Improve error handling for GetCredentialStateForProvider

The `GetCredentialStateForProvider` swallows an error since it was
originally written for a codepath where the error was not important.
Since then, it is used in a second place where the error is important.
I'm not sure if it's possible for the error to get triggered in
practice, but I managed to trigger the error path while writing unit
tests, which led to a strange and hard to debug error happening after
the error was skipped over.

Refactor this function to return an error. Ignore it in the call site
where it should be ignored, and react to it where it is significant. As
a nice side effect of this change, the control flow of
`GetCredentialStateForProvider` is significantly simplified.

Some unrelated unit test improvements from an ongoing development branch
have also been added to this branch.

internal/controlplane/handlers_providers.go

@@ -199,14 +199,20 @@ func protobufProviderFromDB(
 		}
 	}
 
+	state, err := providers.GetCredentialStateForProvider(ctx, *p, store, cryptoEngine, pc)
+	if err != nil {
+		// This is non-fatal
+		zerolog.Ctx(ctx).Error().Err(err).Str("provider", p.Name).Msg("error getting credential")
+	}
+
 	return &minderv1.Provider{
 		Name:             p.Name,
 		Project:          p.ProjectID.String(),
 		Version:          p.Version,
 		Implements:       protobufProviderImplementsFromDB(ctx, *p),
 		AuthFlows:        protobufProviderAuthFlowFromDB(ctx, *p),
 		Config:           cfg,
-		CredentialsState: providers.GetCredentialStateForProvider(ctx, *p, store, cryptoEngine, pc),
+		CredentialsState: state,
 		Class:            string(p.Class),
 	}, nil
 }

internal/db/provider_access_tokens_test.go

@@ -56,17 +56,21 @@ func TestUpsertProviderAccessToken(t *testing.T) {
 	require.Equal(t, secret, deserializeSecret(t, tok.EncryptedAccessToken))
 	require.Equal(t, sql.NullString{}, tok.OwnerFilter)
 
+	newSecret := createSecret(t, "def")
+	newSerialized := serializeSecret(t, newSecret)
 	tokUpdate, err := testQueries.UpsertAccessToken(context.Background(), UpsertAccessTokenParams{
-		ProjectID:      project.ID,
-		Provider:       prov.Name,
-		EncryptedToken: "def",
-		OwnerFilter:    sql.NullString{},
+		ProjectID:            project.ID,
+		Provider:             prov.Name,
+		EncryptedToken:       "def",
+		EncryptedAccessToken: newSerialized,
+		OwnerFilter:          sql.NullString{},
 	})
 
 	require.NoError(t, err)
 	require.Equal(t, project.ID, tokUpdate.ProjectID)
 	require.Equal(t, prov.Name, tokUpdate.Provider)
 	require.Equal(t, "def", tokUpdate.EncryptedToken)
+	require.Equal(t, newSecret, deserializeSecret(t, tokUpdate.EncryptedAccessToken))
 	require.Equal(t, sql.NullString{}, tokUpdate.OwnerFilter)
 	require.Equal(t, tok.ID, tokUpdate.ID)
 	require.Equal(t, tok.CreatedAt, tokUpdate.CreatedAt)

internal/providers/github/manager/manager.go

@@ -148,7 +148,10 @@ func (g *githubProviderManager) Build(ctx context.Context, config *db.Provider)
 }
 
 func (g *githubProviderManager) Delete(ctx context.Context, config *db.Provider) error {
-	state := providers.GetCredentialStateForProvider(ctx, *config, g.store, g.crypteng, g.config)
+	state, err := providers.GetCredentialStateForProvider(ctx, *config, g.store, g.crypteng, g.config)
+	if err != nil {
+		return fmt.Errorf("unable to get credential state for provider %s: %w", config.ID, err)
+	}
 	if state == v1.CredentialStateSet {
 		provider, err := g.Build(ctx, config)
 		if err != nil {

internal/providers/github/service/service_test.go

@@ -192,6 +192,10 @@ func TestProviderService_CreateGitHubOAuthProvider(t *testing.T) {
 	dbToken, err := mocks.fakeStore.GetAccessTokenByProvider(context.Background(), dbProv.Name)
 	require.NoError(t, err)
 	require.Len(t, dbToken, 1)
+	require.True(t, dbToken[0].EncryptedAccessToken.Valid)
+	deserialized, err := crypto.DeserializeEncryptedData(dbToken[0].EncryptedAccessToken.RawMessage)
+	require.NoError(t, err)
+	require.Equal(t, deserialized, encryptedToken)
 	require.Equal(t, dbToken[0].EncryptedToken, encryptedToken.EncodedData)
 	require.Equal(t, dbToken[0].OwnerFilter, sql.NullString{String: "testorg", Valid: true})
 	require.Equal(t, dbToken[0].EnrollmentNonce, sql.NullString{String: stateNonce, Valid: true})
@@ -229,6 +233,10 @@ func TestProviderService_CreateGitHubOAuthProvider(t *testing.T) {
 	dbTokenUpdate, err := mocks.fakeStore.GetAccessTokenByProvider(context.Background(), dbProv.Name)
 	require.NoError(t, err)
 	require.Len(t, dbTokenUpdate, 1)
+	require.True(t, dbToken[0].EncryptedAccessToken.Valid)
+	deserialized, err = crypto.DeserializeEncryptedData(dbToken[0].EncryptedAccessToken.RawMessage)
+	require.NoError(t, err)
+	require.Equal(t, deserialized, encryptedToken)
 	require.Equal(t, dbTokenUpdate[0].EncryptedToken, encryptedToken.EncodedData)
 	require.Equal(t, dbTokenUpdate[0].OwnerFilter, sql.NullString{String: "testorg", Valid: true})
 	require.Equal(t, dbTokenUpdate[0].EnrollmentNonce, sql.NullString{String: stateNonceUpdate, Valid: true})

internal/providers/manager/manager.go

@@ -176,7 +176,7 @@ func (p *providerManager) deleteByRecord(ctx context.Context, config *db.Provide
 	}
 
 	// carry out provider-specific cleanup
-	if err := manager.Delete(ctx, config); err != nil {
+	if err = manager.Delete(ctx, config); err != nil {
 		return fmt.Errorf("error while cleaning up provider: %w", err)
 	}
 

internal/providers/providers.go

@@ -78,30 +78,27 @@ func GetCredentialStateForProvider(
 	s db.Store,
 	cryptoEngine crypto.Engine,
 	provCfg *serverconfig.ProviderConfig,
-) string {
-	var credState string
+) (string, error) {
 	// if the provider doesn't support any auth flow
 	// credentials state is not applicable
 	if slices.Equal(prov.AuthFlows, []db.AuthorizationFlow{db.AuthorizationFlowNone}) {
-		credState = provinfv1.CredentialStateNotApplicable
-	} else {
-		credState = provinfv1.CredentialStateUnset
-		cred, err := getCredentialForProvider(ctx, prov, cryptoEngine, s, provCfg)
-		if err != nil {
-			// This is non-fatal
-			zerolog.Ctx(ctx).Error().Err(err).Str("provider", prov.Name).Msg("error getting credential")
-		} else {
-			// check if the credential is EmptyCredential
-			// if it is, then the state is not applicable
-			if _, ok := cred.(*credentials.EmptyCredential); ok {
-				credState = provinfv1.CredentialStateUnset
-			} else {
-				credState = provinfv1.CredentialStateSet
-			}
-		}
+		return provinfv1.CredentialStateNotApplicable, nil
+	}
+
+	cred, err := getCredentialForProvider(ctx, prov, cryptoEngine, s, provCfg)
+	if err != nil {
+		// One of the callers of this function treats this error as non-fatal
+		// and uses the credState value.
+		return provinfv1.CredentialStateUnset, err
+	}
+
+	// check if the credential is EmptyCredential
+	// if it is, then the state is not applicable
+	if _, ok := cred.(*credentials.EmptyCredential); ok {
+		return provinfv1.CredentialStateUnset, nil
 	}
 
-	return credState
+	return provinfv1.CredentialStateSet, nil
 }
 
 func getCredentialForProvider(