Error types should satisfy error interface instead of embedding error field.

internal/runbits/checkout/checkout.go

@@ -172,7 +172,7 @@ func CreateProjectFiles(checkoutPath, cachePath, owner, name, branch, commitID,
 		})
 		if err != nil {
 			if osutils.IsAccessDeniedError(err) {
-				return &ErrNoPermission{err, checkoutPath}
+				return &ErrNoPermission{checkoutPath}
 			}
 			return errs.Wrap(err, "Could not create projectfile")
 		}

internal/runbits/checkout/path.go

@@ -37,15 +37,21 @@ func (r *Checkout) pathToUse(namespace *project.Namespaced, preferredPath string
 }
 
 type ErrAlreadyCheckedOut struct {
-	error
 	Path string
 }
 
+func (e ErrAlreadyCheckedOut) Error() string {
+	return "already checked out"
+}
+
 type ErrNoPermission struct {
-	error
 	Path string
 }
 
+func (e ErrNoPermission) Error() string {
+	return "no permission"
+}
+
 func validatePath(ns *project.Namespaced, path string) error {
 	if !fileutils.TargetExists(path) {
 		return nil
@@ -61,7 +67,7 @@ func validatePath(ns *project.Namespaced, path string) error {
 
 	configFile := filepath.Join(path, constants.ConfigFileName)
 	if fileutils.FileExists(configFile) {
-		return &ErrAlreadyCheckedOut{errs.New("already checked out at %s", path), path}
+		return &ErrAlreadyCheckedOut{path}
 	}
 
 	return nil

internal/runbits/runtime/requirements/requirements.go

@@ -344,15 +344,18 @@ func (r *RequirementOperation) prepareBuildScript(bp *bpModel.BuildPlanner, pare
 }
 
 type ResolveNamespaceError struct {
-	error
 	Name string
 }
 
+func (e ResolveNamespaceError) Error() string {
+	return "unable to resolve namespace"
+}
+
 func (r *RequirementOperation) resolveNamespaces(ts *time.Time, requirements ...*Requirement) error {
 	for _, requirement := range requirements {
 		if err := r.resolveNamespace(ts, requirement); err != nil {
 			if err != errNoLanguage {
-				err = &ResolveNamespaceError{err, requirement.Name}
+				err = errs.Pack(err, &ResolveNamespaceError{requirement.Name})
 			}
 			return errs.Wrap(err, "Unable to resolve namespace")
 		}

internal/runners/artifacts/download.go

@@ -55,10 +55,13 @@ func NewDownload(prime primeable) *Download {
 }
 
 type errArtifactExists struct {
-	error
 	Path string
 }
 
+func (e errArtifactExists) Error() string {
+	return "artifact exists"
+}
+
 func rationalizeDownloadError(proj *project.Project, auth *authentication.Auth, err *error) {
 	var artifactExistsErr *errArtifactExists
 
@@ -137,7 +140,7 @@ func (d *Download) downloadArtifact(artifact *buildplan.Artifact, targetDir stri
 
 	downloadPath := filepath.Join(targetDir, basename)
 	if fileutils.TargetExists(downloadPath) {
-		return &errArtifactExists{Path: downloadPath}
+		return &errArtifactExists{downloadPath}
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())

internal/runners/initialize/init.go

@@ -73,10 +73,13 @@ type primeable interface {
 }
 
 type errProjectExists struct {
-	error
 	path string
 }
 
+func (e errProjectExists) Error() string {
+	return "project file already exists"
+}
+
 var errNoLanguage = errs.New("No language specified")
 
 type errUnrecognizedLanguage struct {
@@ -156,10 +159,7 @@ func (r *Initialize) Run(params *RunParams) (rerr error) {
 	}
 
 	if fileutils.TargetExists(filepath.Join(path, constants.ConfigFileName)) {
-		return &errProjectExists{
-			error: errs.New("Project file already exists"),
-			path:  path,
-		}
+		return &errProjectExists{path}
 	}
 
 	err := fileutils.MkdirUnlessExists(path)

internal/runners/pull/pull.go

@@ -45,11 +45,14 @@ type Pull struct {
 }
 
 type errNoCommonParent struct {
-	error
 	localCommitID  strfmt.UUID
 	remoteCommitID strfmt.UUID
 }
 
+func (e errNoCommonParent) Error() string {
+	return "no common parent"
+}
+
 type PullParams struct {
 	Force bool
 }
@@ -140,7 +143,6 @@ func (p *Pull) Run(params *PullParams) (rerr error) {
 
 		if commonParent == nil {
 			return &errNoCommonParent{
-				errs.New("no common parent"),
 				*localCommit,
 				*remoteCommit,
 			}

internal/runners/push/push.go

@@ -68,15 +68,21 @@ var (
 )
 
 type errProjectNameInUse struct {
-	error
 	Namespace *project.Namespaced
 }
 
+func (e errProjectNameInUse) Error() string {
+	return "project name in use"
+}
+
 type errHeadless struct {
-	error
 	ProjectURL string
 }
 
+func (e errHeadless) Error() string {
+	return "headless project"
+}
+
 func (r *Push) Run(params PushParams) (rerr error) {
 	defer rationalizeError(&rerr)
 
@@ -106,7 +112,7 @@ func (r *Push) Run(params PushParams) (rerr error) {
 	}
 
 	if r.project.IsHeadless() {
-		return &errHeadless{err, r.project.URL()}
+		return &errHeadless{r.project.URL()}
 	}
 
 	// Capture the primary intend of the user
@@ -154,7 +160,7 @@ func (r *Push) Run(params PushParams) (rerr error) {
 	var projectCreated bool
 	if intend&intendCreateProject > 0 || targetPjm == nil {
 		if targetPjm != nil {
-			return &errProjectNameInUse{errs.New("project name in use"), targetNamespace}
+			return &errProjectNameInUse{targetNamespace}
 		}
 
 		// If the user didn't necessarily intend to create the project we should ask them for confirmation

pkg/localcommit/localcommit.go

@@ -15,10 +15,13 @@ import (
 var proj *project.Project
 
 type ErrInvalidCommitID struct {
-	error
 	CommitID string
 }
 
+func (e ErrInvalidCommitID) Error() string {
+	return "invalid commit ID"
+}
+
 func setupProject(pjpath string) error {
 	if proj != nil && proj.Dir() == pjpath {
 		return nil
@@ -38,7 +41,7 @@ func Get(pjpath string) (strfmt.UUID, error) {
 
 	commitID := proj.LegacyCommitID()
 	if !strfmt.IsUUID(commitID) {
-		return "", &ErrInvalidCommitID{errs.New("Invalid commit ID"), commitID}
+		return "", &ErrInvalidCommitID{commitID}
 	}
 
 	return strfmt.UUID(commitID), nil