remove repeated error stack file lines among stacks for package gerror (#2199)

* remove repeated error stack file lines among stacks for package gerror

* fix nil pointer error for package gerror

errors/gerror/gerror_error_stack.go

@@ -8,29 +8,53 @@ package gerror
 
 import (
 	"bytes"
+	"container/list"
 	"fmt"
+	"runtime"
+	"strings"
+
+	"github.com/gogf/gf/v2/internal/consts"
 )
 
-// Stack returns the stack callers as string.
-// It returns an empty string if the `err` does not support stacks.
+// stackInfo manages stack info of certain error.
+type stackInfo struct {
+	Index   int        // Index is the index of current error in whole error stacks.
+	Message string     // Error information string.
+	Lines   *list.List // Lines contains all error stack lines of current error stack in sequence.
+}
+
+// stackLine manages each line info of stack.
+type stackLine struct {
+	Function string // Function name, which contains its full package path.
+	FileLine string // FileLine is the source file name and its line number of Function.
+}
+
+// Stack returns the error stack information as string.
 func (err *Error) Stack() string {
 	if err == nil {
 		return ""
 	}
 	var (
-		loop   = err
-		index  = 1
-		buffer = bytes.NewBuffer(nil)
+		loop  = err
+		index = 1
+		infos []*stackInfo
 	)
 	for loop != nil {
-		buffer.WriteString(fmt.Sprintf("%d. %-v\n", index, loop))
+		info := &stackInfo{
+			Index:   index,
+			Message: fmt.Sprintf("%-v", loop),
+		}
 		index++
-		formatSubStack(loop.stack, buffer)
+		infos = append(infos, info)
+		loopLinesOfStackInfo(loop.stack, info)
 		if loop.error != nil {
 			if e, ok := loop.error.(*Error); ok {
 				loop = e
 			} else {
-				buffer.WriteString(fmt.Sprintf("%d. %s\n", index, loop.error.Error()))
+				infos = append(infos, &stackInfo{
+					Index:   index,
+					Message: loop.error.Error(),
+				})
 				index++
 				break
 			}
@@ -38,5 +62,110 @@ func (err *Error) Stack() string {
 			break
 		}
 	}
+	filterLinesOfStackInfos(infos)
+	return formatStackInfos(infos)
+}
+
+// filterLinesOfStackInfos removes repeated lines, which exist in subsequent stacks, from top errors.
+func filterLinesOfStackInfos(infos []*stackInfo) {
+	var (
+		ok      bool
+		set     = make(map[string]struct{})
+		info    *stackInfo
+		line    *stackLine
+		removes []*list.Element
+	)
+	for i := len(infos) - 1; i >= 0; i-- {
+		info = infos[i]
+		if info.Lines == nil {
+			continue
+		}
+		for n, e := 0, info.Lines.Front(); n < info.Lines.Len(); n, e = n+1, e.Next() {
+			line = e.Value.(*stackLine)
+			if _, ok = set[line.FileLine]; ok {
+				removes = append(removes, e)
+			} else {
+				set[line.FileLine] = struct{}{}
+			}
+		}
+		if len(removes) > 0 {
+			for _, e := range removes {
+				info.Lines.Remove(e)
+			}
+		}
+		removes = removes[:0]
+	}
+}
+
+// formatStackInfos formats and returns error stack information as string.
+func formatStackInfos(infos []*stackInfo) string {
+	var buffer = bytes.NewBuffer(nil)
+	for i, info := range infos {
+		buffer.WriteString(fmt.Sprintf("%d. %s\n", i+1, info.Message))
+		if info.Lines != nil && info.Lines.Len() > 0 {
+			formatStackLines(buffer, info.Lines)
+		}
+	}
 	return buffer.String()
 }
+
+// formatStackLines formats and returns error stack lines as string.
+func formatStackLines(buffer *bytes.Buffer, lines *list.List) string {
+	var (
+		line   *stackLine
+		space  = "  "
+		length = lines.Len()
+	)
+	for i, e := 0, lines.Front(); i < length; i, e = i+1, e.Next() {
+		line = e.Value.(*stackLine)
+		// Graceful indent.
+		if i >= 9 {
+			space = " "
+		}
+		buffer.WriteString(fmt.Sprintf(
+			"   %d).%s%s\n        %s\n",
+			i+1, space, line.Function, line.FileLine,
+		))
+	}
+	return buffer.String()
+}
+
+// loopLinesOfStackInfo iterates the stack info lines and produces the stack line info.
+func loopLinesOfStackInfo(st stack, info *stackInfo) {
+	if st == nil {
+		return
+	}
+	for _, p := range st {
+		if fn := runtime.FuncForPC(p - 1); fn != nil {
+			file, line := fn.FileLine(p - 1)
+			if isUsingBriefStack {
+				// filter whole GoFrame packages stack paths.
+				if strings.Contains(file, consts.StackFilterKeyForGoFrame) {
+					continue
+				}
+			} else {
+				// package path stack filtering.
+				if strings.Contains(file, stackFilterKeyLocal) {
+					continue
+				}
+			}
+			// Avoid stack string like "`autogenerated`"
+			if strings.Contains(file, "<") {
+				continue
+			}
+			// Ignore GO ROOT paths.
+			if goRootForFilter != "" &&
+				len(file) >= len(goRootForFilter) &&
+				file[0:len(goRootForFilter)] == goRootForFilter {
+				continue
+			}
+			if info.Lines == nil {
+				info.Lines = list.New()
+			}
+			info.Lines.PushBack(&stackLine{
+				Function: fn.Name(),
+				FileLine: fmt.Sprintf(`%s:%d`, file, line),
+			})
+		}
+	}
+}