diff: support unified diff extension used by gofmt -d

diff/parse.go

@@ -11,14 +11,14 @@ import (
 )
 
 const (
-	tokenDiffGit        = "diff --git" // diff --git a/sample.old.txt b/sample.new.txt
-	tokenOldFile        = "---"        // --- sample.old.txt	2016-10-13 05:09:35.820791185 +0900
-	tokenNewFile        = "+++"        // +++ sample.new.txt	2016-10-13 05:15:26.839245048 +0900
-	tokenStartHunk      = "@@"         // @@ -1,3 +1,4 @@
-	tokenUnchangedLine  = " "          //  unchanged, contextual line
-	tokenAddedLine      = "+"          // +added line
-	tokenDeletedLine    = "-"          // -deleted line
-	tokenNoNewlineAtEOF = `\`          // \ No newline at end of file
+	tokenDiff           = "diff" // diff --git a/sample.old.txt b/sample.new.txt
+	tokenOldFile        = "---"  // --- sample.old.txt	2016-10-13 05:09:35.820791185 +0900
+	tokenNewFile        = "+++"  // +++ sample.new.txt	2016-10-13 05:15:26.839245048 +0900
+	tokenStartHunk      = "@@"   // @@ -1,3 +1,4 @@
+	tokenUnchangedLine  = " "    //  unchanged, contextual line
+	tokenAddedLine      = "+"    // +added line
+	tokenDeletedLine    = "-"    // -deleted line
+	tokenNoNewlineAtEOF = `\`    // \ No newline at end of file
 )
 
 var (
@@ -103,11 +103,11 @@ func (p *fileParser) parseHunks() ([]*Hunk, error) {
 		return nil, ErrNoHunks
 	}
 	if !bytes.HasPrefix(b, []byte(tokenStartHunk)) {
-		b, err := p.r.Peek(len(tokenDiffGit))
+		b, err := p.r.Peek(len(tokenDiff))
 		if err != nil {
 			return nil, ErrNoHunks
 		}
-		if bytes.HasPrefix(b, []byte(tokenDiffGit)) {
+		if bytes.HasPrefix(b, []byte(tokenDiff)) {
 			// git diff may contain a file diff with empty hunks.
 			// e.g. delete an empty file.
 			return []*Hunk{}, nil
@@ -211,17 +211,17 @@ LOOP:
 
 func parseExtendedHeader(r *bufio.Reader) []string {
 	var es []string
-	b, err := r.Peek(len(tokenDiffGit))
+	b, err := r.Peek(len(tokenDiff))
 	if err != nil {
 		return nil
 	}
-	// if starts with 'diff --git', parse extended header
-	if bytes.HasPrefix(b, []byte(tokenDiffGit)) {
+	// if starts with 'diff', parse extended header
+	if bytes.HasPrefix(b, []byte(tokenDiff)) {
 		diffgitline, _ := readline(r) // ignore err because we know it can read something
 		es = append(es, diffgitline)
 		for {
-			b, err := r.Peek(len(tokenDiffGit))
-			if err != nil || bytes.HasPrefix(b, []byte(tokenOldFile)) || bytes.HasPrefix(b, []byte(tokenDiffGit)) {
+			b, err := r.Peek(len(tokenDiff))
+			if err != nil || bytes.HasPrefix(b, []byte(tokenOldFile)) || bytes.HasPrefix(b, []byte(tokenDiff)) {
 				break
 			}
 			line, _ := readline(r)

diff/testdata/gen.sh

@@ -12,3 +12,4 @@ git diff --no-index golint.{old,new}.go > golint.diff
 git diff --no-index empty.txt /dev/null > newline_and_empty_deleted.diff
 git diff --no-index golint.{old,new}.go >> newline_and_empty_deleted.diff
 git -c core.quotepath=true diff --no-index 日本語.{old,new}.txt > 日本語.diff
+gofmt -d gofmt.go > gofmt.diff

diff/testdata/gofmt.diff

@@ -0,0 +1,27 @@
+diff -u gofmt.go.orig gofmt.go
+--- gofmt.go.orig	2020-07-26 08:01:09.260800318 +0000
++++ gofmt.go	2020-07-26 08:01:09.260800318 +0000
+@@ -1,6 +1,6 @@
+ package testdata
+
+-func    fmt     () {
++func fmt() {
+ 	// test
+ 	// test line
+ 	// test line
+@@ -10,11 +10,11 @@
+ 	// test line
+ 	// test line
+
+-println(
+-		"hello, gofmt test"    )
+-//comment
++	println(
++		"hello, gofmt test")
++	//comment
+ }
+
++type s struct{ A int }
+
+-type s struct { A int }
+ func (s s) String() { return "s" }

diff/testdata/gofmt.diff.json

@@ -0,0 +1,185 @@
+[
+  {
+    "PathOld": "gofmt.go.orig",
+    "PathNew": "gofmt.go",
+    "TimeOld": "2020-07-26 08:01:09.260800318 +0000",
+    "TimeNew": "2020-07-26 08:01:09.260800318 +0000",
+    "Hunks": [
+      {
+        "StartLineOld": 1,
+        "LineLengthOld": 6,
+        "StartLineNew": 1,
+        "LineLengthNew": 6,
+        "Section": "",
+        "Lines": [
+          {
+            "Type": 0,
+            "Content": "package testdata",
+            "LnumDiff": 1,
+            "LnumOld": 1,
+            "LnumNew": 1
+          },
+          {
+            "Type": 0,
+            "Content": "",
+            "LnumDiff": 2,
+            "LnumOld": 2,
+            "LnumNew": 2
+          },
+          {
+            "Type": 2,
+            "Content": "func    fmt     () {",
+            "LnumDiff": 3,
+            "LnumOld": 3,
+            "LnumNew": 0
+          },
+          {
+            "Type": 1,
+            "Content": "func fmt() {",
+            "LnumDiff": 4,
+            "LnumOld": 0,
+            "LnumNew": 3
+          },
+          {
+            "Type": 0,
+            "Content": "\t// test",
+            "LnumDiff": 5,
+            "LnumOld": 4,
+            "LnumNew": 4
+          },
+          {
+            "Type": 0,
+            "Content": "\t// test line",
+            "LnumDiff": 6,
+            "LnumOld": 5,
+            "LnumNew": 5
+          },
+          {
+            "Type": 0,
+            "Content": "\t// test line",
+            "LnumDiff": 7,
+            "LnumOld": 6,
+            "LnumNew": 6
+          }
+        ]
+      },
+      {
+        "StartLineOld": 10,
+        "LineLengthOld": 11,
+        "StartLineNew": 10,
+        "LineLengthNew": 11,
+        "Section": "",
+        "Lines": [
+          {
+            "Type": 0,
+            "Content": "\t// test line",
+            "LnumDiff": 9,
+            "LnumOld": 10,
+            "LnumNew": 10
+          },
+          {
+            "Type": 0,
+            "Content": "\t// test line",
+            "LnumDiff": 10,
+            "LnumOld": 11,
+            "LnumNew": 11
+          },
+          {
+            "Type": 0,
+            "Content": "",
+            "LnumDiff": 11,
+            "LnumOld": 12,
+            "LnumNew": 12
+          },
+          {
+            "Type": 2,
+            "Content": "println(",
+            "LnumDiff": 12,
+            "LnumOld": 13,
+            "LnumNew": 0
+          },
+          {
+            "Type": 2,
+            "Content": "\t\t\"hello, gofmt test\"    )",
+            "LnumDiff": 13,
+            "LnumOld": 14,
+            "LnumNew": 0
+          },
+          {
+            "Type": 2,
+            "Content": "//comment",
+            "LnumDiff": 14,
+            "LnumOld": 15,
+            "LnumNew": 0
+          },
+          {
+            "Type": 1,
+            "Content": "\tprintln(",
+            "LnumDiff": 15,
+            "LnumOld": 0,
+            "LnumNew": 13
+          },
+          {
+            "Type": 1,
+            "Content": "\t\t\"hello, gofmt test\")",
+            "LnumDiff": 16,
+            "LnumOld": 0,
+            "LnumNew": 14
+          },
+          {
+            "Type": 1,
+            "Content": "\t//comment",
+            "LnumDiff": 17,
+            "LnumOld": 0,
+            "LnumNew": 15
+          },
+          {
+            "Type": 0,
+            "Content": "}",
+            "LnumDiff": 18,
+            "LnumOld": 16,
+            "LnumNew": 16
+          },
+          {
+            "Type": 0,
+            "Content": "",
+            "LnumDiff": 19,
+            "LnumOld": 17,
+            "LnumNew": 17
+          },
+          {
+            "Type": 1,
+            "Content": "type s struct{ A int }",
+            "LnumDiff": 20,
+            "LnumOld": 0,
+            "LnumNew": 18
+          },
+          {
+            "Type": 0,
+            "Content": "",
+            "LnumDiff": 21,
+            "LnumOld": 18,
+            "LnumNew": 19
+          },
+          {
+            "Type": 2,
+            "Content": "type s struct { A int }",
+            "LnumDiff": 22,
+            "LnumOld": 19,
+            "LnumNew": 0
+          },
+          {
+            "Type": 0,
+            "Content": "func (s s) String() { return \"s\" }",
+            "LnumDiff": 23,
+            "LnumOld": 20,
+            "LnumNew": 20
+          }
+        ]
+      }
+    ],
+    "Extended": [
+      "diff -u gofmt.go.orig gofmt.go"
+    ]
+  }
+]

diff/testdata/gofmt.go

@@ -0,0 +1,20 @@
+package testdata
+
+func    fmt     () {
+	// test
+	// test line
+	// test line
+	// test line
+	// test line
+	// test line
+	// test line
+	// test line
+
+println(
+		"hello, gofmt test"    )
+//comment
+}
+
+
+type s struct { A int }
+func (s s) String() { return "s" }

diff/testdata/nonewline.diff

@@ -1,5 +1,5 @@
---- nonewline.old.txt	2016-10-13 15:34:14.931778318 +0900
-+++ nonewline.new.txt	2016-10-13 15:34:14.868444672 +0900
+--- nonewline.old.txt	2019-04-19 13:19:50.331526534 +0000
++++ nonewline.new.txt	2019-04-19 13:19:50.331526534 +0000
 @@ -1,4 +1,4 @@
  " vim: nofixeol noendofline
  No newline at end of both the old and new file

diff/testdata/nonewline.diff.json

@@ -2,8 +2,8 @@
   {
     "PathOld": "nonewline.old.txt",
     "PathNew": "nonewline.new.txt",
-    "TimeOld": "2016-10-13 15:34:14.931778318 +0900",
-    "TimeNew": "2016-10-13 15:34:14.868444672 +0900",
+    "TimeOld": "2019-04-19 13:19:50.331526534 +0000",
+    "TimeNew": "2019-04-19 13:19:50.331526534 +0000",
     "Hunks": [
       {
         "StartLineOld": 1,

diff/testdata/nonewline2.diff

@@ -1,5 +1,5 @@
---- nonewline2.old.txt	2016-10-13 15:34:15.141779355 +0900
-+++ nonewline2.new.txt	2016-10-13 15:34:15.075112360 +0900
+--- nonewline2.old.txt	2019-04-19 13:19:50.331526534 +0000
++++ nonewline2.new.txt	2019-04-19 13:19:50.331526534 +0000
 @@ -1,4 +1,4 @@
  No newline at end of both the old and new file (unchanged)
 -a

diff/testdata/nonewline2.diff.json

@@ -2,8 +2,8 @@
   {
     "PathOld": "nonewline2.old.txt",
     "PathNew": "nonewline2.new.txt",
-    "TimeOld": "2016-10-13 15:34:15.141779355 +0900",
-    "TimeNew": "2016-10-13 15:34:15.075112360 +0900",
+    "TimeOld": "2019-04-19 13:19:50.331526534 +0000",
+    "TimeNew": "2019-04-19 13:19:50.331526534 +0000",
     "Hunks": [
       {
         "StartLineOld": 1,

diff/testdata/nonewline3.diff

@@ -1,5 +1,5 @@
---- nonewline3.old.txt	2016-10-13 15:34:15.361780443 +0900
-+++ nonewline3.new.txt	2016-10-13 15:34:15.288446747 +0900
+--- nonewline3.old.txt	2019-04-19 13:19:50.331526534 +0000
++++ nonewline3.new.txt	2019-04-19 13:19:50.331526534 +0000
 @@ -1,6 +1,7 @@
  No newline at end of the old file
  Newline at end of the new file

diff/testdata/nonewline3.diff.json

@@ -2,8 +2,8 @@
   {
     "PathOld": "nonewline3.old.txt",
     "PathNew": "nonewline3.new.txt",
-    "TimeOld": "2016-10-13 15:34:15.361780443 +0900",
-    "TimeNew": "2016-10-13 15:34:15.288446747 +0900",
+    "TimeOld": "2019-04-19 13:19:50.331526534 +0000",
+    "TimeNew": "2019-04-19 13:19:50.331526534 +0000",
     "Hunks": [
       {
         "StartLineOld": 1,

diff/testdata/sample.diff

@@ -1,5 +1,5 @@
---- sample.old.txt	2016-10-13 05:09:35.820791185 +0900
-+++ sample.new.txt	2016-10-13 05:15:26.839245048 +0900
+--- sample.old.txt	2019-04-19 13:19:50.331526534 +0000
++++ sample.new.txt	2019-04-19 13:19:50.331526534 +0000
 @@ -1,3 +1,4 @@
  unchanged, contextual line
 -deleted line

diff/testdata/sample.diff.json

@@ -2,8 +2,8 @@
   {
     "PathOld": "sample.old.txt",
     "PathNew": "sample.new.txt",
-    "TimeOld": "2016-10-13 05:09:35.820791185 +0900",
-    "TimeNew": "2016-10-13 05:15:26.839245048 +0900",
+    "TimeOld": "2019-04-19 13:19:50.331526534 +0000",
+    "TimeNew": "2019-04-19 13:19:50.331526534 +0000",
     "Hunks": [
       {
         "StartLineOld": 1,