馃悰 returned objects of reference type should be unchangeable #1851
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@mars1024: The
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| @@ -193,8 +193,8 @@ func indexByField(indexer Informer, field string, extractor client.IndexerFunc) | |||
| rawVals := extractor(obj) | |||
| var vals []string | |||
| if ns == "" { | |||
| // if we're not doubling the keys for the namespaced case, just re-use what was returned to us | |||
| vals = rawVals | |||
| // if we're not doubling the keys for the namespaced case, just create a new slice with same length | |||
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Sorry I don't understand. If you write a function that returns a pointer, you are not supposed to keep a reference to that pointer or its underlying value.
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Can you clarify why you are doing that?
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The story is, I compute and put the indexer values into the object status .status.indexerValues, so the extractor will be
func(obj client.Object) []string {
someObject, _ := obj.(*group.ObjectKind)
return someObject.Status.IndexerValues
}
As we know, the object from client cache should be unchangeable.
Just think another scene,
values := []string{"a", "b", "c"}
do(values)
doAgain(values)
Do we expect values will be changed by do? Then doAgain will get unexpected values.
Though slice(extractor return) is a pointer type here, but it is used because it contains immutable values, so I don't think it should be changed when being used.
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Slice(extractor return) here is more like a container containing immutable values(indexer values).
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Okay, can you then please add a test that covers this scenario?
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Of course, will do it ~
Signed-off-by: Bruce Ma <brucema19901024@gmail.com>
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test case added, PTAL @alvaroaleman @FillZpp , thanks! |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: alvaroaleman, mars1024 The full list of commands accepted by this bot can be found here. The pull request process is described here
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Signed-off-by: Bruce Ma brucema19901024@gmail.com
The returned slice of
extractorfunction is reference type, reusing it will bring unpredictable problems, it should be unchangeable.