cmd/doc: show the package clause always

If no writes to the package buffer happen, then the package clause
does not get printed. This is a bug for cases where a file just contains
the package clause.

We fix this by separating the printing of package clause to a new
function and calling it from (*pkgBuffer).Write as well as (*Package).flush.

Updates #31457

Change-Id: Ia3bd0ea3963274c460a45d1e37fafc6ee0a197f0
Reviewed-on: https://go-review.googlesource.com/c/go/+/206128
Run-TryBot: Agniva De Sarker <agniva.quicksilver@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

diff --git a/src/cmd/doc/doc_test.go b/src/cmd/doc/doc_test.go
index e425045ba5cebd30382844cacf14cd201b6c47e5..c0959acca130693d86fd3cae2f46fd57f00da337 100644 (file)
--- a/src/cmd/doc/doc_test.go
+++ b/src/cmd/doc/doc_test.go
@@ -211,6 +211,13 @@ var tests = []test{
                        `func \(unexportedType\)`,
                },
        },
+       // Package with just the package declaration. Issue 31457.
+       {
+               "only package declaration",
+               []string{"-all", p + "/nested/empty"},
+               []string{`package empty .*import`},
+               nil,
+       },
        // Package dump -short
        {
                "full package with -short",

diff --git a/src/cmd/doc/pkg.go b/src/cmd/doc/pkg.go
index bfbe765d3206f91287a2fe2471cc2468b175e5fa..7b8bd1aeb4a2c1cd48328326f5c543a03320e90c 100644 (file)
--- a/src/cmd/doc/pkg.go
+++ b/src/cmd/doc/pkg.go
@@ -53,14 +53,18 @@ type pkgBuffer struct {
 }
 
 func (pb *pkgBuffer) Write(p []byte) (int, error) {
-       if !pb.printed && len(p) > 0 {
+       pb.packageClause()
+       return pb.Buffer.Write(p)
+}
+
+func (pb *pkgBuffer) packageClause() {
+       if !pb.printed {
                pb.printed = true
                // Only show package clause for commands if requested explicitly.
                if pb.pkg.pkg.Name != "main" || showCmd {
                        pb.pkg.packageClause()
                }
        }
-       return pb.Buffer.Write(p)
 }
 
 type PackageError string // type returned by pkg.Fatalf.
@@ -210,6 +214,8 @@ func (pkg *Package) Printf(format string, args ...interface{}) {
 }
 
 func (pkg *Package) flush() {
+       // Print the package clause in case it wasn't written already.
+       pkg.buf.packageClause()
        _, err := pkg.writer.Write(pkg.buf.Bytes())
        if err != nil {
                log.Fatal(err)

diff --git a/src/cmd/doc/testdata/nested/empty/empty.go b/src/cmd/doc/testdata/nested/empty/empty.go
new file mode 100644 (file)
index 0000000..609cf0e
--- /dev/null
+++ b/src/cmd/doc/testdata/nested/empty/empty.go
@@ -0,0 +1 @@
+package empty