Rust
Rust Error Called Option Unwrap on a None Value Explained
The panic called Option unwrap on a None value means a value you assumed was present was not. See how to find the line, and six patterns that replace the unwrap.
7 min read
Topic
Tooling
rustup, Clippy, rust-analyzer, debuggers and Git habits that shave minutes off every working day.
Testing
Flaky Tests in Rust and Seven Usual Causes to Check
Seven usual causes of tests that pass and fail at random in Rust, with a check and a fix for each: shared state, ports, time, HashMap order, threads, files and the environment.
3 min read
Tooling
Rust Error Address Already in Use When Binding a Port
Binding a port that is taken fails with Address already in use, os error 98. Find the process holding it, handle TIME_WAIT and restarts, and fail with a useful message.
3 min read
Tooling
Debugging Deadlocks in Rust With Thread Dumps and Traces
A Rust program that hangs is often a deadlock. Capture every thread's stack with gdb, parking_lot deadlock detection or tokio-console, and read who waits for what.
3 min read
Tooling
Debugging Memory Errors in Unsafe Rust With Sanitizers
Find memory errors in unsafe Rust with AddressSanitizer, ThreadSanitizer and MemorySanitizer on nightly, and Miri for interpretation. Flags, build-std, output and limits.
2 min read
Tooling
Log Levels and What to Log in a Rust Service Explained
Choose log levels by who reads them and when: what belongs at error, warn, info, debug and trace in a Rust service, what never to log, and how much is too much.
3 min read
Tooling
Tracing Spans and Events Explained for Beginners Made Clear
Tracing replaces log lines with spans and events: a span is a period of work, an event is a moment. Learn the macros, fields, instrument, subscribers and filters.
2 min read
Tooling
Debugging a Stack Overflow in Rust and Recursion Limits
A Rust stack overflow aborts with thread main has overflowed its stack. Find the recursion or oversized local that caused it, then fix with a loop, a Vec, a Box or a bigger thread stack.
3 min read
ToolingGuide
Debugging Rust in VS Code With Codelldb Step by Step
Debug Rust in VS Code with the CodeLLDB extension: install, a launch.json, breakpoints, conditional breakpoints, watch expressions, debugging tests and common problems.
13 min read
Systems
Using Miri to Catch Undefined Behavior in Unsafe Rust
Miri interprets your tests and reports undefined behavior in unsafe code: out of bounds access, use after free, bad aliasing and uninitialized reads. Here is how to run and read it.
2 min read
ToolingGuide
Debugging Rust From Printing to Breakpoints and Backtraces
A map of Rust debugging tools in the order to reach for them: compiler messages, dbg!, tests, backtraces, tracing, a debugger and sanitizers, with when each one wins.
16 min read
PerformanceGuide
Memory Usage in Rust Services and Finding Leaks Step by Step
Find where a Rust service's memory goes: read RSS and allocator stats, profile allocations with dhat or heaptrack, tell a leak from growth, and fix the usual causes.
18 min read
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