Merge pull request #51 from rauls5382/empty

Allow profiles with no samples

internal/driver/driver.go

 		}
 	}
 
-	if len(p.Sample) == 0 {
-		return fmt.Errorf("profile is empty")
-	}
-
 	if err := aggregate(p, vars); err != nil {
 		return err
 	}

profile/legacy_profile.go

 func parseHeap(b []byte) (p *Profile, err error) {
 	s := bufio.NewScanner(bytes.NewBuffer(b))
 	if !s.Scan() {
-		return nil, s.Err()
+		if err := s.Err(); err != nil {
+			return nil, err
+		}
+		return nil, errUnrecognized
 	}
 	p = &Profile{}
 
 func parseContention(b []byte) (p *Profile, err error) {
 	s := bufio.NewScanner(bytes.NewBuffer(b))
 	if !s.Scan() {
-		return nil, s.Err()
+		if err := s.Err(); err != nil {
+			return nil, err
+		}
+		return nil, errUnrecognized
 	}
 	line := s.Text()
 
 
 		addrs = append(addrs, parseHexAddresses(line)...)
 	}
-	if s.Err() != nil {
-		return "", nil, s.Err()
+	if err := s.Err(); err != nil {
+		return "", nil, err
 	}
 	if sameAsPrevious {
 		return line, nil, nil

profile/profile_test.go

 	"path/filepath"
 	"reflect"
 	"regexp"
+	"strings"
 	"testing"
 
 	"github.com/google/pprof/internal/proftest"
 	}
 }
 
+func TestParseError(t *testing.T) {
+
+	testcases := []string{
+		"",
+		"garbage text",
+		"\x1f\x8b", // truncated gzip header
+		"\x1f\x8b\x08\x08\xbe\xe9\x20\x58\x00\x03\x65\x6d\x70\x74\x79\x00\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", // empty gzipped file
+	}
+
+	for i, input := range testcases {
+		_, err := Parse(strings.NewReader(input))
+		if err == nil {
+			t.Errorf("got nil, want error for input #%d", i)
+		}
+	}
+}
+
 // leaveTempfile leaves |b| in a temporary file on disk and returns the
 // temp filename. This is useful to recover a profile when the test
 // fails.