different than other invariants, for example by adding an associated type. Makes progress on #1866

Explain why we only support concrete types so that future authors won't spuriously add support for them.

`PtrInner` carries all invariants which are not controlled by type parameters. Since `PtrInner` does not promise to uphold aliasing, alignment, or validity, we can move some utility methods to `PtrInner` which previously were responsible for maintaining invariants orthogonal to their purpose. Makes progress on #1892 (still needs to be fixed on v0.8.x) Closes #1890

This prepares us for future changes which will significantly increase the amount of code in the `invariant` module. Also merge `aliasing_safety` into this new file.

When the aliasing mode is `Any`, `Ptr<'a, T>` is invariant in `'a` and `T`. When the aliasing mode is `Shared` or `Exclusive`, `Ptr` has the same variance as `&'a T` and `&'a mut T` respectively. Makes progress on #1839

Closes #1876

`AliasingSafe` is really about whether a pointer permits unsynchronized reads - either because the referent contains no `UnsafeCell`s or because the aliasing mode is `Exclusive`. Previously, `AliasingSafe` was not named consistent with this meaning, and was a function of a *pair* of types rather than of a single type. This commit fixes both oversights. While we're here, we also add `Read` bounds in some places, allowing us to simplify many safety comments.

For aliasing, use `Inaccessible`. For alignment and validity, use `Unknown`.

This commit adds a framework which supports encoding in the type system any `I -> I` mapping where `I` is any `Invariant` type. This permits us to make `cast_unsized`'s return value smarter, and as a result, allows us to remove a lot of `unsafe` code. Makes progress on #1122

gherrit-pr-id: I003d5360d1b7f7882a71490813eca50b39025f14

These tests depend on `src` being aligned to multiples of 2. With this commit, that dependency is explicitly enforced.

We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509

And allow `non_local_definitions`.

We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509

joshlf · 2024-10-18T05:47:46Z

This supersedes #1933, which has a soundness hole.

This only supports sized types for now, but maybe we'll figure out a way to lift that limitation eventually.

Co-authored-by: Joshua Liebow-Feeser <[email protected]>

Makes progress on #1931 gherrit-pr-id: If0e198c377137dd941ebd5dc68787766a593e1eb

TODO: Could we support unsized types so long as we never call offset_of! on the trailing unsized field? TODO: Use `Name` type parameter trick to emit better error messages: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=97771667892860935bea60b218f8fdf4 gherrit-pr-id: I54eb863c96f056738f58727fc0fec4e1630bf97a

kupiakos · 2024-10-22T17:39:35Z

src/pointer/ptr.rs

+    impl<'a, T, I> Ptr<'a, T, I>
+    where
+        T: 'a + ?Sized,
+        I: Invariants,


Note that this can only ever be sound for invariants that structurally propagate to their fields. This doesn't apply for the Pin invariant.

kupiakos · 2024-10-22T17:41:55Z

src/project.rs

+    // NOTE: Doing the actual cast inside this function makes the `project!`
+    // macro simpler, but it also means that we can't handle both const code and
+    // unsized types at the same time. In order to be const, we can't call trait
+    // methods, but in order to support unsized types, we'd need to provide a


For slice DSTs, all you need is the offset of the last field, which is the same for all sizes. This could be stored as a const.

joshlf and others added 26 commits October 12, 2024 14:06

[ci] Don't run on push (#1882)

5b5d5a6

We already have the merge queue; running on push is redundant.

Release 0.9.0-alpha.0 (#1881)

e7217b5

Upgrade our MSRV to 1.65 and remove version detection logic prior to that version.

Upgrade some code for MSRV 1.65 (#1885)

1788f44

Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67

Clean up some code for new MSRV (#1888)

7349fe0

Also clean up some code for 0.9.

Upgrade versions of some dependencies (#1886)

19ab41c

* Upgrade some code for MSRV 1.65 Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67 * Upgrade versions of some dependencies Now that our MSRV is 1.65, it unlocks upgrading some dependencies' versions.

Roll pinned toolchains on v0.8.x branch (#1887)

5452c3d

[ci] Roll pinned nightly toolchain (#1900)

2e819ac

[ci] Roll pinned nightly toolchain (#1902)

ccf477d

[derive] Document trivial_is_bit_valid (#1905)

967b3a0

Explain why we only support concrete types so that future authors won't spuriously add support for them.

[pointer][invariant] Move to separate file (#1906)

ca9243f

This prepares us for future changes which will significantly increase the amount of code in the `invariant` module. Also merge `aliasing_safety` into this new file.

[pointer] Match variance of references (#1894)

51475bd

When the aliasing mode is `Any`, `Ptr<'a, T>` is invariant in `'a` and `T`. When the aliasing mode is `Shared` or `Exclusive`, `Ptr` has the same variance as `&'a T` and `&'a mut T` respectively. Makes progress on #1839

[pointer] Make invariants opaque, more ergonomic (#1895)

f80a65d

Closes #1876

[pointer] Rename Any -> Unknown/Inaccessible (#1909)

ae43fce

For aliasing, use `Inaccessible`. For alignment and validity, use `Unknown`.

[ci] Roll pinned nightly toolchain (#1915)

77a5f56

Remove items deprecated in 0.8 (#1916)

49749b7

gherrit-pr-id: I003d5360d1b7f7882a71490813eca50b39025f14

Fix flaky TryFromBytes tests (#1917)

f04c344

These tests depend on `src` being aligned to multiples of 2. With this commit, that dependency is explicitly enforced.

Use #[marker] on nightly in CI (#1925)

70e5ef4

We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509

[ci] Roll pinned nightly toolchain (#1928)

d3e44e2

And allow `non_local_definitions`.

Use #[marker] on nightly in CI (#1926)

af67d9a

We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509

joshlf force-pushed the I54eb863c96f056738f58727fc0fec4e1630bf97a branch from 874f368 to 79841ca Compare October 18, 2024 05:55

[ci] Roll pinned stable toolchain (#1938)

5bd167f

joshlf force-pushed the I54eb863c96f056738f58727fc0fec4e1630bf97a branch from 79841ca to b39b4b1 Compare October 18, 2024 13:57

[ci] Roll pinned nightly toolchain (#1935)

706dccf

Co-authored-by: Joshua Liebow-Feeser <[email protected]>

joshlf force-pushed the I54eb863c96f056738f58727fc0fec4e1630bf97a branch 2 times, most recently from 451d820 to 21338e0 Compare October 19, 2024 01:55

google-pr-creation-bot and others added 5 commits October 19, 2024 14:56

[ci] Roll pinned nightly toolchain (#1947)

65e60ae

[ci] Roll pinned nightly toolchain (#1950)

35d9d4f

[ci] Roll pinned nightly toolchain (#1955)

300ddc2

[unsafe-fields] Initial commit (#1929)

986e3c5

Makes progress on #1931 gherrit-pr-id: If0e198c377137dd941ebd5dc68787766a593e1eb

joshlf force-pushed the I54eb863c96f056738f58727fc0fec4e1630bf97a branch from 21338e0 to 5ef235b Compare October 21, 2024 20:03

kupiakos reviewed Oct 22, 2024

View reviewed changes

joshlf force-pushed the main branch from 8ee868d to fe70ab6 Compare February 25, 2025 22:07

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[project] Initial commit #1934

[project] Initial commit #1934

joshlf commented Oct 18, 2024 •

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joshlf commented Oct 18, 2024

kupiakos Oct 22, 2024

kupiakos Oct 22, 2024

[project] Initial commit #1934

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[project] Initial commit #1934

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