buildconfig: disable tests for undecoded keys for now

This commit partially reverts PT#549 to unblock filesystem
customizations in bib.

This is a short term fix and we should revert and do something
smarter like osbuild/images#951 or see
if we can do better in the toml unmarshaling. But to unblock
toml customizations this is a (IMHO) reasonable first step.

Closes: osbuild#655

bib/internal/buildconfig/config.go

@@ -59,15 +59,11 @@ func decodeTomlBuildConfig(r io.Reader, what string) (*BuildConfig, error) {
 	dec := toml.NewDecoder(r)
 
 	var conf BuildConfig
-	metadata, err := dec.Decode(&conf)
+	_, err := dec.Decode(&conf)
 	if err != nil {
 		return nil, fmt.Errorf("cannot decode %q: %w", what, err)
 	}
 
-	if len(metadata.Undecoded()) > 0 {
-		return nil, fmt.Errorf("cannot decode %q: unknown keys found: %v", what, metadata.Undecoded())
-	}
-
 	return &conf, nil
 }
 

bib/internal/buildconfig/config_test.go

@@ -133,16 +133,6 @@ func TestReadLegacyJSONConfig(t *testing.T) {
 	assert.Equal(t, expectedBuildConfig, cfg)
 }
 
-func TestTomlUnknownKeysError(t *testing.T) {
-	fakeUserCnfPath := makeFakeConfig(t, "config.toml", `
-[[birds]]
-name = "toucan"
-`)
-	_, err := buildconfig.ReadWithFallback(fakeUserCnfPath)
-
-	assert.ErrorContains(t, err, "unknown keys found: [birds birds.name]")
-}
-
 func TestJsonUnknownKeysError(t *testing.T) {
 	fakeUserCnfPath := makeFakeConfig(t, "config.json", `
 {