On WindowsPC, not build arm64 but amd64

[Yuhta28]

finch-support-20250309172011.zip

Describe the bug
I run finch on a Windows PC(x86_64) and try to build my Dockerfile in arm64 format with option --platform=64 and the container image is built in amd64 format even if I build with options.

Steps to reproduce

 uname -ms
Windows_NT x86_64 

 cat .\Dockerfile
FROM debian:stable-slim
RUN apt update && apt install -y curl ca-certificates gnupg

 finch build . -f .\Dockerfile -t finch-test:arm64 --platform=arm64
mux_client_request_session: read from master failed: Connection reset by peer
ControlSocket C:/Program Files/Finch/lima/data/finch/ssh.sock already exists, disabling multiplexing
[+] Building 2.3s (6/6) FINISHED
 => [internal] load build definition from Dockerfile                                                                         0.0s
 => => transferring dockerfile: 121B                                                                                         0.0s
 => [internal] load metadata for docker.io/library/debian:stable-slim                                                        1.5s
 => [internal] load .dockerignore                                                                                            0.0s
 => => transferring context: 2B                                                                                              0.0s
 => [1/2] FROM docker.io/library/debian:stable-slim@sha256:5484adc33b4c352c5a9f4c4ae295fc49aed1cb54a7a0712a1b29674fb6f4f10f  0.0s
 => => resolve docker.io/library/debian:stable-slim@sha256:5484adc33b4c352c5a9f4c4ae295fc49aed1cb54a7a0712a1b29674fb6f4f10f  0.0s
 => CACHED [2/2] RUN apt update && apt install -y curl ca-certificates gnupg                                                 0.0s
 => exporting to image                                                                                                       0.6s
 => => exporting layers                                                                                                      0.0s
 => => exporting manifest sha256:f1ba36fc1d1822524dae29985f0ef6f862d0d44bca0eeb7304ad02c65306670a                            0.0s
 => => exporting config sha256:f0b4db78fd4815d1c8b32528850f9a33d7eb1918607ac596e6b32b10b6be8f2f                              0.0s
 => => naming to docker.io/library/finch-test:arm64                                                                          0.0s
 => => unpacking to docker.io/library/finch-test:arm64            

 finch image ls
mux_client_request_session: read from master failed: Connection reset by peer
ControlSocket C:/Program Files/Finch/lima/data/finch/ssh.sock already exists, disabling multiplexing
REPOSITORY    TAG      IMAGE ID        CREATED           PLATFORM       SIZE       BLOB SIZE
finch-test    arm64    f1ba36fc1d18    19 seconds ago    linux/amd64    130.9MB    53.44MB

Expected behavior
I was expecting a contaimer image in arm64 format to be built.

finch image ls
mux_client_request_session: read from master failed: Connection reset by peer
ControlSocket C:/Program Files/Finch/lima/data/finch/ssh.sock already exists, disabling multiplexing
REPOSITORY    TAG      IMAGE ID        CREATED           PLATFORM       SIZE       BLOB SIZE
finch-test    arm64    f1ba36fc1d18    19 seconds ago    linux/arm64    130.9MB    53.44MB

Screenshots or logs
If applicable, add screenshots or logs to help explain your problem.

Additional context
Strangely enough, when I run a container image that has been saved directly to the registry using the run command, an arm64 container was launched.

finch run --rm --platform=arm64 public.ecr.aws/amazonlinux/amazonlinux uname -ms
mux_client_request_session: read from master failed: Connection reset by peer
ControlSocket C:/Program Files/Finch/lima/data/finch/ssh.sock already exists, disabling multiplexing
public.ecr.aws/amazonlinux/amazonlinux:latest:                                    resolved       |++++++++++++++++++++++++++++++++++++++|
index-sha256:558e465c865f94ba15dd832dfa418eb21e2a954dac7d5e542ac1fee146b7675c:    done           |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:a4c24d335f1a0742bbab3211c2afd6265f2f312f32f31af33b08e4a5d186730b: done           |++++++++++++++++++++++++++++++++++++++|
config-sha256:947f030348d9537ae55196975cf5930f93a9dd33ce8eb2f7d2e5a5b8d740cc11:   done           |++++++++++++++++++++++++++++++++++++++|
layer-sha256:a8ae4757b69337068f85c03c42e1020f67d8e126d57f500162c47221848c93bd:    done           |++++++++++++++++++++++++++++++++++++++|
elapsed: 5.2 s                                                                    total:  49.8 M (9.6 MiB/s)

Linux aarch64

 finch image ls
mux_client_request_session: read from master failed: Connection reset by peer
ControlSocket C:/Program Files/Finch/lima/data/finch/ssh.sock already exists, disabling multiplexing
REPOSITORY                                TAG       IMAGE ID        CREATED           PLATFORM       SIZE       BLOB SIZE
public.ecr.aws/amazonlinux/amazonlinux    latest    558e465c865f    30 seconds ago    linux/arm64    198.1MB    52.25MB

To help debug the issue as quickly as possible, we recommend generating a support bundle with finch support-bundle generate and attaching it to this issue. This packages all Finch-related configs and logs into one file.

[Shubhranshu153]

The parsing of the platform flag is incorrect leading to inaccurate results.

shell --workdir /mnt/c/Users/mahap/Documents/build-test finch sudo -E nerdctl image build . -f /mnt/c/Users/mahap/Documents/build-test/Dockerfile -t finch-test:arm64 /mnt/c/Users/mahap/Documents/build-test/--platform=arm64]