On Thu, Jun 18, 2026 at 09:58:17 +0200, Michal Privoznik via Devel wrote:
> From: Michal Privoznik <[email protected]>
>
> The detach-interface virsh command requires domain (obviously)
> and --type to identify <interface/>. Optionally, --mac can be
> provided to chose from multiple interfaces. Well, that renders
> --type argument redundant. I mean, if there are but unique MACs
> within domain XML, then interface type is implied. If there are
> duplicate MACs then --type can help to differentiate, though at
> that point detach-device seems like a better fit.
>
> Long story short, make --type optional.
>
> Signed-off-by: Michal Privoznik <[email protected]>
> ---
> docs/manpages/virsh.rst | 2 +-
> tools/virsh-domain.c | 13 ++++++++++---
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
> index 39d91d8375..2992495ecb 100644
> --- a/docs/manpages/virsh.rst
> +++ b/docs/manpages/virsh.rst
> @@ -5586,7 +5586,7 @@ detach-interface
>
> ::
>
> - detach-interface domain type [--mac mac]
> + detach-interface domain [--type type] [--mac mac]
The syntax for an optional positional argument is: [<type>] per what our
help prints:
SYNOPSIS
detach-interface <domain> [<type>] [--mac <string>] [--persistent]
[--config] [--live] [--current] [--print-xml]
> [[[--live] [--config] | [--current]] | [--persistent]] [--print-xml]
>
> Detach a network interface from a domain.
> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> index f9de3b42a9..8a6f868e34 100644
> --- a/tools/virsh-domain.c
> +++ b/tools/virsh-domain.c
> @@ -12782,7 +12782,6 @@ static const vshCmdOptDef opts_detach_interface[] = {
> {.name = "type",
> .type = VSH_OT_STRING,
> .positional = true,
> - .required = true,
> .help = N_("network interface type")
> },
> {.name = "mac",
> @@ -12816,7 +12815,7 @@ virshDomainDetachInterface(char *doc,
> g_autoptr(xmlDoc) xml = NULL;
> g_autoptr(xmlXPathContext) ctxt = NULL;
> g_autofree char *detach_xml = NULL;
> - g_autofree char *xpath =
> g_strdup_printf("/domain/devices/interface[@type='%s']", type);
> + g_autofree char *xpath = NULL;
> g_autofree xmlNodePtr *nodes = NULL;
> ssize_t nnodes;
> xmlNodePtr matchNode = NULL;
> @@ -12827,8 +12826,16 @@ virshDomainDetachInterface(char *doc,
> return false;
> }
>
> + if (type)
> + xpath = g_strdup_printf("/domain/devices/interface[@type='%s']",
> type);
> + else
> + xpath = g_strdup("/domain/devices/interface");
> +
> if ((nnodes = virXPathNodeSet(xpath, ctxt, &nodes)) <= 0) {
> - vshError(ctl, _("No interface found whose type is %1$s"), type);
> + if (type)
> + vshError(ctl, _("No interface found whose type is %1$s"), type);
> + else
> + vshError(ctl, "%s", _("Domain has no interfaces"));
Looking at the code, if neither 'mac' nor 'type' are specified it
detaches the only interface if there's exactly one.
I think I'd reword the man page section:
Detach a network interface from a domain.
*type* can be either *network* to indicate a physical network device or
*bridge* to indicate a bridge to a device. It is recommended to use the
*mac* option to distinguish between the interfaces if more than one are
present on the domain.
to something like:
*type* and/or *mac* can be used to narrow
Detach a network interface from a domain.
In case when multiple interfaces are present in the *type* and/or
*--mac* must be used to narrow down the selection to 1 interface.
*type* can be either *network* to indicate a physical network device
*bridge* to indicate a bridge to a device.
*--mac* can select the interface based on the configured MAC address.
Reviewed-by: Peter Krempa <[email protected]>
