index.md

title	tagline	description
Unexpected Go	Golang code with unexpected behaviors	Showcase of unexpected golang behaviors

This small site is oriented to developers learning golang that want to see the unexpected, at least for a newcomer, behaviors in the language.

This examples expect that reader is familiar with the language, if you're not familiar with it, you should complete the Go by Example tutorial.

Examples

The WIP list of examples is (with no specific order):

• nil errors that are non-nil errors
• time.RFC3339 constant is not a valid RFC3339 timestamp
• os.Stdout changes after init() in testable examples
• Write([]byte) (int, error) should not retain the slice
• if err := recover(); err != nil does not recover from all panics
• json.Unmarhsal merges structs and slices, but not map values
• defer does not wait for parallelized tests
• Benchmarks with very long setup run faster in sub-benchmarks
• clear() built-in function removes map keys but keeps slice indexes
• You can't remove a NaN key from a map without clearing it
• Generic type T any cannot be nil

Grab some popcorn

Disclaimer

This examples are not trying to prove that golang is wrong, it's just sharing stuff that someone who has just started learning the language doesn't expect.

Outdated / fixed items

These items have been updated, fixed or changed in the language, but are kept here for historical reasons:

• Outdated since 1.21: there's no math.Min(int, int) int function
• Outdated since 1.22: goroutines on for loop values