[backport] gateway2: use safer merging to avoid assuming zero values as being unset #10559
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The legacy Edge code uses ShallowMerge() which can undesirably overwrite zero values mistaking them for unset values. RouteOptions merging in GatewayV2 uses the same API, but this can result in undesirable effects if the merging considers zero valued fields as being unset. To avoid this, the options merging used by GatewayV2 relies on a safer merge that only allows merging of values that can be set to Nil (pointers, slices, maps, etc.) which works since all user-facing fields on the RouteOptions are nil-able. Functionally, this is the same as before due to all fields being nil-able but it affects how overwrites are counted, and is a bit clearer to readers. Moreover, trying to merge a non-nil field will panic which can catch potential misuse of the API. Signed-off-by: Shashank Ram <[email protected]>
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…as being unset (#10559) Signed-off-by: Shashank Ram <[email protected]>
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Backports #10555 to v1.18.x
The legacy Edge code uses ShallowMerge() which can undesirably overwrite zero values mistaking them for unset values. RouteOptions merging in GatewayV2 uses the same API, but this can result in undesirable effects if the merging considers zero valued fields as being unset. To avoid this, the options merging used by GatewayV2 relies on a safer merge that only allows merging of values that can be set to Nil (pointers, slices, maps, etc.) which works since all user-facing fields on the RouteOptions are nil-able. Functionally, this is the same as before due to all fields being nil-able but it affects how overwrites are counted, and is a bit clearer to readers. Moreover, trying to merge a non-nil field will panic which can catch potential misuse of the API.