Fix builder inconsistent error on buggy platform

When pulling an image by platform, it is possible for the image's
configured platform to not match what was in the manifest list.
The image itself is buggy because either the manifest list is incorrect
or the image config is incorrect. In any case, this is preventing people
from upgrading because many times users do not have control over these
buggy images.

This was not a problem in 19.03 because we did not compare on platform
before. It just assumed if we had the image it was the one we wanted
regardless of platform, which has its own problems.

Example Dockerfile that has this problem:

```Dockerfile
FROM --platform=linux/arm64 k8s.gcr.io/build-image/debian-iptables:buster-v1.3.0
RUN echo hello
```

This fails the first time you try to build after it finishes pulling but
before performing the `RUN` command.
On the second attempt it works because the image is already there and
does not hit the code that errors out on platform mismatch (Actually it
ignores errors if an image is returned at all).

Must be run with the classic builder (DOCKER_BUILDKIT=0).

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

daemon/images/image_builder.go

@@ -5,18 +5,23 @@ import (
 	"io"
 	"runtime"
 
+	"github.com/containerd/containerd/platforms"
 	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/backend"
 	"github.com/docker/docker/builder"
+	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/image"
 	"github.com/docker/docker/layer"
 	"github.com/docker/docker/pkg/containerfs"
+	"github.com/docker/docker/pkg/progress"
+	"github.com/docker/docker/pkg/streamformatter"
 	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/registry"
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
 type roLayer struct {
@@ -161,7 +166,29 @@ func (i *ImageService) pullForBuilder(ctx context.Context, name string, authConf
 	if err := i.pullImageWithReference(ctx, ref, platform, nil, pullRegistryAuth, output); err != nil {
 		return nil, err
 	}
-	return i.GetImage(name, platform)
+
+	img, err := i.GetImage(name, platform)
+	if errdefs.IsNotFound(err) && img != nil && platform != nil {
+		imgPlat := specs.Platform{
+			OS:           img.OS,
+			Architecture: img.BaseImgArch(),
+			Variant:      img.BaseImgVariant(),
+		}
+
+		p := *platform
+		if !platforms.Only(p).Match(imgPlat) {
+			po := streamformatter.NewJSONProgressOutput(output, false)
+			progress.Messagef(po, "", `
+WARNING: Pulled image with specified platform (%s), but the resulting image's configured platform (%s) does not match.
+This is most likely caused by a bug in the build system that created the fetched image (%s).
+Please notify the image author to correct the configuration.`,
+				platforms.Format(p), platforms.Format(imgPlat), name,
+			)
+			logrus.WithError(err).WithField("image", name).Warn("Ignoring error about platform mismatch where the manifest list points to an image whose configuration does not match the platform in the manifest.")
+			err = nil
+		}
+	}
+	return img, err
 }
 
 // GetImageAndReleasableLayer returns an image and releaseable layer for a reference or ID.