fix WriteContextDiff fmt.Sprintf format error

Author: visualfc

difflib/difflib.go

@@ -673,13 +673,17 @@ func WriteContextDiff(writer io.Writer, diff ContextDiff) error {
 	buf := bufio.NewWriter(writer)
 	defer buf.Flush()
 	var diffErr error
-	w := func(format string, args ...interface{}) {
+	wf := func(format string, args ...interface{}) {
 		_, err := buf.WriteString(fmt.Sprintf(format, args...))
 		if diffErr == nil && err != nil {
 			diffErr = err
 		}
 	}
-
+	ws := func(s string) error {
+		_, err := buf.WriteString(s)
+		return err
+	}
+	
 	if len(diff.Eol) == 0 {
 		diff.Eol = "\n"
 	}
@@ -704,39 +708,39 @@ func WriteContextDiff(writer io.Writer, diff ContextDiff) error {
 			if len(diff.ToDate) > 0 {
 				toDate = "\t" + diff.ToDate
 			}
-			w("*** %s%s%s", diff.FromFile, fromDate, diff.Eol)
-			w("--- %s%s%s", diff.ToFile, toDate, diff.Eol)
+			wf("*** %s%s%s", diff.FromFile, fromDate, diff.Eol)
+			wf("--- %s%s%s", diff.ToFile, toDate, diff.Eol)
 		}
 
 		first, last := g[0], g[len(g)-1]
-		w("***************" + diff.Eol)
+		wf("***************" + diff.Eol)
 
 		range1 := formatRangeContext(first.I1, last.I2)
-		w("*** %s ****%s", range1, diff.Eol)
+		wf("*** %s ****%s", range1, diff.Eol)
 		for _, c := range g {
 			if c.Tag == 'r' || c.Tag == 'd' {
 				for _, cc := range g {
 					if cc.Tag == 'i' {
 						continue
 					}
 					for _, line := range diff.A[cc.I1:cc.I2] {
-						w(prefix[cc.Tag] + line)
+						ws(prefix[cc.Tag] + line)
 					}
 				}
 				break
 			}
 		}
 
 		range2 := formatRangeContext(first.J1, last.J2)
-		w("--- %s ----%s", range2, diff.Eol)
+		wf("--- %s ----%s", range2, diff.Eol)
 		for _, c := range g {
 			if c.Tag == 'r' || c.Tag == 'i' {
 				for _, cc := range g {
 					if cc.Tag == 'd' {
 						continue
 					}
 					for _, line := range diff.B[cc.J1:cc.J2] {
-						w(prefix[cc.Tag] + line)
+						ws(prefix[cc.Tag] + line)
 					}
 				}
 				break

difflib/difflib_test.go

@@ -107,43 +107,7 @@ func ExampleGetUnifiedDiffCode() {
 two
 three
 four
-fmt.Printf("%s,%T",a,b)
-`
-	b := `zero
-one
-three
-four`
-	diff := UnifiedDiff{
-		A:        SplitLines(a),
-		B:        SplitLines(b),
-		FromFile: "Original",
-		FromDate: "2005-01-26 23:30:50",
-		ToFile:   "Current",
-		ToDate:   "2010-04-02 10:20:52",
-		Context:  3,
-	}
-	result, _ := GetUnifiedDiffString(diff)
-	fmt.Println(strings.Replace(result, "\t", " ", -1))
-	// Output:
-	// --- Original 2005-01-26 23:30:50
-	// +++ Current 2010-04-02 10:20:52
-	// @@ -1,6 +1,4 @@
-	// +zero
-	//  one
-	// -two
-	//  three
-	//  four
-	// -fmt.Printf("%s,%T",a,b)
-	// -
-}
-
-func ExampleGetUnifiedDiffString() {
-	a := `one
-two
-three
-four
-fmt.Printf("%s,%T",a,b)
-`
+fmt.Printf("%s,%T",a,b)`
 	b := `zero
 one
 three
@@ -162,21 +126,21 @@ four`
 	// Output:
 	// --- Original 2005-01-26 23:30:50
 	// +++ Current 2010-04-02 10:20:52
-	// @@ -1,6 +1,4 @@
+	// @@ -1,5 +1,4 @@
 	// +zero
 	//  one
 	// -two
 	//  three
 	//  four
 	// -fmt.Printf("%s,%T",a,b)
-	// -
 }
 
 func ExampleGetContextDiffCode() {
 	a := `one
 two
 three
-four`
+four
+fmt.Printf("%s,%T",a,b)`
 	b := `zero
 one
 tree
@@ -190,16 +154,17 @@ four`
 		Eol:      "\n",
 	}
 	result, _ := GetContextDiffString(diff)
-	fmt.Printf(strings.Replace(result, "\t", " ", -1))
+	fmt.Print(strings.Replace(result, "\t", " ", -1))
 	// Output:
 	// *** Original
 	// --- Current
 	// ***************
-	// *** 1,4 ****
+	// *** 1,5 ****
 	//   one
 	// ! two
 	// ! three
 	//   four
+	// - fmt.Printf("%s,%T",a,b)
 	// --- 1,4 ----
 	// + zero
 	//   one