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31 lines
523 B
Markdown
31 lines
523 B
Markdown
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# foreshadow
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`foreshadow` is a Go linter which detects un-shadowed contexts in loops.
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They can lead to performance issues, as documented here: https://gabnotes.org/fat-contexts/
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## Example
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```go
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package main
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import "context"
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func ok() {
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ctx := context.Background()
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for i := 0; i < 10; i++ {
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ctx := context.WithValue(ctx, "key", i)
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_ = ctx
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}
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}
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func notOk() {
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ctx := context.Background()
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for i := 0; i < 10; i++ {
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ctx = context.WithValue(ctx, "key", i) // "context not shadowed in loop"
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_ = ctx
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}
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}
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```
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