fix: build single-arch images compatibly with apko CLI

Signed-off-by: Jason Hall <jason@chainguard.dev>

internal/provider/build.go

@@ -202,17 +202,6 @@ func doBuild(ctx context.Context, data BuildResourceModel) (v1.Hash, coci.Signed
 	if err := errg.Wait(); err != nil {
 		return v1.Hash{}, nil, nil, err
 	}
-	// If we built a final image, then return that instead of wrapping it in an
-	// image index.
-	if len(imgs) == 1 {
-		for _, img := range imgs {
-			h, err := img.Digest()
-			if err != nil {
-				return v1.Hash{}, nil, nil, err
-			}
-			return h, img, sboms, nil
-		}
-	}
 
 	// generate the index
 	finalDigest, idx, err := oci.GenerateIndex(ctx, *ic2, imgs)

internal/provider/resource_build_test.go

@@ -224,7 +224,7 @@ resource "apko_build" "foo" {
 				resource.TestCheckResourceAttr("apko_build.foo", "repo", repostr),
 				resource.TestCheckResourceAttr("apko_build.foo", "image_ref",
 					// With pinned packages we should always get this digest.
-					repo.Digest("sha256:14f90e68f2603e992cc51916cc70113b1037bc2c5c6566ca26fec292753f3360").String()),
+					repo.Digest("sha256:a753adeb6de448f76e829c3d09deabdc9c183f30242b78e42d4c65ada17aa607").String()),
 
 				// Check that the build's amd64 predicate exists, the digest
 				// matches, and the creation timestamp is what we expect.
@@ -293,7 +293,7 @@ resource "apko_build" "foo" {
 				resource.TestCheckResourceAttr("apko_build.foo", "repo", repostr),
 				resource.TestCheckResourceAttr("apko_build.foo", "image_ref",
 					// With pinned packages we should always get this digest.
-					repo.Digest("sha256:7ecfd5ca0cec575e96ff46bf53284950ee80e5d1211cba47a51189debe41c79a").String()),
+					repo.Digest("sha256:8cee7e4467cc4361cc0754255fb93856eb14a0ecddafc247d1babf79a41d2e1c").String()),
 
 				// Check that the build's amd64 predicate exists, the digest
 				// matches, and the creation timestamp is what we expect.