This Writer is a simple wrapper around `Vec<u8>` that makes sure
that its contents are cleared whenever they are dropped _or
reallocated_.
The reallocation is the important part here: without that, we risk
not zeroizing the first allocation of the buffer.
Do _not_ bump the dependency versions on crates that have had no
changes since arti 0.0.5, since those crates do not depend on the
new APIs.
```
cargo set-version -p tor-basic-utils --bump patch
cargo set-version -p tor-llcrypto --bump patch
git restore crates/tor-checkable
git restore crates/tor-consdiff
git restore crates/tor-rtmock
```
This comprises four renames:
```
write_onto -> write_onto_infallible
write_into -> write_into_infallible
write -> write_infallible
writer_and_consume -> write_and_consume_infallible.
```
The rest of this branch will be concerned with replacing these
`_infallible` methods with ones that return a `Result`. This is
part of #513.
Since there is currently only one error type that can occur when
encoding, it doesn't make sense to use the full Error type here.
This split will help us downstream, as we no longer need to
categorize tor_bytes::Error as "an error in encoding or decoding".
I considered renaming Error to DecodeError, but that had pretty huge
downstream effects, and didn't seem to be worth it.
This commit was made by reverting the previous commit, then
re-running the script I used to generate it. In theory there should
be no semantic changes: only changes due to improved formatting from
cargo edit.
I followed the following procedure to make these changes:
* I used maint/changed_crates to find out which crates had changed
since 0.3.0.
* I used grep and maint/list_crates to sort those crates in
topological (dependency) order.
* I looked through semver_status to find which crates were listed as
having semver-relevant changes (new APIs and breaking changes).
* I scanned through the git logs of the crates with no
semver-relevant changes listed to confirm that, indeed, they had
no changes. For those crates, I incremented their patch-level
version _without_ changing the version that other crates depend on.
* I scanned through the git logs of the crates with no
semver-relevant changes listed to confirm that, indeed, they had
no obvious breaking changes.
* I treated all crates that depend on `arti` and/or `arti-client` as
having breaking changes.
* I identified crates that depend on crates that have changed, even
if they have not changed themselves, and identified them as having
a non-breaking change.
* For all of the crates, I used `cargo set-version -p $CRATE --bump
$STATUS` (where `STATUS` is `patch` or `minor`) to update the
versions, and the depended-upon versions.
These crates had only clippy fixes that do not affect their
behavior:
tor-bytes
tor-cell
tor-events
tor-linkspec
tor-netdir
tor-socksproto
This crate only had the cargo-husky dependency removed, which
does not affect compatibility:
tor-llcrypto
Since these changes have no compatibility effects, it is not
necessary to bump the versions of these crates which other crates
depend on.
This is an automated change made with a perl one-liner and verified
with grep -L and grep -l.
Some warnings are introduced with this change; they will be removed
in subsequent commits.
See arti#208 for older discussion on this issue.
Not all of these strictly need to be bumped to 0.2.0; many could go
to 0.1.1 instead. But since everything at the tor-rtcompat and
higher layers has had breaking API changes, it seems not so useful
to distinguish. (It seems unlikely that anybody at this stage is
depending on e.g. tor-protover but not arti-client.)
This lint is IMO inherently ill-conceived.
I have looked for the reasons why this might be thought to be a good
idea and there were basically two (and they are sort of contradictory):
I. "Calling ‘.clone()` on an Rc, Arc, or Weak can obscure the fact
that only the pointer is being cloned, not the underlying data."
This is the wording from
https://rust-lang.github.io/rust-clippy/v0.0.212/#clone_on_ref_ptr
It is a bit terse; we are left to infer why it is a bad idea to
obscure this fact. It seems to me that if it is bad to obscure some
fact, that must be because the fact is a hazard. But why would it be
a hazard to not copy the underlying data ?
In other languages, faliing to copy the underlying data is a serious
correctness hazard. There is a whose class of bugs where things were
not copied, and then mutated and/or reused in multiple places in ways
that were not what the programmer intended. In my experience, this is
a very common bug when writing Python and Javascript. I'm told it's
common in golang too.
But in Rust this bug is much much harder to write. The data inside an
Arc is immutable. To have this bug you'd have use interior mutability
- ie mess around with Mutex or RefCell. That provides a good barrier
to these kind of accidents.
II. "The reason for writing Rc::clone and Arc::clone [is] to make it
clear that only the pointer is being cloned, as opposed to the
underlying data. The former is always fast, while the latter can
be very expensive depending on what is being cloned."
This is the reasoning found here
https://github.com/rust-lang/rust-clippy/issues/2048
This is saying that *not* using Arc::clone is hazardous.
Specifically, that a deep clone is a performance hazard.
But for this argument, the lint is precisely backwards. It's linting
the "good" case and asking for it to be written in a more explicit
way; while the supposedly bad case can be written conveniently.
Also, many objects (in our codebase, and in all the libraries we use)
that are Clone are in fact simply handles. They contain Arc(s) (or
similar) and are cheap to clone. Indeed, that is the usual case.
It does not make sense to distinguish in the syntax we use to clone
such a handle, whether the handle is a transparent Arc, or an opaque
struct containing one or more other handles.
Forcing Arc::clone to be written as such makes for code churn when a
type is changed from Arc<Something> to Something: Clone, or vice
versa.
I found these versions empirically, by using the following process:
First, I used `cargo tree --depth 1 --kind all` to get a list of
every immediate dependency we had.
Then, I used `cargo upgrade --workspace package@version` to change
each dependency to the earliest version with which (in theory) the
current version is semver-compatible. IOW, if the current version
was 3.2.3, I picked "3". If the current version was 0.12.8, I
picked "0.12".
Then, I used `cargo +nightly upgrade -Z minimal-versions` to
downgrade Cargo.lock to the minimal listed version for each
dependency. (I had to override a few packages; see .gitlab-ci.yml
for details).
Finally, I repeatedly increased the version of each of our
dependencies until our code compiled and the tests passed. Here's
what I found that we need:
anyhow >= 1.0.5: Earlier versions break our hyper example.
async-broadcast >= 0.3.2: Earlier versions fail our tests.
async-compression 0.3.5: Earlier versions handled futures and tokio
differently.
async-trait >= 0.1.2: Earlier versions are too buggy to compile our
code.
clap 2.33.0: For Arg::default_value_os().
coarsetime >= 0.1.20: exposed as_ticks() function.
curve25519-dalek >= 3.2: For is_identity().
generic-array 0.14.3: Earlier versions don't implement
From<&[T; 32]>
httparse >= 1.2: Earlier versions didn't implement Error.
itertools at 0.10.1: For at_most_once.
rusqlite >= 0.26.3: for backward compatibility with older rustc.
serde 1.0.103: Older versions break our code.
serde_json >= 1.0.50: Since we need its Value type to implement Eq.
shellexpand >= 2.1: To avoid a broken dirs crate version.
tokio >= 1.4: For Handle::block_on().
tracing >= 0.1.18: Previously, tracing_core and tracing had separate
LevelFilter types.
typenum >= 1.12: Compatibility with rust-crypto crates
x25519-dalek >= 1.2.0: For was_contributory().
Closes#275.
We want to only use TODO in the codebase for non-blockers, and open
tickets for anything that is a bigger blocker than a TODO. These
XXXXs seem like definite non-blockers to me.
Part of arti#231.
Now that we have const generics, we can use them. We can also avoid
an extra clone in the implementation for [u8; N].
Nothing in our codebase requires that we use Reader or Writer on a
GenericArray holding anything other than u8, so I've switched back
to the more efficient implementation there.
I've added a fuzzer case for the new method, but apparently rustc nightly isn't working too
well with fuzzers for me; I'm going to try it tomorrow.
trinity-1686a
Nick Mathewson
eta
Ian Jackson
Ian Jackson
Orhun Parmaksız
Samanta Navarro
Daniel Eades
Jani Monoses