Source files: fix empty line in Package-List

deb/format.go

@@ -288,8 +288,11 @@ func (c *ControlFileReader) ReadStanza() (Stanza, error) {
 			lastField = canonicalCase(parts[0])
 			lastFieldMultiline = isMultilineField(lastField, c.isRelease)
 			if lastFieldMultiline {
-				stanza[lastField] = parts[1]
-				if parts[1] != "" {
+				// Trim trailing whitespace from the inline value so that
+				// "Package-List: " does not add empty line
+				inlineVal := strings.TrimRight(parts[1], " \t")
+				stanza[lastField] = inlineVal
+				if inlineVal != "" {
 					stanza[lastField] += "\n"
 				}
 			} else {

deb/format_test.go

@@ -128,6 +128,35 @@ func (s *ControlFileSuite) TestReadWriteStanza(c *C) {
 	c.Assert(strings.HasPrefix(str, "Package: "), Equals, true)
 }
 
+// Sources may contain "Package-List: " with a trailing space.
+// That trailing space must not be preserved and re-emitted
+// as a spurious blank continuation line when the stanza is written back out.
+func (s *ControlFileSuite) TestPackageListTrailingSpace(c *C) {
+	input := "Package-List: \n" +
+		" bash deb shells required arch=any\n" +
+		" bash-doc deb doc optional arch=all\n"
+
+	r := NewControlFileReader(bytes.NewBufferString(input), false, false)
+	stanza, err := r.ReadStanza()
+	c.Assert(err, IsNil)
+
+	c.Check(stanza["Package-List"], Equals,
+		" bash deb shells required arch=any\n"+
+			" bash-doc deb doc optional arch=all\n")
+
+	buf := &bytes.Buffer{}
+	w := bufio.NewWriter(buf)
+	err = stanza.Copy().WriteTo(w, true, false, false)
+	c.Assert(err, IsNil)
+	c.Assert(w.Flush(), IsNil)
+
+	written := buf.String()
+	c.Assert(strings.Contains(written, "Package-List:\n \n"), Equals, false,
+		Commentf("spurious blank continuation line found in written output:\n%s", written))
+	c.Assert(strings.Contains(written, "Package-List:\n bash"), Equals, true,
+		Commentf("expected Package-List entries not found in written output:\n%s", written))
+}
+
 func (s *ControlFileSuite) TestReadWriteInstallerStanza(c *C) {
 	s.reader = bytes.NewBufferString(installerFile)
 	r := NewControlFileReader(s.reader, false, true)