Return ErrUnexpectedEOF from Parser.Single

Author: zombiezen

internal/deb/control.go

@@ -79,7 +79,8 @@ func NewParser(r io.Reader) *Parser {
 // Single parses a single-paragraph control file, which will then be available
 // through the Paragraph method. It returns false if the method is called after
 // any call to Next, the parser stops before reading a paragraph, or the parser
-// encounters a syntax error.
+// encounters a syntax error. If Single returns false, Err() will always return
+// an error.
 func (p *Parser) Single() bool {
 	if p.err != nil {
 		return false
@@ -90,6 +91,9 @@ func (p *Parser) Single() bool {
 		return false
 	}
 	if !p.Next() {
+		if p.err == nil {
+			p.err = fmt.Errorf("parse debian control file: %w", io.ErrUnexpectedEOF)
+		}
 		return false
 	}
 

internal/deb/release.go

@@ -28,21 +28,20 @@ import (
 // https://wiki.debian.org/DebianRepository/Format#A.22Release.22_files
 func ParseReleaseIndex(r io.Reader) (Paragraph, error) {
 	p := NewParser(r)
-	p.Fields = map[string]FieldType{
-		"MD5Sum": Multiline,
-		"SHA1":   Multiline,
-		"SHA256": Multiline,
-	}
+	p.Fields = ReleaseFields
 	if !p.Single() {
-		err := p.Err()
-		if err == nil {
-			err = io.ErrUnexpectedEOF
-		}
-		return nil, fmt.Errorf("parse Release: %w", err)
+		return nil, fmt.Errorf("parse Release: %w", p.Err())
 	}
 	return p.Paragraph(), nil
 }
 
+// ReleaseFields is the set of fields in the release information file.
+var ReleaseFields = map[string]FieldType{
+	"MD5Sum": Multiline,
+	"SHA1":   Multiline,
+	"SHA256": Multiline,
+}
+
 type IndexSignature struct {
 	Checksum []byte
 	Size     int64

upload.go

@@ -183,10 +183,7 @@ func uploadBinaryPackage(ctx context.Context, bucket *blob.Bucket, debPath strin
 	p := deb.NewParser(bytes.NewReader(control))
 	p.Fields = deb.ControlFields
 	if !p.Single() {
-		if err := p.Err(); err != nil {
-			return nil, fmt.Errorf("upload binary package %s: control: %w", debName, err)
-		}
-		return nil, fmt.Errorf("upload binary package %s: control: empty file", debName)
+		return nil, fmt.Errorf("upload binary package %s: control: %w", debName, p.Err())
 	}
 	pkg := p.Paragraph()
 	promotePackageField(pkg)
@@ -218,10 +215,7 @@ func uploadSourcePackage(ctx context.Context, bucket *blob.Bucket, dscPath strin
 	p := deb.NewParser(bytes.NewReader(maybeClearSigned(dsc)))
 	p.Fields = deb.SourceControlFields
 	if !p.Single() {
-		if err := p.Err(); err != nil {
-			return nil, fmt.Errorf("upload source package %s: %w", packageName, err)
-		}
-		return nil, fmt.Errorf("upload source package %s: empty file", packageName)
+		return nil, fmt.Errorf("upload source package %s: %w", packageName, p.Err())
 	}
 	pkg := p.Paragraph()
 	dir := poolPath(packageName)