Source files: fix empty line in Package-List

deb/format.go

@@ -288,8 +288,14 @@ func (c *ControlFileReader) ReadStanza() (Stanza, error) {
 			lastField = canonicalCase(parts[0])
 			lastFieldMultiline = isMultilineField(lastField, c.isRelease)
 			if lastFieldMultiline {
-				stanza[lastField] = parts[1]
+				// Trim trailing whitespace from the inline value so that
-				if parts[1] != "" {
+				// "Package-List: " (trailing space, as used by Debian) is
+				// treated identically to "Package-List:" (no inline content).
+				// Without this, the trailing space is stored and later
+				// re-emitted as a spurious blank continuation line.
+				inlineVal := strings.TrimRight(parts[1], " \t")
+				stanza[lastField] = inlineVal
+				if inlineVal != "" {
 					stanza[lastField] += "\n"
 				}
 			} else {

deb/format_test.go

@@ -128,6 +128,42 @@ func (s *ControlFileSuite) TestReadWriteStanza(c *C) {
 	c.Assert(strings.HasPrefix(str, "Package: "), Equals, true)
 }
 
+// TestPackageListTrailingSpace is a regression test for
+// https://github.com/aptly-dev/aptly/issues/1538.
+// Upstream Debian Sources files write "Package-List: " with a trailing space
+// on the header line. 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 mirrors the format used by real Debian Sources files:
+	// the "Package-List:" header carries a trailing space, not bare colon.
+	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)
+
+	// The stored value must equal what a bare "Package-List:\n" header gives:
+	// no leading whitespace / blank line, just the continuation lines.
+	c.Check(stanza["Package-List"], Equals,
+		" bash deb shells required arch=any\n"+
+			" bash-doc deb doc optional arch=all\n")
+
+	// Round-trip: written output must not contain a spurious blank line.
+	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)