gofix: be more conservative about rewrite to os.Create

Rewrite only if we understood all the flags we saw.

R=r
CC=golang-dev
https://golang.org/cl/4376046

diff --git a/src/cmd/gofix/osopen.go b/src/cmd/gofix/osopen.go
index 5d7f5cbde54f20e26c4b5333599408d91494536a..49993d8f99877729fcc9af3c4a724476e9749355 100644 (file)
--- a/src/cmd/gofix/osopen.go
+++ b/src/cmd/gofix/osopen.go
@@ -70,7 +70,6 @@ func osopen(f *ast.File) bool {
 func isCreateFlag(flag ast.Expr) bool {
        foundCreate := false
        foundTrunc := false
-       foundAppend := false
        // OR'ing of flags: is O_CREATE on?  + or | would be fine; we just look for os.O_CREATE
        // and don't worry about the actual opeator.
        p := flag.Pos()
@@ -80,14 +79,21 @@ func isCreateFlag(flag ast.Expr) bool {
                if isBinary {
                        lhs = expr.Y
                }
-               if isPkgDot(lhs, "os", "O_CREATE") {
-                       foundCreate = true
+               sel, ok := lhs.(*ast.SelectorExpr)
+               if !ok || !isTopName(sel.X, "os") {
+                       return false
                }
-               if isPkgDot(lhs, "os", "O_TRUNC") {
+               switch sel.Sel.Name {
+               case "O_CREATE":
+                       foundCreate = true
+               case "O_TRUNC":
                        foundTrunc = true
-               }
-               if isPkgDot(lhs, "os", "O_APPEND") {
-                       foundAppend = true
+               case "O_RDONLY", "O_WRONLY", "O_RDWR":
+                       // okay 
+               default:
+                       // Unexpected flag, like O_APPEND or O_EXCL.
+                       // Be conservative and do not rewrite.
+                       return false
                }
                if !isBinary {
                        break
@@ -97,9 +103,6 @@ func isCreateFlag(flag ast.Expr) bool {
        if !foundCreate {
                return false
        }
-       if foundAppend {
-               return false
-       }
        if !foundTrunc {
                warn(p, "rewrote os.Open with O_CREATE but not O_TRUNC to os.Create")
        }

diff --git a/src/cmd/gofix/osopen_test.go b/src/cmd/gofix/osopen_test.go
index b0a4f63c6939f584decbede81418eeaac06898ce..43ddd1a40da9b190d7aae2c372ad38a6eb7bc37e 100644 (file)
--- a/src/cmd/gofix/osopen_test.go
+++ b/src/cmd/gofix/osopen_test.go
@@ -28,6 +28,8 @@ func f() {
        os.Open(a, os.O_CREATE|os.O_TRUNC, 0664)
        os.Open(a, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
        os.Open(a, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
+       os.Open(a, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
+       os.Open(a, os.O_SURPRISE|os.O_CREATE, 0666)
        _ = os.O_CREAT
 }
 `,
@@ -48,6 +50,8 @@ func f() {
        os.Create(a)
        os.Create(a)
        os.OpenFile(a, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
+       os.OpenFile(a, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
+       os.OpenFile(a, os.O_SURPRISE|os.O_CREATE, 0666)
        _ = os.O_CREATE
 }
 `,