Moved the method to validate bases and poviders to snap package and renamed to ValidateBasesAndProviders.

2 files changed, 56 insertions, 0 deletions

diff --git a/snap/validate.go b/snap/validate.go
index 148fa2578a..7c24b56821 100644
--- a/snap/validate.go
+++ b/snap/validate.go
@@ -951,3 +951,43 @@ func ValidateSystemUsernames(info *Info) error {
	}
	return nil
 }
+
+// neededDefaultProviders returns the names of all default-providers for
+// the content plugs that the given snap.Info needs.
+func NeededDefaultProviders(info *Info) (cps []string) {
+	for _, plug := range info.Plugs {
+	if plug.Interface == "content" {
+	var dprovider string
+	if err := plug.Attr("default-provider", &dprovider); err == nil && dprovider != "" {
+	cps = append(cps, dprovider)
+	}
+	}
+	}
+	return cps
+}
+
+// ValidateBasesAndProviders checks that all bases/default-providers are part of the seed
+func ValidateBasesAndProviders(snapInfos map[string]*Info) []error {
+	var errs []error
+	for _, info := range snapInfos {
+	// ensure base is available
+	if info.Base != "" && info.Base != "none" {
+	if _, ok := snapInfos[info.Base]; !ok {
+	errs = append(errs, fmt.Errorf("cannot use snap %q: base %q is missing", info.InstanceName(), info.Base))
+	}
+	}
+	// ensure core is available
+	if info.Base == "" && info.SnapType == TypeApp && info.InstanceName() != "snapd" {
+	if _, ok := snapInfos["core"]; !ok {
+	errs = append(errs, fmt.Errorf(`cannot use snap %q: required snap "core" missing`, info.InstanceName()))
+	}
+	}
+	// ensure default-providers are available
+	for _, dp := range NeededDefaultProviders(info) {
+	if _, ok := snapInfos[dp]; !ok {
+	errs = append(errs, fmt.Errorf("cannot use snap %q: default provider %q is missing", info.InstanceName(), dp))
+	}
+	}
+	}
+	return errs
+}
diff --git a/snap/validate_test.go b/snap/validate_test.go
index ecd73bd61b..de74e2c856 100644
--- a/snap/validate_test.go
+++ b/snap/validate_test.go
@@ -1574,3 +1574,19 @@ system-usernames:
	err = Validate(info)
	c.Assert(err, ErrorMatches, `invalid system username "b@d"`)
 }
+
+func (s *ValidateSuite) TestNeededDefaultProviders(c *C) {
+	const yaml = `name: need-df
+version: 1.0
+plugs:
+ gtk-3-themes:
+ interface: content
+ default-provider: gtk-common-themes
+`
+	strk := NewScopedTracker()
+	info, err := InfoFromSnapYamlWithSideInfo([]byte(yaml), nil, strk)
+	c.Assert(err, IsNil)
+
+	dps := NeededDefaultProviders(info)
+	c.Check(dps, DeepEquals, []string{"gtk-common-themes"})
+}