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Nested Assignments
Saturday, December 27, 2025 in Blog
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We finished the previous post with a riddle, so let’s start this one with another. What does the following code print? var ( a, b = 1, 2 c = &a ) c, *c = func() (*int, int) { c, a = &b, 3; a := b; return nil, a }() fmt.Println(a, b) Try …
Shadowing in Go
Monday, December 22, 2025 in Blog
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In the previous post, we discussed why minimizing identifier scope is beneficial for maintainable Go code. Tightly scoped variables reduce cognitive load and make refactoring easier. However, we might sometimes choose a slightly wider scope to reduce …
Minimize Identifier Scope in Go
Wednesday, November 19, 2025 in Blog
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Have you ever spent hours debugging a subtle issue, only to discover it was caused by a variable being accidentally reused 200 lines away from its declaration? Or found yourself scrolling up and down a long function, trying to track where a variable …
The Day the Linter Broke My Code
Monday, September 15, 2025 in Blog
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Another Story… Imagine you were given a task to design errors for your service. DataEOFError should contain the name of the data file and be considered equal to io.ErrUnexpectedEOF. ProcessingFailedError should contain a processing ID as a string and …
Understanding Go Error Types: Pointer vs. Value
Wednesday, August 13, 2025 in Blog
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A Small Story… Imagine you have to rewrite cluster autoscaling. There’s a function makeNodeSchedulable that rarely returns a CriticalAddonsOnlyError when that node has a CriticalAddonsOnly taint. The old code looks like this: makeSchedulableLoop: for …
A Zero-Sized Bug Hunt in golang.org/x/sync
Wednesday, July 02, 2025 in Blog
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… continued from the previous post. While researching the usage of zero-sized types in Go I wrote zerolint1 and the accompanying cmplint2 and examined over 500 popular Go projects. I want to look into some examples why I think those linters …
The Perils of Pointers in the Land of the Zero-Sized Type
Saturday, May 31, 2025 in Blog
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Imagine writing a translation function that transforms internal errors into public API errors. In the first iteration, you return nil when no translation takes place. You make a simple change — returning the original error instead of nil — and …
More Concurrency Bugs
Tuesday, April 16, 2024 in Blog
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More Real-world Usage Datadog has excellent software engineers. Nevertheless, it’s easy to find code with race conditions. Let’s examine a simplified version of waitForConfigsFromAD: 1package main 2 3import ( 4 "fmt" 5 …
Concurrency Bugs
Monday, April 15, 2024 in Blog
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Errors Observed in Real-world Usage In “Problems With Concurrency” I mentioned that I see concurrency issues a lot. Let’s look at something I recently found in production: 1package main 2 3func task() ([]int, error) { 4 // We want to calculate …
Java Structured Concurrency
Wednesday, April 10, 2024 in Blog
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… continued from the previous post. Structured Concurrency Preview I’ve written about structured concurrency, and Java has a preview API1 StructuredTaskScope2: 1import com.fillmore_labs.blog.jvt.Slow2; 2import …