fix: error extractor

Author: ldez

pkg/goanalysis/pkgerrors/extract.go

@@ -19,13 +19,16 @@ func extractErrors(pkg *packages.Package) []packages.Error {
 	}
 
 	seenErrors := map[string]bool{}
+
 	var uniqErrors []packages.Error
 	for _, err := range errors {
 		msg := stackCrusher(err.Error())
 		if seenErrors[msg] {
 			continue
 		}
 
+		// Important to avoid duplicate errors:
+		// the goal is to keep the most relevant error.
 		if msg != err.Error() {
 			continue
 		}
@@ -35,6 +38,20 @@ func extractErrors(pkg *packages.Package) []packages.Error {
 		uniqErrors = append(uniqErrors, err)
 	}
 
+	// In some cases, the error stack doesn't contain the tip error.
+	// We must keep the original error.
+	if len(uniqErrors) == 0 {
+		for _, err := range errors {
+			if seenErrors[err.Error()] {
+				continue
+			}
+
+			seenErrors[err.Error()] = true
+
+			uniqErrors = append(uniqErrors, err)
+		}
+	}
+
 	if len(pkg.GoFiles) != 0 {
 		// errors were extracted from deps and have at least one file in package
 		for i := range uniqErrors {

pkg/goanalysis/pkgerrors/extract_test.go

@@ -4,8 +4,102 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"golang.org/x/tools/go/packages"
 )
 
+func Test_extractErrors(t *testing.T) {
+	testCases := []struct {
+		desc string
+		pkg  *packages.Package
+
+		expected []packages.Error
+	}{
+		{
+			desc: "package with errors",
+			pkg: &packages.Package{
+				IllTyped: true,
+				Errors: []packages.Error{
+					{Pos: "/home/ldez/sources/golangci/sandbox/main.go:6:11", Msg: "test"},
+				},
+			},
+			expected: []packages.Error{
+				{Pos: "/home/ldez/sources/golangci/sandbox/main.go:6:11", Msg: "test"},
+			},
+		},
+		{
+			desc: "full error stack deduplication",
+			pkg: &packages.Package{
+				IllTyped: true,
+				Imports: map[string]*packages.Package{
+					"test": {
+						IllTyped: true,
+						Errors: []packages.Error{
+							{
+								Pos:  "/home/ldez/sources/golangci/sandbox/main.go:6:11",
+								Msg:  `/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/result/processors/nolint.go:13:2: /home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/result/processors/nolint.go:13:2: could not import github.com/golangci/golangci-lint/pkg/lint/lintersdb (/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/lint/lintersdb/manager.go:13:2: could not import github.com/golangci/golangci-lint/pkg/golinters (/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/golinters/deadcode.go:21:9: undeclared name: linterName))`,
+								Kind: 3,
+							},
+							{
+								Pos:  "/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/result/processors/nolint.go:13:2",
+								Msg:  `could not import github.com/golangci/golangci-lint/pkg/lint/lintersdb (/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/lint/lintersdb/manager.go:13:2: could not import github.com/golangci/golangci-lint/pkg/golinters (/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/golinters/deadcode.go:21:9: undeclared name: linterName))`,
+								Kind: 3,
+							},
+							{
+								Pos:  "/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/lint/lintersdb/manager.go:13:2",
+								Msg:  `could not import github.com/golangci/golangci-lint/pkg/golinters (/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/golinters/deadcode.go:21:9: undeclared name: linterName)`,
+								Kind: 3,
+							},
+							{
+								Pos:  "/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/golinters/deadcode.go:21:9:",
+								Msg:  `undeclared name: linterName)`,
+								Kind: 3,
+							},
+						},
+					},
+				},
+			},
+			expected: []packages.Error{{
+				Pos:  "/home/ldez/sources/go/src/github.com/golangci/golangci-lint/pkg/golinters/deadcode.go:21:9:",
+				Msg:  "undeclared name: linterName)",
+				Kind: 3,
+			}},
+		},
+		{
+			desc: "package with import errors but with only one error and without tip error",
+			pkg: &packages.Package{
+				IllTyped: true,
+				Imports: map[string]*packages.Package{
+					"test": {
+						IllTyped: true,
+						Errors: []packages.Error{
+							{
+								Pos:  "/home/ldez/sources/golangci/sandbox/main.go:6:11",
+								Msg:  "could not import github.com/example/foo (main.go:6:2: missing go.sum entry for module providing package github.com/example/foo (imported by github.com/golangci/sandbox); to add:\n\tgo get github.com/golangci/sandbox)",
+								Kind: 3,
+							},
+						},
+					},
+				},
+			},
+			expected: []packages.Error{{
+				Pos:  "/home/ldez/sources/golangci/sandbox/main.go:6:11",
+				Msg:  "could not import github.com/example/foo (main.go:6:2: missing go.sum entry for module providing package github.com/example/foo (imported by github.com/golangci/sandbox); to add:\n\tgo get github.com/golangci/sandbox)",
+				Kind: 3,
+			}},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			errors := extractErrors(test.pkg)
+
+			assert.Equal(t, test.expected, errors)
+		})
+	}
+}
+
 func Test_stackCrusher(t *testing.T) {
 	testCases := []struct {
 		desc     string