7793: implement io-uring for read_to_string.rs#40
7793: implement io-uring for read_to_string.rs#40martin-augment wants to merge 1 commit intomasterfrom
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WalkthroughThe change modifies the ✨ Finishing touches
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Pull Request Review: Implement io-uring for read_to_string.rsI've reviewed PR #40 and have the following feedback: ✅ Positives
🔍 Issues and Concerns1. Critical Bug: Error discarding UTF-8 error details (tokio/src/fs/read_to_string.rs:44)String::from_utf8(vec).map_err(|_| {
io::Error::new(
io::ErrorKind::InvalidData,
"stream did not contain valid UTF-8",
)
})Problem: The original Recommendation: Preserve the error details: String::from_utf8(vec).map_err(|e| {
io::Error::new(
io::ErrorKind::InvalidData,
e.utf8_error(),
)
})This matches the pattern in tokio-util/src/codec/mod.rs:203-208 and provides better debugging information. 2. Ownership/Lifetime Issue (tokio/src/fs/read_to_string.rs:28, 54)The current implementation has a subtle lifetime inconsistency:
Concern: While this works, it's slightly inefficient because:
Recommendation: Consider cloning once at the start for consistency with the original implementation and pub async fn read_to_string(path: impl AsRef<Path>) -> io::Result<String> {
let path = path.as_ref().to_owned(); // Clone once upfront
#[cfg(all(...))]
{
use crate::fs::read_uring;
let handle = crate::runtime::Handle::current();
let driver_handle = handle.inner.driver().io();
if driver_handle.check_and_init()? {
return read_uring(&path).await.and_then(|vec| {
String::from_utf8(vec).map_err(|e| {
io::Error::new(io::ErrorKind::InvalidData, e.utf8_error())
})
});
}
}
asyncify(move || std::fs::read_to_string(path)).await
}This eliminates the helper function and matches Alternative: If you prefer the current borrowed approach for micro-optimization, document why this differs from 3. Documentation needs update (tokio/src/fs/read_to_string.rs:11)The documentation states:
This is now inaccurate when io-uring is enabled. Recommendation: Add an io-uring section similar to /// # io_uring support
///
/// On Linux, you can also use io_uring for executing system calls. To enable
/// io_uring, you need to specify the `--cfg tokio_unstable` flag at compile time,
/// enable the io-uring cargo feature, and set the `Builder::enable_io_uring`
/// runtime option.
///
/// Support for io_uring is currently experimental, so its behavior may change
/// or it may be removed in future versions.
📊 Test CoverageMissing: No specific tests for the io-uring path in Observation: The existing tests in tokio/tests/io_read_to_string.rs test the Recommendation:
🎯 Performance ConsiderationsThe io-uring implementation should provide better performance for:
No concerns with the implementation itself. 🔒 SecurityNo security issues identified. The UTF-8 validation properly prevents invalid data from being returned as a String. SummaryThis is a solid implementation that correctly adds io-uring support to
Great work on maintaining consistency with the existing 🤖 Generated with Claude Code |
🤖 Augment PR SummarySummary: Adds an io-uring fast path for Changes:
Technical Notes: The io-uring path is gated behind 🤖 Was this summary useful? React with 👍 or 👎 |
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| let path = path.as_ref().to_owned(); | ||
| let path = path.as_ref(); | ||
|
|
||
| #[cfg(all( |
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The doc comment above says this always runs the blocking operation via spawn_blocking, but with this new io-uring fast path that’s no longer always true; consider updating the docs to reflect the conditional behavior.
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value:good-to-have; category:documentation; feedback:The Augment AI reviewer is correct! The documentation needs to be updated that if Linux IO_Uring is enabled then no new thread will be spawned. Prevents releasing an obsolete rustdoc for the read_to_string function.
| let driver_handle = handle.inner.driver().io(); | ||
| if driver_handle.check_and_init()? { | ||
| return read_uring(path).await.and_then(|vec| { | ||
| String::from_utf8(vec).map_err(|_| { |
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map_err(|_| ...) discards the FromUtf8Error, which makes this error less informative than the std::fs::read_to_string fallback (and may change error chaining). Consider preserving the underlying UTF-8 error as the IO error source.
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value:useful; category:bug; feedback:The Augment AI reviewer is correct! The original error is ignored and a new error message is used. Utf8Error's Display impl is better because it knows when the bytes contain invalid data or incomplete utf8 sequence. Also using "stream" here is not correct because there is no streaming at all. Prevents returning a misleading error message in case of a utf8 related problem.
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Actionable comments posted: 1
🧹 Nitpick comments (1)
tokio/src/fs/read_to_string.rs (1)
10-11: Documentation now inaccurate with io-uring path.The docstring states the operation is "implemented by running the equivalent blocking operation on a separate thread pool using
spawn_blocking", but with the io-uring path enabled, this is no longer always true.🔎 Suggested documentation update
-/// This operation is implemented by running the equivalent blocking operation -/// on a separate thread pool using [`spawn_blocking`]. +/// By default, this operation is implemented by running the equivalent blocking +/// operation on a separate thread pool using [`spawn_blocking`]. When the +/// `io-uring` feature is enabled on Linux, this may use io-uring instead.
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📒 Files selected for processing (1)
tokio/src/fs/read_to_string.rs
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🧠 Learnings (1)
📓 Common learnings
Learnt from: martin-augment
Repo: martin-augment/tokio PR: 10
File: tokio-util/src/io/mod.rs:17-17
Timestamp: 2025-10-30T14:46:01.443Z
Learning: In tokio-util, the entire `io` module at `tokio-util/src/lib.rs` is already gated with `cfg_io!` macro, which applies `#[cfg(feature = "io")]` to all contents. Submodules declared within `tokio-util/src/io/mod.rs` inherit this feature gate and don't need additional `cfg_io!` wrapping unless they have specific requirements. The `cfg_io_util!` macro in the same file is for items that specifically require the `io-util` feature, not the general `io` feature.
🧬 Code graph analysis (1)
tokio/src/fs/read_to_string.rs (2)
tokio/src/fs/read_uring.rs (1)
read_uring(19-37)tokio/src/runtime/handle.rs (1)
current(144-148)
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)
- GitHub Check: Cursor Bugbot
- GitHub Check: claude-review
🔇 Additional comments (2)
tokio/src/fs/read_to_string.rs (2)
57-59: LGTM!The helper function correctly converts the borrowed path to an owned
PathBufbefore passing toasyncify, maintaining the existing spawn_blocking behavior.
27-28: LGTM!Borrowing the path upfront (
path.as_ref()) is a clean optimization that defers the allocation until the spawn_blocking path needs it, while allowing io-uring to work with the borrowed reference directly.
| let handle = crate::runtime::Handle::current(); | ||
| let driver_handle = handle.inner.driver().io(); | ||
| if driver_handle.check_and_init()? { | ||
| return read_uring(path).await.and_then(|vec| { | ||
| String::from_utf8(vec).map_err(|_| { | ||
| io::Error::new( | ||
| io::ErrorKind::InvalidData, | ||
| "stream did not contain valid UTF-8", | ||
| ) | ||
| }) | ||
| }); | ||
| } |
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🏁 Script executed:
#!/bin/bash
# Check how check_and_init() is used elsewhere and what errors it can return
rg -n -C5 'check_and_init' --type rustRepository: martin-augment/tokio
Length of output: 4919
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#!/bin/bash
# Look for try_init implementation and understand error handling
rg -n -B2 -A15 'fn try_init' --type rust | head -80Repository: martin-augment/tokio
Length of output: 2735
🏁 Script executed:
#!/bin/bash
# Check the error message in read_to_string.rs
sed -n '35,55p' tokio/src/fs/read_to_string.rsRepository: martin-augment/tokio
Length of output: 682
Update error message terminology from "stream" to "file".
The error message at line 47 says "stream did not contain valid UTF-8", but this is file I/O — it should say "file did not contain valid UTF-8" for consistency and accuracy.
🤖 Prompt for AI Agents
In tokio/src/fs/read_to_string.rs around lines 40 to 51, the error message
returned on UTF-8 conversion uses the word "stream" but this is file I/O; update
the io::Error message text to say "file did not contain valid UTF-8" instead of
"stream did not contain valid UTF-8" so the wording is accurate and consistent.
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value:useful; category:bug; feedback:The CodeRabbit AI reviewer is correct! The original error is ignored and a new error message is used. Utf8Error's Display impl is better because it knows when the bytes contain invalid data or incomplete utf8 sequence. Also using "stream" here is not correct because there is no streaming at all. Prevents returning a misleading error message in case of a utf8 related problem.
value:useful; category:bug; feedback:The Claude AI reviewer is correct! The original error is ignored and a new error message is used. Utf8Error's Display impl is better because it knows when the bytes contain invalid data or incomplete utf8 sequence. Also using "stream" here is not correct because there is no streaming at all. Prevents returning a misleading error message in case of a utf8 related problem. |
value:good-to-have; category:documentation; feedback:The Claude AI reviewer is correct! The documentation needs to be updated that if Linux IO_Uring is enabled then no new thread will be spawned. Prevents releasing an obsolete rustdoc for the read_to_string function. |
value:good-to-have; category:documentation; feedback:The CodeRabbit AI reviewer is correct! The documentation needs to be updated that if Linux IO_Uring is enabled then no new thread will be spawned. Prevents releasing an obsolete rustdoc for the read_to_string function. |
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7793: To review by AI