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api/types: use "omitzero" instead of "omitempty" for "netip" fields#51932

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thaJeztah merged 1 commit intomoby:masterfrom
thaJeztah:api_omitzero
Jan 26, 2026
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api/types: use "omitzero" instead of "omitempty" for "netip" fields#51932
thaJeztah merged 1 commit intomoby:masterfrom
thaJeztah:api_omitzero

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@thaJeztah thaJeztah commented Jan 26, 2026 •
edited by vvoland
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Pull request 50956 (88adc28) updated various types in the API module from a string to a netip.Prefix or netip.Addr. A side-effect of this was that zero values would no longer be omitted, and instead marshaled as an empty string;

package main

import (
    "encoding/json"
    "fmt"
    "net/netip"
)

type Foo struct {
    OmitEmpty netip.Prefix `json:",omitempty"`
    OmitZero  netip.Prefix `json:",omitzero"`
}

func main() {
    out, _ := json.Marshal(Foo{})
    fmt.Println(string(out))
}

The above produces {"OmitEmpty":""}, not omitting the empty address.

This patch;

  • updates most types to use omitzero instead of omitempty.
  • adds explicit json names to fields.

There's one type remaining that uses omitzero, but it's generated by go-swagger, which currently doesn't support omitzero; the PortSummary.IP;

moby/api/types/container/port_summary.go

Lines 12 to 20 in 335f605

// PortSummary Describes a port-mapping between the container and the host.
//
// Example: {"PrivatePort":8080,"PublicPort":80,"Type":"tcp"}
//
// swagger:model PortSummary
type PortSummary struct {
// Host IP address that the container's port is mapped to
IP netip.Addr `json:"IP,omitempty"`

- What I did

- How I did it

- How to verify it

docker network create foo
docker run -d --name foo --network name=foo,ip=172.19.0.10 nginx:alpine

Before this patch:

docker container inspect foo | jq .[].NetworkSettings.Networks.foo.IPAMConfig
{
  "IPv4Address": "172.19.0.10",
  "IPv6Address": ""
}

With this patch:

docker container inspect foo | jq .[].NetworkSettings.Networks.foo.IPAMConfig
{
  "IPv4Address": "172.19.0.10"
}

- Human readable description for the release notes

Fix some empty fields not being omitted in API responses.

- A picture of a cute animal (not mandatory but encouraged)

@thaJeztah
api/types: use "omitzero" instead of "omitempty" for "netip" fields
62c1a71 
Pull request 50956 (88adc28) updated
various types in the API module from a string to a `netip.Prefix` or
`netip.Addr`. A side-effect of this was that zero values would no longer
be omitted, and instead marshaled as an empty string;

    package main

    import (
        "encoding/json"
        "fmt"
        "net/netip"
    )

    type Foo struct {
        OmitEmpty netip.Prefix `json:",omitempty"`
        OmitZero  netip.Prefix `json:",omitzero"`
    }

    func main() {
        out, _ := json.Marshal(Foo{})
        fmt.Println(string(out))
    }

The above produces `{"OmitEmpty":""}`, not omitting the empty address.

This patch;

- updates most types to use `omitzero` instead of `omitempty`.
- adds explicit `json` names to fields.

There's one type remaining that uses `omitzero`, but it's generated by
go-swagger, which currently doesn't support `omitzero`; the `PortSummary.IP`;
https://github.com/moby/moby/blob/335f60509fde10cf8a148ef96f67faeba6517a4b/api/types/container/port_summary.go#L12-L20

Signed-off-by: Sebastiaan van Stijn <[email protected]>
@thaJeztah thaJeztah added this to the 29.2.0 milestone Jan 26, 2026
@thaJeztah thaJeztah mentioned this pull request Jan 26, 2026
Closed
@thaJeztah thaJeztah merged commit 31ffe93 into moby:master Jan 26, 2026
331 of 338 checks passed
@thaJeztah thaJeztah deleted the api_omitzero branch January 26, 2026 16:52
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@vvoland vvoland vvoland approved these changes

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docker network inspect ipam config with empty IPRange

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