ci: Add error message format check (#901)

Relevant issue(s)
Resolves #161

Description
This PR adds a linter rule that checks for proper formatting of the error message.

api/http/errors_test.go

@@ -139,7 +139,7 @@ func TestHandleErrOnDefault(t *testing.T) {
 	t.Cleanup(CleanupEnv)
 	env = "dev"
 	f := func(rw http.ResponseWriter, req *http.Request) {
-		handleErr(req.Context(), rw, errors.New("Unauthorized"), http.StatusUnauthorized)
+		handleErr(req.Context(), rw, errors.New("unauthorized"), http.StatusUnauthorized)
 	}
 	req, err := http.NewRequest("GET", "/test", nil)
 	if err != nil {
@@ -164,6 +164,6 @@ func TestHandleErrOnDefault(t *testing.T) {
 
 	assert.Equal(t, http.StatusUnauthorized, errResponse.Errors[0].Extensions.Status)
 	assert.Equal(t, http.StatusText(http.StatusUnauthorized), errResponse.Errors[0].Extensions.HTTPError)
-	assert.Equal(t, "Unauthorized", errResponse.Errors[0].Message)
-	assert.Contains(t, errResponse.Errors[0].Extensions.Stack, "[DEV] Unauthorized")
+	assert.Equal(t, "unauthorized", errResponse.Errors[0].Message)
+	assert.Contains(t, errResponse.Errors[0].Extensions.Stack, "[DEV] unauthorized")
 }

client/dockey.go

@@ -56,7 +56,7 @@ func NewDocKeyV0(dataCID cid.Cid) DocKey {
 func NewDocKeyFromString(key string) (DocKey, error) {
 	parts := strings.SplitN(key, "-", 2)
 	if len(parts) != 2 {
-		return DocKey{}, errors.New("Malformed DocKey, missing either version or cid")
+		return DocKey{}, errors.New("malformed DocKey, missing either version or cid")
 	}
 	versionStr := parts[0]
 	_, data, err := mbase.Decode(versionStr)
@@ -69,7 +69,7 @@ func NewDocKeyFromString(key string) (DocKey, error) {
 		return DocKey{}, err
 	}
 	if _, ok := ValidDocKeyVersions[uint16(version)]; !ok {
-		return DocKey{}, errors.New("Invalid DocKey version")
+		return DocKey{}, errors.New("invalid DocKey version")
 	}
 
 	uuid, err := uuid.FromString(parts[1])

client/document.go

@@ -89,7 +89,7 @@ func NewDocFromMap(data map[string]any) (*Document, error) {
 		delete(data, "_key") // remove the key so it isn't parsed further
 		kstr, ok := k.(string)
 		if !ok {
-			return nil, errors.New("Provided _key in document must be a string type")
+			return nil, errors.New("provided _key in document must be a string type")
 		}
 		if doc.key, err = NewDocKeyFromString(kstr); err != nil {
 			return nil, err

client/errors.go

@@ -24,13 +24,13 @@ const (
 var (
 	ErrFieldNotExist         = errors.New(errFieldNotExist)
 	ErrSelectOfNonGroupField = errors.New(errSelectOfNonGroupField)
-	ErrFieldNotObject        = errors.New("Trying to access field on a non object type")
-	ErrValueTypeMismatch     = errors.New("Value does not match indicated type")
-	ErrIndexNotFound         = errors.New("No index found for given ID")
-	ErrDocumentNotFound      = errors.New("No document for the given key exists")
-	ErrInvalidUpdateTarget   = errors.New("The target document to update is of invalid type")
-	ErrInvalidUpdater        = errors.New("The updater of a document is of invalid type")
-	ErrInvalidDeleteTarget   = errors.New("The target document to delete is of invalid type")
+	ErrFieldNotObject        = errors.New("trying to access field on a non object type")
+	ErrValueTypeMismatch     = errors.New("value does not match indicated type")
+	ErrIndexNotFound         = errors.New("no index found for given ID")
+	ErrDocumentNotFound      = errors.New("no document for the given key exists")
+	ErrInvalidUpdateTarget   = errors.New("the target document to update is of invalid type")
+	ErrInvalidUpdater        = errors.New("the updater of a document is of invalid type")
+	ErrInvalidDeleteTarget   = errors.New("the target document to delete is of invalid type")
 )
 
 func NewErrFieldNotExist(name string) error {

core/crdt/composite.go

@@ -135,7 +135,7 @@ func (c CompositeDAG) DeltaDecode(node ipld.Node) (core.Delta, error) {
 	delta := &CompositeDAGDelta{}
 	pbNode, ok := node.(*dag.ProtoNode)
 	if !ok {
-		return nil, errors.New("Failed to cast ipld.Node to ProtoNode")
+		return nil, errors.New("failed to cast ipld.Node to ProtoNode")
 	}
 	data := pbNode.Data()
 	h := &codec.CborHandle{}

core/crdt/lwwreg.go

@@ -139,7 +139,7 @@ func (reg LWWRegister) Merge(ctx context.Context, delta core.Delta, id string) e
 func (reg LWWRegister) setValue(ctx context.Context, val []byte, priority uint64) error {
 	curPrio, err := reg.getPriority(ctx, reg.key)
 	if err != nil {
-		return errors.Wrap("Failed to get priority for Set ", err)
+		return errors.Wrap("failed to get priority for Set ", err)
 	}
 
 	// if the current priority is higher ignore put
@@ -159,7 +159,7 @@ func (reg LWWRegister) setValue(ctx context.Context, val []byte, priority uint64
 	buf := append([]byte{byte(client.LWW_REGISTER)}, val...)
 	err = reg.store.Put(ctx, valueK.ToDS(), buf)
 	if err != nil {
-		return errors.Wrap("Failed to store new value ", err)
+		return errors.Wrap("failed to store new value ", err)
 	}
 
 	return reg.setPriority(ctx, reg.key, priority)
@@ -172,7 +172,7 @@ func (reg LWWRegister) DeltaDecode(node ipld.Node) (core.Delta, error) {
 	delta := &LWWRegDelta{}
 	pbNode, ok := node.(*dag.ProtoNode)
 	if !ok {
-		return nil, errors.New("Failed to cast ipld.Node to ProtoNode")
+		return nil, errors.New("failed to cast ipld.Node to ProtoNode")
 	}
 	data := pbNode.Data()
 	h := &codec.CborHandle{}

core/key.go

@@ -432,7 +432,7 @@ func (k DataStoreKey) PrefixEnd() DataStoreKey {
 func (k DataStoreKey) FieldID() (uint32, error) {
 	fieldID, err := strconv.Atoi(k.FieldId)
 	if err != nil {
-		return 0, errors.Wrap("Failed to get FieldID of Key", err)
+		return 0, errors.Wrap("failed to get FieldID of Key", err)
 	}
 	return uint32(fieldID), nil
 }

core/replicated.go

@@ -21,7 +21,7 @@ import (
 
 var (
 	// ErrMismatchedMergeType - Tying to merge two ReplicatedData of different types
-	ErrMismatchedMergeType = errors.New("Given type to merge does not match source")
+	ErrMismatchedMergeType = errors.New("given type to merge does not match source")
 )
 
 // ReplicatedData is a data type that allows concurrent writers

db/base/collection_keys.go

@@ -46,7 +46,7 @@ func MakePrimaryIndexKeyForCRDT(
 		fieldKey := getFieldKey(c, key, fieldName)
 		return MakeCollectionKey(c).WithInstanceInfo(fieldKey), nil
 	}
-	return core.DataStoreKey{}, errors.New("Invalid CRDT type")
+	return core.DataStoreKey{}, errors.New("invalid CRDT type")
 }
 
 func getFieldKey(

db/collection.go

@@ -34,8 +34,8 @@ import (
 )
 
 var (
-	ErrDocumentAlreadyExists = errors.New("A document with the given dockey already exists")
-	ErrUnknownCRDTArgument   = errors.New("Invalid CRDT arguments")
+	ErrDocumentAlreadyExists = errors.New("a document with the given dockey already exists")
+	ErrUnknownCRDTArgument   = errors.New("invalid CRDT arguments")
 	ErrUnknownCRDT           = errors.New("")
 )
 
@@ -63,29 +63,29 @@ type collection struct {
 // NewCollection returns a pointer to a newly instanciated DB Collection
 func (db *db) newCollection(desc client.CollectionDescription) (*collection, error) {
 	if desc.Name == "" {
-		return nil, errors.New("Collection requires name to not be empty")
+		return nil, errors.New("collection requires name to not be empty")
 	}
 
 	if len(desc.Schema.Fields) == 0 {
-		return nil, errors.New("Collection schema has no fields")
+		return nil, errors.New("collection schema has no fields")
 	}
 
 	docKeyField := desc.Schema.Fields[0]
 	if docKeyField.Kind != client.FieldKind_DocKey || docKeyField.Name != "_key" {
-		return nil, errors.New("Collection schema first field must be a DocKey")
+		return nil, errors.New("collection schema first field must be a DocKey")
 	}
 
 	desc.Schema.FieldIDs = make([]uint32, len(desc.Schema.Fields))
 	for i, field := range desc.Schema.Fields {
 		if field.Name == "" {
-			return nil, errors.New("Collection schema field missing Name")
+			return nil, errors.New("collection schema field missing Name")
 		}
 		if field.Kind == client.FieldKind_None {
-			return nil, errors.New("Collection schema field missing FieldKind")
+			return nil, errors.New("collection schema field missing FieldKind")
 		}
 		if (field.Kind != client.FieldKind_DocKey && !field.IsObject()) &&
 			field.Typ == client.NONE_CRDT {
-			return nil, errors.New("Collection schema field missing CRDT type")
+			return nil, errors.New("collection schema field missing CRDT type")
 		}
 		desc.Schema.FieldIDs[i] = uint32(i)
 		desc.Schema.Fields[i].ID = client.FieldID(i)
@@ -122,7 +122,7 @@ func (db *db) CreateCollection(
 		return nil, err
 	}
 	if exists {
-		return nil, errors.New("Collection already exists")
+		return nil, errors.New("collection already exists")
 	}
 
 	colSeq, err := db.getSequence(ctx, core.COLLECTION)
@@ -181,7 +181,7 @@ func (db *db) CreateCollection(
 // GetCollection returns an existing collection within the database
 func (db *db) GetCollectionByName(ctx context.Context, name string) (client.Collection, error) {
 	if name == "" {
-		return nil, errors.New("Collection name can't be empty")
+		return nil, errors.New("collection name can't be empty")
 	}
 
 	key := core.NewCollectionKey(name)
@@ -233,7 +233,7 @@ func (db *db) GetCollectionBySchemaID(
 	schemaID string,
 ) (client.Collection, error) {
 	if schemaID == "" {
-		return nil, errors.New("Schema ID can't be empty")
+		return nil, errors.New("schema ID can't be empty")
 	}
 
 	key := core.NewCollectionSchemaKey(schemaID)
@@ -256,7 +256,7 @@ func (db *db) GetAllCollections(ctx context.Context) ([]client.Collection, error
 		KeysOnly: true,
 	})
 	if err != nil {
-		return nil, errors.Wrap("Failed to create collection prefix query", err)
+		return nil, errors.Wrap("failed to create collection prefix query", err)
 	}
 	defer func() {
 		if err := q.Close(); err != nil {

db/collection_delete.go

@@ -30,8 +30,8 @@ import (
 )
 
 var (
-	ErrDeleteTargetEmpty = errors.New("The doc delete targeter cannot be empty")
-	ErrDeleteEmpty       = errors.New("The doc delete cannot be empty")
+	ErrDeleteTargetEmpty = errors.New("the doc delete targeter cannot be empty")
+	ErrDeleteEmpty       = errors.New("the doc delete cannot be empty")
 )
 
 // DeleteWith deletes a target document. Target can be a Filter statement,
@@ -293,7 +293,7 @@ func (c *collection) applyFullDelete(
 	// Get all the heads (cids).
 	heads, _, err := headset.List(ctx)
 	if err != nil {
-		return errors.Wrap("Failed to get document heads", err)
+		return errors.Wrap("failed to get document heads", err)
 	}
 
 	dagDel := newDagDeleter(txn.DAGstore())

db/collection_test.go

@@ -101,7 +101,7 @@ func TestNewCollectionReturnsErrorGivenDuplicateSchema(t *testing.T) {
 	assert.NoError(t, err)
 
 	_, err = newTestCollectionWithSchema(ctx, db)
-	assert.Errorf(t, err, "Collection already exists")
+	assert.Errorf(t, err, "collection already exists")
 }
 
 func TestNewCollectionReturnsErrorGivenNoFields(t *testing.T) {
@@ -117,7 +117,7 @@ func TestNewCollectionReturnsErrorGivenNoFields(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema has no fields")
+	assert.EqualError(t, err, "collection schema has no fields")
 }
 
 func TestNewCollectionReturnsErrorGivenNoName(t *testing.T) {
@@ -133,7 +133,7 @@ func TestNewCollectionReturnsErrorGivenNoName(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection requires name to not be empty")
+	assert.EqualError(t, err, "collection requires name to not be empty")
 }
 
 func TestNewCollectionReturnsErrorGivenNoKeyField(t *testing.T) {
@@ -155,7 +155,7 @@ func TestNewCollectionReturnsErrorGivenNoKeyField(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema first field must be a DocKey")
+	assert.EqualError(t, err, "collection schema first field must be a DocKey")
 }
 
 func TestNewCollectionReturnsErrorGivenKeyFieldIsNotFirstField(t *testing.T) {
@@ -181,7 +181,7 @@ func TestNewCollectionReturnsErrorGivenKeyFieldIsNotFirstField(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema first field must be a DocKey")
+	assert.EqualError(t, err, "collection schema first field must be a DocKey")
 }
 
 func TestNewCollectionReturnsErrorGivenFieldWithNoName(t *testing.T) {
@@ -207,7 +207,7 @@ func TestNewCollectionReturnsErrorGivenFieldWithNoName(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema field missing Name")
+	assert.EqualError(t, err, "collection schema field missing Name")
 }
 
 func TestNewCollectionReturnsErrorGivenFieldWithNoKind(t *testing.T) {
@@ -232,7 +232,7 @@ func TestNewCollectionReturnsErrorGivenFieldWithNoKind(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema field missing FieldKind")
+	assert.EqualError(t, err, "collection schema field missing FieldKind")
 }
 
 func TestNewCollectionReturnsErrorGivenFieldWithNoType(t *testing.T) {
@@ -257,7 +257,7 @@ func TestNewCollectionReturnsErrorGivenFieldWithNoType(t *testing.T) {
 	}
 
 	_, err = db.CreateCollection(ctx, desc)
-	assert.EqualError(t, err, "Collection schema field missing CRDT type")
+	assert.EqualError(t, err, "collection schema field missing CRDT type")
 }
 
 func TestGetCollectionByName(t *testing.T) {
@@ -303,5 +303,5 @@ func TestGetCollectionByNameReturnsErrorGivenEmptyString(t *testing.T) {
 	assert.NoError(t, err)
 
 	_, err = db.GetCollectionByName(ctx, "")
-	assert.EqualError(t, err, "Collection name can't be empty")
+	assert.EqualError(t, err, "collection name can't be empty")
 }

db/collection_update.go

@@ -29,10 +29,10 @@ import (
 )
 
 var (
-	ErrUpdateTargetEmpty     = errors.New("The doc update targeter cannot be empty")
-	ErrUpdateEmpty           = errors.New("The doc update cannot be empty")
+	ErrUpdateTargetEmpty     = errors.New("the doc update targeter cannot be empty")
+	ErrUpdateEmpty           = errors.New("the doc update cannot be empty")
 	ErrInvalidMergeValueType = errors.New(
-		"The type of value in the merge patch doesn't match the schema",
+		"the type of value in the merge patch doesn't match the schema",
 	)
 )
 
@@ -604,7 +604,7 @@ func (c *collection) makeSelectionQuery(
 	switch fval := filter.(type) {
 	case string:
 		if fval == "" {
-			return nil, errors.New("Invalid filter")
+			return nil, errors.New("invalid filter")
 		}
 		var p *parser.Filter
 		p, err = parser.NewFilterFromString(fval)
@@ -615,10 +615,10 @@ func (c *collection) makeSelectionQuery(
 	case *mapper.Filter:
 		f = fval
 	default:
-		return nil, errors.New("Invalid filter")
+		return nil, errors.New("invalid filter")
 	}
 	if filter == "" {
-		return nil, errors.New("Invalid filter")
+		return nil, errors.New("invalid filter")
 	}
 	slct, err := c.makeSelectLocal(f, mapping)
 	if err != nil {
@@ -697,7 +697,7 @@ func (c *collection) getTargetKeyForPatchPath( //nolint:unused
 ) (string, error) {
 	_, length := splitPatchPath(path)
 	if length == 0 {
-		return "", errors.New("Invalid patch op path")
+		return "", errors.New("invalid patch op path")
 	}
 
 	return "", nil

db/db.go

@@ -38,9 +38,9 @@ var (
 	log = logging.MustNewLogger("defra.db")
 	// ErrDocVerification occurs when a documents contents fail the verification during a Create()
 	// call against the supplied Document Key.
-	ErrDocVerification = errors.New("The document verification failed")
+	ErrDocVerification = errors.New("the document verification failed")
 
-	ErrOptionsEmpty = errors.New("Empty options configuration provided")
+	ErrOptionsEmpty = errors.New("empty options configuration provided")
 )
 
 // make sure we match our client interface
@@ -198,11 +198,11 @@ func (db *db) GetRelationshipIdField(fieldName, targetType, thisType string) (st
 	rm := db.schema.Relations
 	rel := rm.GetRelationByDescription(fieldName, targetType, thisType)
 	if rel == nil {
-		return "", errors.New("Relation does not exists")
+		return "", errors.New("relation does not exists")
 	}
 	subtypefieldname, _, ok := rel.GetFieldFromSchemaType(targetType)
 	if !ok {
-		return "", errors.New("Relation is missing referenced field")
+		return "", errors.New("relation is missing referenced field")
 	}
 	return subtypefieldname, nil
 }