Add Join() from go1.20

.github/workflows/lint.yaml

@@ -0,0 +1,38 @@
+name: Lint
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+env:
+  SSH_AUTH_SOCK: /tmp/ssh_agent.sock
+  GOLANGCI_LINT_VERSION: v1.57.2
+
+jobs:
+  lint:
+    name: lint
+    strategy:
+      matrix:
+        os: [ ubuntu-latest ]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: ./go.mod
+          cache: true # caching and restoring go modules and build outputs
+
+      - name: Check that 'go mod tidy' was called before commit
+        run: go mod tidy && git diff --exit-code
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v4
+        with:
+          version: ${{ env.GOLANGCI_LINT_VERSION }}
+          skip-cache: true # cache/restore is done by actions/setup-go@v3 step
+          args: -v

.github/workflows/test.yaml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         go-version:
-          - 1.19.x
+          - 1.21.x
         os: [ ubuntu-latest ]
     runs-on: ${{ matrix.os }}
     steps:

.golangci.yml

@@ -0,0 +1,125 @@
+linters:
+  # Please, do not use `enable-all`: it's deprecated and will be removed soon.
+  # Inverted configuration with `enable-all` and `disable` is not scalable during updates of golangci-lint.
+  # Full list of linters - https://golangci-lint.run/usage/linters
+  disable-all: true
+  enable:
+    - bodyclose # https://github.com/timakin/bodyclose
+    - gomodguard
+    - errcheck # Mandatory. Do not disable.
+    - gocritic
+    - goimports
+    - gosec
+    - gosimple
+    - govet
+    - noctx
+    - nolintlint
+    - ineffassign # Mandatory. Do not disable.
+    - staticcheck # Mandatory. Do not disable.
+    - stylecheck
+    - typecheck
+    - unused
+
+# Other linters:
+#    - dogsled
+#    - dupl
+#    - exportloopref
+#    - exhaustive # e.g. missing cases in switch of type
+#    - funlen
+#    - gochecknoinits
+#    - gocognit
+#    - goconst
+#    - gocyclo
+#    - goerr113
+#    - gofmt
+#    - goprintffuncname
+#    - lll
+#    - misspell
+#    - nakedret
+#    - nlreturn
+#    - prealloc
+#    - revive
+#    - rowserrcheck
+#    - stylecheck
+#    - unconvert
+#    - unparam
+
+linters-settings:
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport # https://github.com/go-critic/go-critic/issues/845
+      - whyNoLint # checked by nolintlint linter
+      - hugeParam # TODO(vtopc): configure(80 bytes is probably not so much) and enable.
+      - rangeValCopy # TODO(vtopc): configure(disable for tests) and enable.
+      - appendAssign
+      - commentedOutCode
+
+  errcheck:
+    # List of functions to exclude from checking, where each entry is a single function to exclude.
+    # See https://github.com/kisielk/errcheck#excluding-functions for details.
+    exclude-functions:
+      - (io.Closer).Close
+      - (io.ReadCloser).Close
+
+  govet:
+    enable-all: true
+    disable:
+      - shadow
+      - fieldalignment
+
+  gomodguard:
+    blocked:
+      # List of blocked modules.
+      # Default: []
+      modules:
+        - github.com/golang/protobuf:
+            recommendations:
+              - google.golang.org/protobuf
+            reason: "see https://developers.google.com/protocol-buffers/docs/reference/go/faq#modules"
+        - github.com/pkg/errors:
+            recommendations:
+              - errors
+              - github.com/mailgun/errors
+            reason: "Deprecated"
+
+  stylecheck:
+    # https://staticcheck.io/docs/options#checks
+    checks: ["all"]
+
+issues:
+  # Maximum issues count per one linter. Set to 0 to disable. Default is 50.
+  max-issues-per-linter: 0
+
+  # Maximum count of issues with the same text. Set to 0 to disable. Default is 3.
+  max-same-issues: 50
+
+  exclude:
+    # Some packages have deprecated fields which continue to be useful
+    - SA1019
+
+  exclude-rules:
+    # Exclude some rules from tests.
+    - path: '_test\.go$'
+      linters:
+        - gosec
+        - noctx
+    - path: '_test\.go$'
+      text: "unnamedResult:"
+    - path: '.*mxresolv.*'
+      linters:
+        - gosec
+
+
+run:
+  # include test files or not, default is true
+  tests: true
+
+  # Timeout for analysis, e.g. 30s, 5m.
+  # Default: 1m
+  timeout: 5m

Makefile

@@ -0,0 +1,13 @@
+GOLANGCI_LINT = $(GOPATH)/bin/golangci-lint
+GOLANGCI_LINT_VERSION = v1.57.2
+
+.PHONY: lint
+lint: $(GOLANGCI_LINT)
+	$(GOLANGCI_LINT) run
+
+$(GOLANGCI_LINT):
+	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(GOPATH)/bin $(GOLANGCI_LINT_VERSION)
+
+.PHONY: test
+test:
+	go test -p 1 ./... -short -race -timeout 1m -count=1

errors.go

@@ -97,4 +97,16 @@ func Last(err error, target any) bool {
 	return false
 }
 
+// Join returns an error that wraps the given errors.
+// Any nil error values are discarded.
+// Join returns nil if every value in errs is nil.
+// The error formats as the concatenation of the strings obtained
+// by calling the Error method of each element of errs, with a newline
+// between each string.
+//
+// A non-nil error returned by Join implements the Unwrap() []error method.
+func Join(errs ...error) error {
+	return errors.Join(errs...)
+}
+
 var errorType = reflect.TypeOf((*error)(nil)).Elem()

fields.go

@@ -132,7 +132,7 @@ func (c *fields) Is(target error) bool {
 // cause of the issue. We only support this because some code
 // depends on github.com/pkg/errors.Cause() returning the cause
 // of the error.
-// deprecated use error.Is() or error.As() instead
+// Deprecated: use error.Is() or error.As() instead
 func (c *fields) Cause() error { return c.wrapped }
 
 func (c *fields) Error() string {

go.mod

@@ -1,6 +1,6 @@
 module github.com/mailgun/errors
 
-go 1.19
+go 1.21
 
 require (
 	github.com/ahmetb/go-linq v3.0.0+incompatible

stack.go

@@ -36,7 +36,7 @@ func (w *stack) Is(target error) bool {
 // cause of the issue. We only support this because some code
 // depends on github.com/pkg/errors.Cause() returning the cause
 // of the error.
-// deprecated use error.Is() or error.As() instead
+// Deprecated: use error.Is() or error.As() instead
 func (w *stack) Cause() error { return w.error }
 
 func (w *stack) HasFields() map[string]any {

stack_test.go

@@ -136,7 +136,7 @@ func TestFormatStack(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.Name, func(t *testing.T) {
 			out := fmt.Sprintf(tt.format, tt.err)
-			//t.Log(out)
+			// t.Log(out)
 
 			for _, line := range tt.want {
 				assert.Contains(t, out, line)

wrap.go

@@ -62,7 +62,7 @@ func (e *wrappedError) Is(target error) bool {
 // cause of the issue. We only support this because some code
 // depends on github.com/pkg/errors.Cause() returning the cause
 // of the error.
-// deprecated use error.Is() or error.As() instead
+// Deprecated: use error.Is() or error.As() instead
 func (e *wrappedError) Cause() error { return e.wrapped }
 
 func (e *wrappedError) Error() string {