make unsed loop control variables underscoresfrazer/flake8

14 files changed, 43 insertions, 30 deletions

diff --git a/doc/source/conf.py b/doc/source/conf.py
index 269053675..3ae20247b 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -245,21 +245,21 @@ htmlhelp_basename = 'BuildStreamdoc'
 # -- Options for LaTeX output ---------------------------------------------
 
 latex_elements = {
-     # The paper size ('letterpaper' or 'a4paper').
-     #
-     # 'papersize': 'letterpaper',
+    # The paper size ('letterpaper' or 'a4paper').
+    #
+    # 'papersize': 'letterpaper',
 
-     # The font size ('10pt', '11pt' or '12pt').
-     #
-     # 'pointsize': '10pt',
+    # The font size ('10pt', '11pt' or '12pt').
+    #
+    # 'pointsize': '10pt',
 
-     # Additional stuff for the LaTeX preamble.
-     #
-     # 'preamble': '',
+    # Additional stuff for the LaTeX preamble.
+    #
+    # 'preamble': '',
 
-     # Latex figure (float) alignment
-     #
-     # 'figure_align': 'htbp',
+    # Latex figure (float) alignment
+    #
+    # 'figure_align': 'htbp',
 }
 
 # Grouping the document tree into LaTeX files. List of tuples
diff --git a/src/buildstream/_elementfactory.py b/src/buildstream/_elementfactory.py
index 5d219c627..e4705c12a 100644
--- a/src/buildstream/_elementfactory.py
+++ b/src/buildstream/_elementfactory.py
@@ -30,7 +30,9 @@ from .element import Element
 #     plugin_origins (list):    Data used to search for external Element plugins
 #
 class ElementFactory(PluginContext):
-    def __init__(self, plugin_base, *, format_versions={}, plugin_origins=None):
+    def __init__(self, plugin_base, *, format_versions=None, plugin_origins=None):
+        if format_versions is None:
+            format_versions = {}
 
         super().__init__(
             plugin_base,
diff --git a/src/buildstream/_frontend/widget.py b/src/buildstream/_frontend/widget.py
index 63fbfbb7d..2e2f32bc0 100644
--- a/src/buildstream/_frontend/widget.py
+++ b/src/buildstream/_frontend/widget.py
@@ -761,7 +761,7 @@ class LogLine(Widget):
     def _format_values(self, values, style_value=True):
         text = ""
         max_key_len = 0
-        for key, value in values.items():
+        for key, _ in values.items():
             max_key_len = max(len(key), max_key_len)
 
         for key, value in values.items():
diff --git a/src/buildstream/_gitsourcebase.py b/src/buildstream/_gitsourcebase.py
index 4e9e59161..739ae5169 100644
--- a/src/buildstream/_gitsourcebase.py
+++ b/src/buildstream/_gitsourcebase.py
@@ -53,14 +53,17 @@ class _RefFormat(FastEnum):
 # might have at a given time
 #
 class _GitMirror(SourceFetcher):
-    def __init__(self, source, path, url, ref, *, primary=False, tags=[]):
+    def __init__(self, source, path, url, ref, *, primary=False, tags=None):
 
         super().__init__()
         self.source = source
         self.path = path
         self.url = url
         self.ref = ref
-        self.tags = tags
+        if tags is None:
+            self.tags = []
+        else:
+            self.tags = tags
         self.primary = primary
         self.mirror = os.path.join(source.get_mirror_directory(), utils.url_directory_name(url))
         self.mark_download_url(url)
diff --git a/src/buildstream/_includes.py b/src/buildstream/_includes.py
index bc0d7718b..c01ffda24 100644
--- a/src/buildstream/_includes.py
+++ b/src/buildstream/_includes.py
@@ -28,7 +28,9 @@ class Includes:
     #    included (set): Fail for recursion if trying to load any files in this set
     #    current_loader (Loader): Use alternative loader (for junction files)
     #    only_local (bool): Whether to ignore junction files
-    def process(self, node, *, included=set(), current_loader=None, only_local=False):
+    def process(self, node, *, included=None, current_loader=None, only_local=False):
+        if included is None:
+            included = set()
         if current_loader is None:
             current_loader = self._loader
 
@@ -118,9 +120,12 @@ class Includes:
     #    included (set): Fail for recursion if trying to load any files in this set
     #    current_loader (Loader): Use alternative loader (for junction files)
     #    only_local (bool): Whether to ignore junction files
-    def _process_value(self, value, *, included=set(), current_loader=None, only_local=False):
+    def _process_value(self, value, *, included=None, current_loader=None, only_local=False):
         value_type = type(value)
 
+        if included is None:
+            included = set()
+
         if value_type is MappingNode:
             self.process(value, included=included, current_loader=current_loader, only_local=only_local)
         elif value_type is SequenceNode:
diff --git a/src/buildstream/_plugincontext.py b/src/buildstream/_plugincontext.py
index 54839e16b..19d9e4469 100644
--- a/src/buildstream/_plugincontext.py
+++ b/src/buildstream/_plugincontext.py
@@ -42,7 +42,7 @@ from . import utils
 # Pipelines.
 #
 class PluginContext:
-    def __init__(self, plugin_base, base_type, site_plugin_path, *, plugin_origins=None, format_versions={}):
+    def __init__(self, plugin_base, base_type, site_plugin_path, *, plugin_origins=None, format_versions=None):
 
         # For pickling across processes, make sure this context has a unique
         # identifier, which we prepend to the identifier of each PluginSource.
@@ -64,7 +64,10 @@ class PluginContext:
         self._plugin_base = plugin_base
         self._site_plugin_path = site_plugin_path
         self._alternate_sources = {}
-        self._format_versions = format_versions
+        if format_versions is None:
+            self._format_versions = {}
+        else:
+            self._format_versions = format_versions
 
         self._init_site_source()
 
diff --git a/src/buildstream/_sourcefactory.py b/src/buildstream/_sourcefactory.py
index 7c90042a8..833c334d0 100644
--- a/src/buildstream/_sourcefactory.py
+++ b/src/buildstream/_sourcefactory.py
@@ -30,7 +30,9 @@ from .source import Source
 #     plugin_origins (list):    Data used to search for external Source plugins
 #
 class SourceFactory(PluginContext):
-    def __init__(self, plugin_base, *, format_versions={}, plugin_origins=None):
+    def __init__(self, plugin_base, *, format_versions=None, plugin_origins=None):
+        if format_versions is None:
+            format_versions = {}
 
         super().__init__(
             plugin_base, Source, [_site.source_plugins], format_versions=format_versions, plugin_origins=plugin_origins
diff --git a/src/buildstream/_version.py b/src/buildstream/_version.py
index 10905c4ea..cb440d6cd 100644
--- a/src/buildstream/_version.py
+++ b/src/buildstream/_version.py
@@ -115,7 +115,7 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {
@@ -507,7 +507,7 @@ def get_versions():
         # versionfile_source is the relative path from the top of the source
         # tree (where the .git directory might live) to this file. Invert
         # this to find the root from __file__.
-        for i in cfg.versionfile_source.split("/"):
+        for _ in cfg.versionfile_source.split("/"):
             root = os.path.dirname(root)
     except NameError:
         return {
diff --git a/src/buildstream/plugins/sources/local.py b/src/buildstream/plugins/sources/local.py
index b82fd95d2..fe28051c3 100644
--- a/src/buildstream/plugins/sources/local.py
+++ b/src/buildstream/plugins/sources/local.py
@@ -39,7 +39,6 @@ details on common configuration options for sources.
 import os
 from buildstream.storage.directory import Directory
 from buildstream import Source, SourceError, Consistency
-from buildstream import utils
 
 
 class LocalSource(Source):
diff --git a/src/buildstream/plugins/sources/workspace.py b/src/buildstream/plugins/sources/workspace.py
index c92ba0c6b..0969e944c 100644
--- a/src/buildstream/plugins/sources/workspace.py
+++ b/src/buildstream/plugins/sources/workspace.py
@@ -35,11 +35,8 @@ workspace. The node constructed would be specified as follows:
    path: /path/to/workspace
 """
 
-import os
 from buildstream.storage.directory import Directory
-from buildstream.storage._casbaseddirectory import CasBasedDirectory
 from buildstream import Source, SourceError, Consistency
-from buildstream import utils
 from buildstream.types import SourceRef
 from buildstream.node import MappingNode
 
diff --git a/src/buildstream/storage/_casbaseddirectory.py b/src/buildstream/storage/_casbaseddirectory.py
index df28dc591..00dd0aff3 100644
--- a/src/buildstream/storage/_casbaseddirectory.py
+++ b/src/buildstream/storage/_casbaseddirectory.py
@@ -531,10 +531,10 @@ class CasBasedDirectory(Directory):
         if prefix != "":
             yield prefix
 
-        for (k, v) in sorted(file_list):
+        for k, _ in sorted(file_list):
             yield os.path.join(prefix, k)
 
-        for (k, v) in sorted(directory_list):
+        for k, v in sorted(directory_list):
             subdir = v.get_directory(self)
             yield from subdir._list_prefixed_relative_paths(prefix=os.path.join(prefix, k))
 
diff --git a/src/buildstream/testing/_fixtures.py b/src/buildstream/testing/_fixtures.py
index 5da51bb45..dd7c5e9d2 100644
--- a/src/buildstream/testing/_fixtures.py
+++ b/src/buildstream/testing/_fixtures.py
@@ -19,6 +19,7 @@ import pytest
 
 from buildstream import node, utils
 
+
 # Catch tests that don't shut down background threads, which could then lead
 # to other tests hanging when BuildStream uses fork().
 @pytest.fixture(autouse=True)
diff --git a/tests/frontend/push.py b/tests/frontend/push.py
index 583b57399..934140175 100644
--- a/tests/frontend/push.py
+++ b/tests/frontend/push.py
@@ -261,6 +261,7 @@ def test_push_all(cli, tmpdir, datafiles):
         assert_shared(cli, share, project, "compose-all.bst")
 
 
+
 # Tests that `bst artifact push --deps run $artifact_ref` fails
 @pytest.mark.datafiles(DATA_DIR)
 def test_push_artifacts_all_deps_fails(cli, tmpdir, datafiles):
diff --git a/versioneer.py b/versioneer.py
index 1c97e0227..cf3d38819 100644
--- a/versioneer.py
+++ b/versioneer.py
@@ -1167,7 +1167,7 @@ def versions_from_parentdir(parentdir_prefix, root, verbose):
     """
     rootdirs = []
 
-    for i in range(3):
+    for _ in range(3):
         dirname = os.path.basename(root)
         if dirname.startswith(parentdir_prefix):
             return {"version": dirname[len(parentdir_prefix):],