style: streamline code quality

.flake8

@@ -0,0 +1,20 @@
+[flake8]
+## https://flake8.pycqa.org/en/latest/user/configuration.html
+## keep in sync with isort config - in `isort.cfg` file
+
+exclude =
+    build,dist,__pycache__,.eggs,*.egg-info*,
+    *_cache,*.cache,
+    .git,.tox,.venv,venv,.venv*,venv*,
+    _OLD,_TEST,
+    docs
+
+max-line-length = 120
+
+max-complexity = 20
+
+ignore =
+    # ignore `self`, `cls` markers of flake8-annotations>=2.0
+    ANN101,ANN102
+    # ignore ANN401 for dynamically typed *args and **kwargs
+    ANN401

.isort.cfg

@@ -1,6 +1,6 @@
 [settings]
 ## read the docs: https://pycqa.github.io/isort/docs/configuration/options.html
-## keep in sync with flake8 config - in `tox.ini` file
+## keep in sync with flake8 config - in `.flake8` file
 known_first_party = cyclonedx
 skip_gitignore = false
 skip_glob =

CONTRIBUTING.md

@@ -26,6 +26,10 @@ poetry run isort .
 poetry run autopep8 -ir cyclonedx/ tests/ typings/ examples/
 ```
 
+This project prefers `f'strings'` over `'string'.format()`.  
+This project prefers `'single quotes'` over `"double quotes"`.  
+This project prefers `lower_snake_case` variable names.  
+
 ## Documentation
 
 This project uses [Sphinx] to generate documentation which is automatically published to [readthedocs.io].

cyclonedx/__init__.py

@@ -20,4 +20,5 @@
 
 # !! version is managed by semantic_release
 # do not use typing here, or else `semantic_release` might have issues finding the variable
+# flake8: noqa
 __version__ = "5.0.0-rc.1"

cyclonedx/exception/__init__.py

@@ -19,13 +19,13 @@
 """
 
 
-class CycloneDxException(Exception):
+class CycloneDxException(Exception):  # noqa: N818
     """
     Root exception thrown by this library.
     """
     pass
 
 
-class MissingOptionalDependencyException(CycloneDxException):
+class MissingOptionalDependencyException(CycloneDxException):  # noqa: N818
     """Validation did not happen, due to missing dependencies."""
     pass

cyclonedx/model/__init__.py

@@ -23,7 +23,7 @@
 import serializable
 from sortedcontainers import SortedSet
 
-from .. import __version__ as __ThisToolVersion
+from .. import __version__ as __ThisToolVersion  # noqa: N812
 from ..exception.model import (
     InvalidLocaleTypeException,
     InvalidUriException,
@@ -57,7 +57,7 @@ def sha1sum(filename: str) -> str:
     """
     h = sha1()
     with open(filename, 'rb') as f:
-        for byte_block in iter(lambda: f.read(4096), b""):
+        for byte_block in iter(lambda: f.read(4096), b''):
             h.update(byte_block)
     return h.hexdigest()
 
@@ -102,10 +102,10 @@ class DataFlow(str, Enum):
     .. note::
         See the CycloneDX Schema: https://cyclonedx.org/docs/1.4/xml/#type_dataFlowType
     """
-    INBOUND = "inbound"
-    OUTBOUND = "outbound"
-    BI_DIRECTIONAL = "bi-directional"
-    UNKNOWN = "unknown"
+    INBOUND = 'inbound'
+    OUTBOUND = 'outbound'
+    BI_DIRECTIONAL = 'bi-directional'
+    UNKNOWN = 'unknown'
 
 
 @serializable.serializable_class
@@ -325,16 +325,16 @@ def from_composite_str(composite_hash: str) -> 'HashType':
             )
         elif algorithm_prefix[0:3] == 'sha':
             return HashType(
-                alg=getattr(HashAlgorithm, 'SHA_{}'.format(algorithm_prefix[3:])),
+                alg=getattr(HashAlgorithm, f'SHA_{algorithm_prefix[3:]}'),
                 content=parts[1].lower()
             )
         elif algorithm_prefix[0:6] == 'blake2':
             return HashType(
-                alg=getattr(HashAlgorithm, 'BLAKE2b_{}'.format(algorithm_prefix[6:])),
+                alg=getattr(HashAlgorithm, f'BLAKE2b_{algorithm_prefix[6:]}'),
                 content=parts[1].lower()
             )
 
-        raise UnknownHashTypeException(f"Unable to determine hash type from '{composite_hash}'")
+        raise UnknownHashTypeException(f'Unable to determine hash type from {composite_hash!r}')
 
     def __init__(self, *, alg: HashAlgorithm, content: str) -> None:
         self.alg = alg
@@ -542,7 +542,7 @@ def type(self, type: ExternalReferenceType) -> None:
     @serializable.view(SchemaVersion1Dot3)
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'hash')
-    def hashes(self) -> "SortedSet[HashType]":
+    def hashes(self) -> 'SortedSet[HashType]':
         """
         The hashes of the external reference (if applicable).
 
@@ -779,9 +779,9 @@ def locale(self, locale: Optional[str]) -> None:
             if not re.search(Note._LOCALE_TYPE_REGEX, locale):
                 self._locale = None
                 raise InvalidLocaleTypeException(
-                    f"Supplied locale '{locale}' is not a valid locale. "
-                    f"Locale string should be formatted as the ISO-639 (or higher) language code and optional "
-                    f"ISO-3166 (or higher) country code. according to ISO-639 format. Examples include: 'en', 'en-US'."
+                    f'Supplied locale {locale!r} is not a valid locale.'
+                    ' Locale string should be formatted as the ISO-639 (or higher) language code and optional'
+                    " ISO-3166 (or higher) country code. according to ISO-639 format. Examples include: 'en', 'en-US'."
                 )
 
     def __eq__(self, other: object) -> bool:
@@ -922,7 +922,7 @@ def name(self, name: Optional[str]) -> None:
     @serializable.json_name('url')
     @serializable.xml_array(serializable.XmlArraySerializationType.FLAT, 'url')
     @serializable.xml_sequence(2)
-    def urls(self) -> "SortedSet[XsUri]":
+    def urls(self) -> 'SortedSet[XsUri]':
         """
         Get a list of URLs of the organization. Multiple URLs are allowed.
 
@@ -939,7 +939,7 @@ def urls(self, urls: Iterable[XsUri]) -> None:
     @serializable.json_name('contact')
     @serializable.xml_array(serializable.XmlArraySerializationType.FLAT, 'contact')
     @serializable.xml_sequence(3)
-    def contacts(self) -> "SortedSet[OrganizationalContact]":
+    def contacts(self) -> 'SortedSet[OrganizationalContact]':
         """
         Get a list of contact person at the organization. Multiple contacts are allowed.
 
@@ -1037,7 +1037,7 @@ def version(self, version: Optional[str]) -> None:
     @property
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'hash')
     @serializable.xml_sequence(4)
-    def hashes(self) -> "SortedSet[HashType]":
+    def hashes(self) -> 'SortedSet[HashType]':
         """
         The hashes of the tool (if applicable).
 
@@ -1054,7 +1054,7 @@ def hashes(self, hashes: Iterable[HashType]) -> None:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'reference')
     @serializable.xml_sequence(5)
-    def external_references(self) -> "SortedSet[ExternalReference]":
+    def external_references(self) -> 'SortedSet[ExternalReference]':
         """
         External References provide a way to document systems, sites, and information that may be relevant but which
         are not included with the BOM.

cyclonedx/model/bom.py

@@ -94,7 +94,7 @@ def timestamp(self, timestamp: datetime) -> None:
     @property
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'tool')
     @serializable.xml_sequence(2)
-    def tools(self) -> "SortedSet[Tool]":
+    def tools(self) -> 'SortedSet[Tool]':
         """
         Tools used to create this BOM.
 
@@ -110,7 +110,7 @@ def tools(self, tools: Iterable[Tool]) -> None:
     @property
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'author')
     @serializable.xml_sequence(3)
-    def authors(self) -> "SortedSet[OrganizationalContact]":
+    def authors(self) -> 'SortedSet[OrganizationalContact]':
         """
         The person(s) who created the BOM.
 
@@ -207,7 +207,7 @@ def licenses(self, licenses: Iterable[License]) -> None:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'property')
     @serializable.xml_sequence(8)
-    def properties(self) -> "SortedSet[Property]":
+    def properties(self) -> 'SortedSet[Property]':
         """
         Provides the ability to document properties in a key/value store. This provides flexibility to include data not
         officially supported in the standard without having to use additional namespaces or create extensions.
@@ -335,7 +335,7 @@ def metadata(self, metadata: BomMetaData) -> None:
     @serializable.include_none(SchemaVersion1Dot1)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'component')
     @serializable.xml_sequence(2)
-    def components(self) -> "SortedSet[Component]":
+    def components(self) -> 'SortedSet[Component]':
         """
         Get all the Components currently in this Bom.
 
@@ -348,7 +348,7 @@ def components(self) -> "SortedSet[Component]":
     def components(self, components: Iterable[Component]) -> None:
         self._components = SortedSet(components)
 
-    def get_component_by_purl(self, purl: Optional["PackageURL"]) -> Optional[Component]:
+    def get_component_by_purl(self, purl: Optional['PackageURL']) -> Optional[Component]:
         """
         Get a Component already in the Bom by its PURL
 
@@ -394,7 +394,7 @@ def has_component(self, component: Component) -> bool:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'service')
     @serializable.xml_sequence(3)
-    def services(self) -> "SortedSet[Service]":
+    def services(self) -> 'SortedSet[Service]':
         """
         Get all the Services currently in this Bom.
 
@@ -414,7 +414,7 @@ def services(self, services: Iterable[Service]) -> None:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'reference')
     @serializable.xml_sequence(4)
-    def external_references(self) -> "SortedSet[ExternalReference]":
+    def external_references(self) -> 'SortedSet[ExternalReference]':
         """
         Provides the ability to document external references related to the BOM or to the project the BOM describes.
 
@@ -438,7 +438,7 @@ def _get_all_components(self) -> Set[Component]:
 
         return components
 
-    def get_vulnerabilities_for_bom_ref(self, bom_ref: BomRef) -> "SortedSet[Vulnerability]":
+    def get_vulnerabilities_for_bom_ref(self, bom_ref: BomRef) -> 'SortedSet[Vulnerability]':
         """
         Get all known Vulnerabilities that affect the supplied bom_ref.
 
@@ -469,7 +469,7 @@ def has_vulnerabilities(self) -> bool:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'vulnerability')
     @serializable.xml_sequence(8)
-    def vulnerabilities(self) -> "SortedSet[Vulnerability]":
+    def vulnerabilities(self) -> 'SortedSet[Vulnerability]':
         """
         Get all the Vulnerabilities in this BOM.
 
@@ -497,7 +497,7 @@ def version(self, version: int) -> None:
     @serializable.view(SchemaVersion1Dot4)
     @serializable.xml_array(serializable.XmlArraySerializationType.NESTED, 'dependency')
     @serializable.xml_sequence(5)
-    def dependencies(self) -> "SortedSet[Dependency]":
+    def dependencies(self) -> 'SortedSet[Dependency]':
         return self._dependencies
 
     @dependencies.setter
@@ -564,7 +564,7 @@ def validate(self) -> bool:
                 f'The Component this BOM is describing {self.metadata.component.purl} has no defined dependencies '
                 f'which means the Dependency Graph is incomplete - you should add direct dependencies to this '
                 f'"root" Component to complete the Dependency Graph data.',
-                UserWarning
+                category=UserWarning, stacklevel=1
             )
 
         # 3. If a LicenseExpression is set, then there must be no other license.