status: return slice of error from collectConstraints()

Errors from collectConstraints() should not result in failure of status.
These errors are logged to stderr and the error count is added to
`errCount` of `runStatusAll()`. This results in letting the user know
about incomplete status result, keeping the status output clean. Running
status in verbose mode would show all those errors.

Author: darkowlzz

cmd/dep/status.go

@@ -417,7 +417,12 @@ func runStatusAll(ctx *dep.Ctx, out outputter, p *dep.Project, sm gps.SourceMana
 		return false, 0, errors.Wrapf(err, "could not set up solver for input hashing")
 	}
 
-	cm := collectConstraints(ctx, p, sm)
+	// Errors while collecting constraints should not fail the whole status run.
+	// It should count the error and tell the user about incomplete results.
+	cm, ccerrs := collectConstraints(ctx, p, sm)
+	if len(ccerrs) > 0 {
+		errCount += len(ccerrs)
+	}
 
 	// Get the project list and sort it so that the printed output users see is
 	// deterministically ordered. (This may be superfluous if the lock is always
@@ -566,7 +571,7 @@ func runStatusAll(ctx *dep.Ctx, out outputter, p *dep.Project, sm gps.SourceMana
 
 			// Count ListVersions error because we get partial results when
 			// this happens.
-			errCount = len(errListVerCh)
+			errCount += len(errListVerCh)
 			if ctx.Verbose {
 				for err := range errListVerCh {
 					ctx.Err.Println(err.Error())
@@ -684,28 +689,31 @@ type projectConstraint struct {
 type constraintsCollection map[string][]projectConstraint
 
 // collectConstraints collects constraints declared by all the dependencies.
-func collectConstraints(ctx *dep.Ctx, p *dep.Project, sm gps.SourceManager) constraintsCollection {
+// It returns constraintsCollection and a slice of errors encountered while
+// collecting the constraints, if any.
+func collectConstraints(ctx *dep.Ctx, p *dep.Project, sm gps.SourceManager) (constraintsCollection, []error) {
 	logger := ctx.Err
 	if !ctx.Verbose {
 		logger = log.New(ioutil.Discard, "", 0)
 	}
 
 	logger.Println("Collecting project constraints:")
 
+	var mutex sync.Mutex
+	constraintCollection := make(constraintsCollection)
+
 	// Get direct deps of the root project.
 	_, directDeps, err := getDirectDependencies(sm, p)
 	if err != nil {
-		logger.Println("Error getting direct deps:", err)
+		// Return empty collection, not nil, if we fail here.
+		return constraintCollection, []error{errors.Wrap(err, "failed to get direct dependencies")}
 	}
 
 	// Create a root analyzer.
 	rootAnalyzer := newRootAnalyzer(true, ctx, directDeps, sm)
 
 	lp := p.Lock.Projects()
 
-	var mutex sync.Mutex
-	constraintCollection := make(constraintsCollection)
-
 	// Channel for receiving all the errors.
 	errCh := make(chan error, len(lp))
 
@@ -750,13 +758,15 @@ func collectConstraints(ctx *dep.Ctx, p *dep.Project, sm gps.SourceManager) cons
 	wg.Wait()
 	close(errCh)
 
+	var errs []error
 	if len(errCh) > 0 {
-		for err := range errCh {
-			logger.Println(err.Error())
+		for e := range errCh {
+			errs = append(errs, e)
+			logger.Println(e.Error())
 		}
 	}
 
-	return constraintCollection
+	return constraintCollection, errs
 }
 
 type byProject []projectConstraint

cmd/dep/status_test.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"io/ioutil"
 	"log"
+	"path/filepath"
 	"reflect"
 	"testing"
 	"text/tabwriter"
@@ -299,45 +300,42 @@ func TestCollectConstraints(t *testing.T) {
 
 	cases := []struct {
 		name            string
-		project         dep.Project
+		lock            dep.Lock
 		wantConstraints constraintsCollection
+		wantErr         bool
 	}{
 		{
 			name: "without any constraints",
-			project: dep.Project{
-				Lock: &dep.Lock{
-					P: []gps.LockedProject{
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/sdboyer/deptest")},
-							gps.NewVersion("v1.0.0"),
-							[]string{"."},
-						),
-					},
+			lock: dep.Lock{
+				P: []gps.LockedProject{
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/sdboyer/deptest")},
+						gps.NewVersion("v1.0.0"),
+						[]string{"."},
+					),
 				},
 			},
 			wantConstraints: constraintsCollection{},
 		},
 		{
 			name: "with multiple constraints",
-			project: dep.Project{
-				Lock: &dep.Lock{
-					P: []gps.LockedProject{
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/sdboyer/deptest")},
-							gps.NewVersion("v1.0.0"),
-							[]string{"."},
-						),
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-1")},
-							gps.NewVersion("v0.1.0"),
-							[]string{"."},
-						),
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-2")},
-							gps.NewBranch("master").Pair(gps.Revision("824a8d56a4c6b2f4718824a98cd6d70d3dbd4c3e")),
-							[]string{"."},
-						),
-					},
+			lock: dep.Lock{
+				P: []gps.LockedProject{
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/sdboyer/deptest")},
+						gps.NewVersion("v1.0.0"),
+						[]string{"."},
+					),
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-1")},
+						gps.NewVersion("v0.1.0"),
+						[]string{"."},
+					),
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-2")},
+						gps.NewBranch("master").Pair(gps.Revision("824a8d56a4c6b2f4718824a98cd6d70d3dbd4c3e")),
+						[]string{"."},
+					),
 				},
 			},
 			wantConstraints: constraintsCollection{
@@ -355,27 +353,26 @@ func TestCollectConstraints(t *testing.T) {
 		},
 		{
 			name: "skip projects with invalid versions",
-			project: dep.Project{
-				Lock: &dep.Lock{
-					P: []gps.LockedProject{
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-1")},
-							gps.NewVersion("v0.1.0"),
-							[]string{"."},
-						),
-						gps.NewLockedProject(
-							gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-2")},
-							gps.NewVersion("v1.0.0"),
-							[]string{"."},
-						),
-					},
+			lock: dep.Lock{
+				P: []gps.LockedProject{
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-1")},
+						gps.NewVersion("v0.1.0"),
+						[]string{"."},
+					),
+					gps.NewLockedProject(
+						gps.ProjectIdentifier{ProjectRoot: gps.ProjectRoot("github.com/darkowlzz/deptest-project-2")},
+						gps.NewVersion("v1.0.0"),
+						[]string{"."},
+					),
 				},
 			},
 			wantConstraints: constraintsCollection{
 				"github.com/sdboyer/deptest": []projectConstraint{
 					{"github.com/darkowlzz/deptest-project-1", ver1},
 				},
 			},
+			wantErr: true,
 		},
 	}
 
@@ -396,12 +393,23 @@ func TestCollectConstraints(t *testing.T) {
 	h.Must(err)
 	defer sm.Release()
 
+	// Create new project and set root. Setting root is required for PackageList
+	// to run properly.
+	p := new(dep.Project)
+	p.SetRoot(filepath.Join(pwd, "src"))
+
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			gotConstraints := collectConstraints(ctx, &c.project, sm)
+			p.Lock = &c.lock
+			gotConstraints, err := collectConstraints(ctx, p, sm)
+			if len(err) > 0 && !c.wantErr {
+				t.Fatalf("unexpected errors while collecting constraints: %v", err)
+			} else if len(err) == 0 && c.wantErr {
+				t.Fatalf("expected errors while collecting constraints, but got none")
+			}
 
 			if !reflect.DeepEqual(gotConstraints, c.wantConstraints) {
-				t.Fatalf("Unexpected collected constraints: \n\t(GOT): %v\n\t(WNT): %v", gotConstraints, c.wantConstraints)
+				t.Fatalf("unexpected collected constraints: \n\t(GOT): %v\n\t(WNT): %v", gotConstraints, c.wantConstraints)
 			}
 		})
 	}