fix: better clean up of file handles

syft/pkg/cataloger/binary/elf_package_cataloger.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 
+	"github.com/anchore/syft/internal"
 	"github.com/anchore/syft/internal/log"
 	"github.com/anchore/syft/internal/mimetype"
 	"github.com/anchore/syft/syft/artifact"
@@ -57,31 +58,13 @@ func (c *elfPackageCataloger) Catalog(_ context.Context, resolver file.Resolver)
 	// first find all ELF binaries that have notes
 	var notesByLocation = make(map[elfPackageKey][]elfBinaryPackageNotes)
 	for _, location := range locations {
-		reader, err := resolver.FileContentsByLocation(location)
+		notes, key, err := parseElfPackageNotes(resolver, location, c)
 		if err != nil {
-			return nil, nil, fmt.Errorf("unable to get binary contents %q: %w", location.Path(), err)
+			return nil, nil, err
 		}
-
-		notes, err := c.parseElfNotes(file.LocationReadCloser{
-			Location:   location,
-			ReadCloser: reader,
-		})
-		if err != nil {
-			log.WithFields("file", location.Path(), "error", err).Trace("unable to parse ELF notes")
-			continue
-		}
-
 		if notes == nil {
 			continue
 		}
-
-		notes.Location = location
-		key := elfPackageKey{
-			Name:    notes.Name,
-			Version: notes.Version,
-			PURL:    notes.PURL,
-			CPE:     notes.CPE,
-		}
 		notesByLocation[key] = append(notesByLocation[key], *notes)
 	}
 
@@ -105,6 +88,37 @@ func (c *elfPackageCataloger) Catalog(_ context.Context, resolver file.Resolver)
 	return pkgs, nil, nil
 }
 
+func parseElfPackageNotes(resolver file.Resolver, location file.Location, c *elfPackageCataloger) (*elfBinaryPackageNotes, elfPackageKey, error) {
+	reader, err := resolver.FileContentsByLocation(location)
+	if err != nil {
+		return nil, elfPackageKey{}, fmt.Errorf("unable to get binary contents %q: %w", location.Path(), err)
+	}
+	defer internal.CloseAndLogError(reader, location.AccessPath)
+
+	notes, err := c.parseElfNotes(file.LocationReadCloser{
+		Location:   location,
+		ReadCloser: reader,
+	})
+
+	if err != nil {
+		log.WithFields("file", location.Path(), "error", err).Trace("unable to parse ELF notes")
+		return nil, elfPackageKey{}, nil
+	}
+
+	if notes == nil {
+		return nil, elfPackageKey{}, nil
+	}
+
+	notes.Location = location
+	key := elfPackageKey{
+		Name:    notes.Name,
+		Version: notes.Version,
+		PURL:    notes.PURL,
+		CPE:     notes.CPE,
+	}
+	return notes, key, nil
+}
+
 func (c *elfPackageCataloger) parseElfNotes(reader file.LocationReadCloser) (*elfBinaryPackageNotes, error) {
 	metadata, err := getELFNotes(reader)
 	if err != nil {

syft/pkg/cataloger/generic/cataloger.go

@@ -3,6 +3,7 @@ package generic
 import (
 	"context"
 
+	"github.com/anchore/go-logger"
 	"github.com/anchore/syft/internal"
 	"github.com/anchore/syft/internal/log"
 	"github.com/anchore/syft/syft/artifact"
@@ -122,14 +123,7 @@ func (c *Cataloger) Catalog(ctx context.Context, resolver file.Resolver) ([]pkg.
 
 		log.WithFields("path", location.RealPath).Trace("parsing file contents")
 
-		contentReader, err := resolver.FileContentsByLocation(location)
-		if err != nil {
-			logger.WithFields("location", location.RealPath, "error", err).Warn("unable to fetch contents")
-			continue
-		}
-
-		discoveredPackages, discoveredRelationships, err := parser(ctx, resolver, &env, file.NewLocationReadCloser(location, contentReader))
-		internal.CloseAndLogError(contentReader, location.AccessPath)
+		discoveredPackages, discoveredRelationships, err := invokeParser(ctx, resolver, location, logger, parser, &env)
 		if err != nil {
 			logger.WithFields("location", location.RealPath, "error", err).Warnf("cataloger failed")
 			continue
@@ -145,6 +139,18 @@ func (c *Cataloger) Catalog(ctx context.Context, resolver file.Resolver) ([]pkg.
 	return packages, relationships, nil
 }
 
+func invokeParser(ctx context.Context, resolver file.Resolver, location file.Location, logger logger.Logger, parser Parser, env *Environment) ([]pkg.Package, []artifact.Relationship, error) {
+	contentReader, err := resolver.FileContentsByLocation(location)
+	if err != nil {
+		logger.WithFields("location", location.RealPath, "error", err).Warn("unable to fetch contents")
+		return nil, nil, nil
+	}
+	defer internal.CloseAndLogError(contentReader, location.AccessPath)
+
+	discoveredPackages, discoveredRelationships, err := parser(ctx, resolver, env, file.NewLocationReadCloser(location, contentReader))
+	return discoveredPackages, discoveredRelationships, err
+}
+
 // selectFiles takes a set of file trees and resolves and file references of interest for future cataloging
 func (c *Cataloger) selectFiles(resolver file.Resolver) []request {
 	var requests []request

syft/pkg/cataloger/generic/cataloger_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -86,3 +87,103 @@ func Test_Cataloger(t *testing.T) {
 		}
 	}
 }
+
+type spyReturningFileResolver struct {
+	m *file.MockResolver
+	s *spyingIoReadCloser
+}
+
+type spyingIoReadCloser struct {
+	rc     io.ReadCloser
+	closed bool
+}
+
+func newSpyReturningFileResolver(s *spyingIoReadCloser, paths ...string) file.Resolver {
+	m := file.NewMockResolverForPaths(paths...)
+	return spyReturningFileResolver{
+		m: m,
+		s: s,
+	}
+}
+
+func (s *spyingIoReadCloser) Read(p []byte) (n int, err error) {
+	return s.Read(p)
+}
+
+func (s *spyingIoReadCloser) Close() error {
+	s.closed = true
+	return s.rc.Close()
+}
+
+var _ io.ReadCloser = (*spyingIoReadCloser)(nil)
+
+func (m spyReturningFileResolver) FileContentsByLocation(location file.Location) (io.ReadCloser, error) {
+	return m.s, nil
+}
+
+func (m spyReturningFileResolver) HasPath(path string) bool {
+	return m.m.HasPath(path)
+}
+
+func (m spyReturningFileResolver) FilesByPath(paths ...string) ([]file.Location, error) {
+	return m.m.FilesByPath(paths...)
+}
+
+func (m spyReturningFileResolver) FilesByGlob(patterns ...string) ([]file.Location, error) {
+	return m.m.FilesByGlob(patterns...)
+}
+
+func (m spyReturningFileResolver) FilesByMIMEType(types ...string) ([]file.Location, error) {
+	return m.m.FilesByMIMEType(types...)
+}
+
+func (m spyReturningFileResolver) RelativeFileByPath(f file.Location, path string) *file.Location {
+	return m.m.RelativeFileByPath(f, path)
+}
+
+func (m spyReturningFileResolver) AllLocations(ctx context.Context) <-chan file.Location {
+	return m.m.AllLocations(ctx)
+}
+
+func (m spyReturningFileResolver) FileMetadataByLocation(location file.Location) (file.Metadata, error) {
+	return m.m.FileMetadataByLocation(location)
+}
+
+var _ file.Resolver = (*spyReturningFileResolver)(nil)
+
+func TestClosesFileOnParserPanic(t *testing.T) {
+	rc := io.NopCloser(strings.NewReader("some string"))
+	spy := spyingIoReadCloser{
+		rc: rc,
+	}
+	resolver := newSpyReturningFileResolver(&spy, "test-fixtures/another-path.txt")
+	ctx := context.TODO()
+
+	processors := []processor{
+		func(resolver file.Resolver, env Environment) []request {
+			return []request{
+				{
+					Location: file.Location{
+						LocationData: file.LocationData{
+							Coordinates: file.Coordinates{},
+							AccessPath:  "/some/access/path",
+						},
+					},
+					Parser: func(context.Context, file.Resolver, *Environment, file.LocationReadCloser) ([]pkg.Package, []artifact.Relationship, error) {
+						panic("panic!")
+					},
+				},
+			}
+		},
+	}
+
+	c := Cataloger{
+		processor:         processors,
+		upstreamCataloger: "unit-test-cataloger",
+	}
+
+	assert.PanicsWithValue(t, "panic!", func() {
+		_, _, _ = c.Catalog(ctx, resolver)
+	})
+	require.True(t, spy.closed)
+}