fix: add fix for bufio, gzip, zlib NewWriterXxx changes.
Fixes #2979.
R=rsc, r
CC=golang-dev
https://golang.org/cl/5664046
diff --git a/doc/go1.html b/doc/go1.html
index 9b62d1a..a2cd045 100644
--- a/doc/go1.html
+++ b/doc/go1.html
@@ -578,7 +578,7 @@
<em>Updating</em>:
Code that uses packages in <code>exp</code> will need to be updated by hand,
or else compiled from an installation that has <code>exp</code> available.
-The go fix tool or the compiler will complain about such uses.
+The <code>go fix</code> tool or the compiler will complain about such uses.
</p>
<h3 id="old">The package tree old</h3>
@@ -603,7 +603,7 @@
<em>Updating</em>:
Code that uses packages now in <code>old</code> will need to be updated by hand,
or else compiled from an installation that has <code>old</code> available.
-The go fix tool will warn about such uses.
+The <code>go fix</code> tool will warn about such uses.
</p>
<h3 id="deleted">Deleted packages</h3>
@@ -863,8 +863,8 @@
</p>
<p>
-<i>Updating:</i> What little code is affected will be caught by the compiler
-and must be updated by hand. Such code is almost certainly incorrect.
+<em>Updating</em>:
+What little code is affected will be caught by the compiler and must be updated by hand.
</p>
<h3 id="bufio">The bufio package</h3>
@@ -879,7 +879,8 @@
<p>
<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
+Running <code>go fix</code> will update calls that assign the error to _.
+Calls that aren't fixed will be caught by the compiler and must be updated by hand.
</p>
<h3 id="bufio">The compress/flate, compress/gzip and compress/zlib packages</h3>
@@ -898,7 +899,8 @@
<p>
<em>Updating</em>
-What little code is affected will be caught by the compiler and must be updated by hand.
+Running <code>go fix</code> will update old names and calls that assign the error to _.
+Calls that aren't fixed will be caught by the compiler and must be updated by hand.
</p>
<h3 id="crypto_aes_des">The crypto/aes and crypto/des packages</h3>
@@ -1425,8 +1427,10 @@
The <a href="/pkg/os/#File.Fd"><code>Fd</code></a> method on files now
also returns a <code>uintptr</code>.</p>
-<p><em>Updating</em>: Code will fail to compile and must be updated
-by hand. </p>
+<p>
+<em>Updating</em>:
+What little code is affected will be caught by the compiler and must be updated by hand.
+</p>
<h4 id="os_fileinfo">The os.FileInfo type</h4>
@@ -1669,7 +1673,7 @@
<br>
§ <code>Atoi</code> persists but <code>Atoui</code> and <code>Atof32</code> do not, so
they may require
-a cast that must be added by hand; the go fix tool will warn about it.
+a cast that must be added by hand; the <code>go fix</code> tool will warn about it.
</p>
diff --git a/doc/go1.tmpl b/doc/go1.tmpl
index efe43bc..90bc9fc 100644
--- a/doc/go1.tmpl
+++ b/doc/go1.tmpl
@@ -502,7 +502,7 @@
<em>Updating</em>:
Code that uses packages in <code>exp</code> will need to be updated by hand,
or else compiled from an installation that has <code>exp</code> available.
-The go fix tool or the compiler will complain about such uses.
+The <code>go fix</code> tool or the compiler will complain about such uses.
</p>
<h3 id="old">The package tree old</h3>
@@ -527,7 +527,7 @@
<em>Updating</em>:
Code that uses packages now in <code>old</code> will need to be updated by hand,
or else compiled from an installation that has <code>old</code> available.
-The go fix tool will warn about such uses.
+The <code>go fix</code> tool will warn about such uses.
</p>
<h3 id="deleted">Deleted packages</h3>
@@ -767,8 +767,8 @@
</p>
<p>
-<i>Updating:</i> What little code is affected will be caught by the compiler
-and must be updated by hand. Such code is almost certainly incorrect.
+<em>Updating</em>:
+What little code is affected will be caught by the compiler and must be updated by hand.
</p>
<h3 id="bufio">The bufio package</h3>
@@ -783,7 +783,8 @@
<p>
<em>Updating</em>:
-What little code is affected will be caught by the compiler and must be updated by hand.
+Running <code>go fix</code> will update calls that assign the error to _.
+Calls that aren't fixed will be caught by the compiler and must be updated by hand.
</p>
<h3 id="bufio">The compress/flate, compress/gzip and compress/zlib packages</h3>
@@ -802,7 +803,8 @@
<p>
<em>Updating</em>
-What little code is affected will be caught by the compiler and must be updated by hand.
+Running <code>go fix</code> will update old names and calls that assign the error to _.
+Calls that aren't fixed will be caught by the compiler and must be updated by hand.
</p>
<h3 id="crypto_aes_des">The crypto/aes and crypto/des packages</h3>
@@ -1328,8 +1330,10 @@
The <a href="/pkg/os/#File.Fd"><code>Fd</code></a> method on files now
also returns a <code>uintptr</code>.</p>
-<p><em>Updating</em>: Code will fail to compile and must be updated
-by hand. </p>
+<p>
+<em>Updating</em>:
+What little code is affected will be caught by the compiler and must be updated by hand.
+</p>
<h4 id="os_fileinfo">The os.FileInfo type</h4>
@@ -1572,7 +1576,7 @@
<br>
§ <code>Atoi</code> persists but <code>Atoui</code> and <code>Atof32</code> do not, so
they may require
-a cast that must be added by hand; the go fix tool will warn about it.
+a cast that must be added by hand; the <code>go fix</code> tool will warn about it.
</p>
diff --git a/src/cmd/fix/newwriter.go b/src/cmd/fix/newwriter.go
new file mode 100644
index 0000000..4befe24
--- /dev/null
+++ b/src/cmd/fix/newwriter.go
@@ -0,0 +1,90 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+ "go/ast"
+)
+
+func init() {
+ register(newWriterFix)
+}
+
+var newWriterFix = fix{
+ "newWriter",
+ "2012-02-14",
+ newWriter,
+ `Adapt bufio, gzip and zlib NewWriterXxx calls for whether they return errors.
+
+Also rename gzip.Compressor and gzip.Decompressor to gzip.Writer and gzip.Reader.
+
+http://codereview.appspot.com/5639057 and
+http://codereview.appspot.com/5642054
+`,
+}
+
+func newWriter(f *ast.File) bool {
+ if !imports(f, "bufio") && !imports(f, "compress/gzip") && !imports(f, "compress/zlib") {
+ return false
+ }
+
+ fixed := false
+ walk(f, func(n interface{}) {
+ switch n := n.(type) {
+ case *ast.SelectorExpr:
+ if isTopName(n.X, "gzip") {
+ switch n.Sel.String() {
+ case "Compressor":
+ n.Sel = &ast.Ident{Name: "Writer"}
+ fixed = true
+ case "Decompressor":
+ n.Sel = &ast.Ident{Name: "Reader"}
+ fixed = true
+ }
+ } else if isTopName(n.X, "zlib") {
+ if n.Sel.String() == "NewWriterDict" {
+ n.Sel = &ast.Ident{Name: "NewWriterLevelDict"}
+ fixed = true
+ }
+ }
+
+ case *ast.AssignStmt:
+ // Drop the ", _" in assignments of the form:
+ // w0, _ = gzip.NewWriter(w1)
+ if len(n.Lhs) != 2 || len(n.Rhs) != 1 {
+ return
+ }
+ i, ok := n.Lhs[1].(*ast.Ident)
+ if !ok {
+ return
+ }
+ if i.String() != "_" {
+ return
+ }
+ c, ok := n.Rhs[0].(*ast.CallExpr)
+ if !ok {
+ return
+ }
+ s, ok := c.Fun.(*ast.SelectorExpr)
+ if !ok {
+ return
+ }
+ sel := s.Sel.String()
+ switch {
+ case isTopName(s.X, "bufio") && (sel == "NewReaderSize" || sel == "NewWriterSize"):
+ // No-op.
+ case isTopName(s.X, "gzip") && sel == "NewWriter":
+ // No-op.
+ case isTopName(s.X, "zlib") && sel == "NewWriter":
+ // No-op.
+ default:
+ return
+ }
+ n.Lhs = n.Lhs[:1]
+ fixed = true
+ }
+ })
+ return fixed
+}
diff --git a/src/cmd/fix/newwriter_test.go b/src/cmd/fix/newwriter_test.go
new file mode 100644
index 0000000..1f59628
--- /dev/null
+++ b/src/cmd/fix/newwriter_test.go
@@ -0,0 +1,83 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func init() {
+ addTestCases(newWriterTests, newWriter)
+}
+
+var newWriterTests = []testCase{
+ {
+ Name: "newWriter.0",
+ In: `package main
+
+import (
+ "bufio"
+ "compress/gzip"
+ "compress/zlib"
+ "io"
+
+ "foo"
+)
+
+func f() *gzip.Compressor {
+ var (
+ _ gzip.Compressor
+ _ *gzip.Decompressor
+ _ struct {
+ W *gzip.Compressor
+ R gzip.Decompressor
+ }
+ )
+
+ var w io.Writer
+ br := bufio.NewReader(nil)
+ br, _ = bufio.NewReaderSize(nil, 256)
+ bw, err := bufio.NewWriterSize(w, 256) // Unfixable, as it declares an err variable.
+ bw, _ = bufio.NewWriterSize(w, 256)
+ fw, _ := foo.NewWriter(w)
+ gw, _ := gzip.NewWriter(w)
+ gw, _ = gzip.NewWriter(w)
+ zw, _ := zlib.NewWriter(w)
+ _ = zlib.NewWriterDict(zw, 0, nil)
+ return gw
+}
+`,
+ Out: `package main
+
+import (
+ "bufio"
+ "compress/gzip"
+ "compress/zlib"
+ "io"
+
+ "foo"
+)
+
+func f() *gzip.Writer {
+ var (
+ _ gzip.Writer
+ _ *gzip.Reader
+ _ struct {
+ W *gzip.Writer
+ R gzip.Reader
+ }
+ )
+
+ var w io.Writer
+ br := bufio.NewReader(nil)
+ br = bufio.NewReaderSize(nil, 256)
+ bw, err := bufio.NewWriterSize(w, 256) // Unfixable, as it declares an err variable.
+ bw = bufio.NewWriterSize(w, 256)
+ fw, _ := foo.NewWriter(w)
+ gw := gzip.NewWriter(w)
+ gw = gzip.NewWriter(w)
+ zw := zlib.NewWriter(w)
+ _ = zlib.NewWriterLevelDict(zw, 0, nil)
+ return gw
+}
+`,
+ },
+}
