feat(errors): extract pkg/errors stacktraces

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## TBD
 
+### Enhancements
+
+* Extract stacktrace contents on errors wrapped by
+ [`pkg/errors`](https://github.com/pkg/errors).
+
 ### Bug fixes
 
 * Send web framework name with severity reason if set. Previously this value was

errors/error.go

@@ -4,6 +4,7 @@ package errors
 import (
  "bytes"
  "fmt"
+ "github.com/pkg/errors"
  "reflect"
  "runtime"
 )
@@ -33,6 +34,11 @@ type ErrorWithStackFrames interface {
  StackFrames() []StackFrame
 }
 
+type errorWithStack interface {
+ StackTrace() errors.StackTrace
+ Error() string
+}
+
 // New makes an Error from the given value. If that value is already an
 // error then it will be used directly, if not, it will be passed to
 // fmt.Errorf("%v"). The skip parameter indicates how far up the stack
@@ -48,6 +54,16 @@ func New(e interface{}, skip int) *Error {
  Err: e,
  stack: e.Callers(),
  }
+ case errorWithStack:
+ trace := e.StackTrace()
+ stack := make([]uintptr, len(trace))
+ for i, ptr := range trace {
+ stack[i] = uintptr(ptr) - 1
+ }
+ return &Error{
+ Err: e,
+ stack: stack,
+ }
  case ErrorWithStackFrames:
  stack := make([]uintptr, len(e.StackFrames()))
  for i, frame := range e.StackFrames() {

errors/error_test.go

@@ -4,8 +4,11 @@ import (
  "bytes"
  "fmt"
  "io"
+ "runtime"
  "strings"
  "testing"
+
+ "github.com/pkg/errors"
 )
 
 // fixture functions doing work to avoid inlining
@@ -44,7 +47,7 @@ func TestParsePanicStack(t *testing.T) {
  }
  expected := []StackFrame{
  StackFrame{Name: "TestParsePanicStack.func1", File: "errors/error_test.go"},
- StackFrame{Name: "a", File: "errors/error_test.go", LineNumber: 13},
+ StackFrame{Name: "a", File: "errors/error_test.go", LineNumber: 16},
  }
  assertStacksMatch(t, expected, err.StackFrames())
  }()
@@ -88,7 +91,7 @@ func TestSkipWorks(t *testing.T) {
  }
 
  expected := []StackFrame{
- StackFrame{Name: "a", File: "errors/error_test.go", LineNumber: 13},
+ StackFrame{Name: "a", File: "errors/error_test.go", LineNumber: 16},
  }
 
  assertStacksMatch(t, expected, err.StackFrames())
@@ -182,6 +185,26 @@ func TestNewError(t *testing.T) {
  }
 }
 
+func TestUnwrapPkgError(t *testing.T) {
+ _, _, line, ok := runtime.Caller(0) // grab line immediately before error generator
+ top := func() error {
+ err := fmt.Errorf("OH NO")
+ return errors.Wrap(err, "failed") // the correct line for the top of the stack
+ }
+ unwrapped := New(top(), 0) // if errors.StackTrace detection fails, this line will be top of stack
+ if !ok {
+ t.Fatalf("Something has gone wrong with loading the current stack")
+ }
+ if unwrapped.Error() != "failed: OH NO" {
+ t.Errorf("Failed to unwrap error: %s", unwrapped.Error())
+ }
+ expected := []StackFrame{
+ StackFrame{Name: "TestUnwrapPkgError.func1", File: "errors/error_test.go", LineNumber: line + 3},
+ StackFrame{Name: "TestUnwrapPkgError", File: "errors/error_test.go", LineNumber: line + 5},
+ }
+ assertStacksMatch(t, expected, unwrapped.StackFrames())
+}
+
 func ExampleErrorf() {
  for i := 1; i <= 2; i++ {
  if i%2 == 1 {