fix(python): fixed panic when scan .egg archive (fanal#446)

Co-authored-by: Teppei Fukuda <[email protected]>

Author: DmitriyLewen

analyzer/language/python/packaging/packaging.go

@@ -50,7 +50,12 @@ func (a packagingAnalyzer) Analyze(_ context.Context, input analyzer.AnalysisInp
 		if err != nil {
 			return nil, xerrors.Errorf("egg analysis error: %w", err)
 		}
+		if pkginfoInZip == nil { // Egg archive may not contain required files, then we will get nil. Skip this archives
+			return nil, nil
+		}
+
 		defer pkginfoInZip.Close()
+
 		r = pkginfoInZip
 	}
 

analyzer/language/python/packaging/packaging_test.go

@@ -97,6 +97,11 @@ func Test_packagingAnalyzer_Analyze(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:      "egg zip doesn't contain required files",
+			inputFile: "testdata/no-required-files.egg",
+			want:      nil,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {