2024-03-27 19:24:38 +01:00
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package src
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import "context"
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func example() {
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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 = context.WithValue(ctx, "other", "val")
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}
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for i := 0; i < 10; i++ {
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2024-03-27 23:50:12 +01:00
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ctx = context.WithValue(ctx, "key", i) // want "nested context in loop"
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2024-03-27 19:24:38 +01:00
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ctx = context.WithValue(ctx, "other", "val")
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}
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for item := range []string{"one", "two", "three"} {
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2024-03-27 23:50:12 +01:00
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ctx = wrapContext(ctx) // want "nested context in loop"
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2024-03-27 19:24:38 +01:00
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ctx := context.WithValue(ctx, "key", item)
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ctx = wrapContext(ctx)
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}
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for {
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2024-03-27 23:50:12 +01:00
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ctx = wrapContext(ctx) // want "nested context in loop"
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2024-03-27 19:24:38 +01:00
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break
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}
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}
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func wrapContext(ctx context.Context) context.Context {
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return context.WithoutCancel(ctx)
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}
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2024-05-29 16:47:58 +02:00
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// storing contexts in a struct isn't recommended, but local copies of a non-pointer struct should act like local copies of a context.
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func inStructs(ctx context.Context) {
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for i := 0; i < 10; i++ {
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c := struct{ Ctx context.Context }{ctx}
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c.Ctx = context.WithValue(c.Ctx, "key", i)
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c.Ctx = context.WithValue(c.Ctx, "other", "val")
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}
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for i := 0; i < 10; i++ {
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c := []struct{ Ctx context.Context }{{ctx}}
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c[0].Ctx = context.WithValue(c[0].Ctx, "key", i)
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c[0].Ctx = context.WithValue(c[0].Ctx, "other", "val")
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}
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c := struct{ Ctx context.Context }{ctx}
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for i := 0; i < 10; i++ {
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c := c
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c.Ctx = context.WithValue(c.Ctx, "key", i)
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c.Ctx = context.WithValue(c.Ctx, "other", "val")
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}
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pc := &struct{ Ctx context.Context }{ctx}
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for i := 0; i < 10; i++ {
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c := pc
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c.Ctx = context.WithValue(c.Ctx, "key", i) // want "nested context in loop"
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c.Ctx = context.WithValue(c.Ctx, "other", "val")
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}
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for i := 0; i < 10; i++ {
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c := []*struct{ Ctx context.Context }{{ctx}}
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c[0].Ctx = context.WithValue(c[0].Ctx, "key", i) // want "nested context in loop"
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c[0].Ctx = context.WithValue(c[0].Ctx, "other", "val")
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}
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}
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