Introduce relationships as first-class objects (#607)

* migrate pkg.ID and pkg.Relationship to artifact package

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* return relationships from tasks

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* fix more tests

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add artifact.Identifiable by Identity() method

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* fix linting

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* remove catalog ID assignment

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* adjust spdx helpers to use copy of packages

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* stabilize package ID relative to encode-decode format cycles

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* rename Identity() to ID()

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* use zero value for nils in ID generation

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* enable source.Location to be identifiable

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* hoist up package relationship discovery to analysis stage

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* update ownership-by-file-overlap relationship description

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* add test reminders to put new relationships under test

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* adjust PHP composer.lock parser function to return relationships

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/pkg/cataloger/ruby/parse_gemfile_lock.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/anchore/syft/internal"
+	"github.com/anchore/syft/syft/artifact"
 	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/pkg/cataloger/common"
 )
@@ -16,7 +17,7 @@ var _ common.ParserFn = parseGemFileLockEntries
 var sectionsOfInterest = internal.NewStringSetFromSlice([]string{"GEM"})
 
 // parseGemFileLockEntries is a parser function for Gemfile.lock contents, returning all Gems discovered.
-func parseGemFileLockEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
+func parseGemFileLockEntries(_ string, reader io.Reader) ([]pkg.Package, []artifact.Relationship, error) {
 	pkgs := make([]pkg.Package, 0)
 	scanner := bufio.NewScanner(reader)
 
@@ -49,9 +50,9 @@ func parseGemFileLockEntries(_ string, reader io.Reader) ([]pkg.Package, error)
 		}
 	}
 	if err := scanner.Err(); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	return pkgs, nil
+	return pkgs, nil, nil
 }
 
 func isDependencyLine(line string) bool {

syft/pkg/cataloger/ruby/parse_gemfile_lock_test.go

@@ -68,7 +68,8 @@ func TestParseGemfileLockEntries(t *testing.T) {
 		t.Fatalf("failed to open fixture: %+v", err)
 	}
 
-	actual, err := parseGemFileLockEntries(fixture.Name(), fixture)
+	// TODO: no relationships are under test yet
+	actual, _, err := parseGemFileLockEntries(fixture.Name(), fixture)
 	if err != nil {
 		t.Fatalf("failed to parse gemfile lock: %+v", err)
 	}

syft/pkg/cataloger/ruby/parse_gemspec.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/mitchellh/mapstructure"
 
+	"github.com/anchore/syft/syft/artifact"
 	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/pkg/cataloger/common"
 )
@@ -60,7 +61,7 @@ func processList(s string) []string {
 	return results
 }
 
-func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
+func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, []artifact.Relationship, error) {
 	var pkgs []pkg.Package
 	var fields = make(map[string]interface{})
 	scanner := bufio.NewScanner(reader)
@@ -93,7 +94,7 @@ func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
 	if fields["name"] != "" && fields["version"] != "" {
 		var metadata pkg.GemMetadata
 		if err := mapstructure.Decode(fields, &metadata); err != nil {
-			return nil, fmt.Errorf("unable to decode gem metadata: %w", err)
+			return nil, nil, fmt.Errorf("unable to decode gem metadata: %w", err)
 		}
 
 		pkgs = append(pkgs, pkg.Package{
@@ -107,7 +108,7 @@ func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
 		})
 	}
 
-	return pkgs, nil
+	return pkgs, nil, nil
 }
 
 // renderUtf8 takes any string escaped string sub-sections from the ruby string and replaces those sections with the UTF8 runes.

syft/pkg/cataloger/ruby/parse_gemspec_test.go

@@ -31,7 +31,8 @@ func TestParseGemspec(t *testing.T) {
 		t.Fatalf("failed to open fixture: %+v", err)
 	}
 
-	actual, err := parseGemSpecEntries(fixture.Name(), fixture)
+	// TODO: no relationships are under test yet
+	actual, _, err := parseGemSpecEntries(fixture.Name(), fixture)
 	if err != nil {
 		t.Fatalf("failed to parse gemspec: %+v", err)
 	}