Prevent v2 imports from happening on systems with v3

ament_flake8/ament_flake8/legacy.py

@@ -14,62 +14,66 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import flake8.engine
-from flake8.reporter import QueueReport
+from distutils.version import LooseVersion
 
+import flake8
 
-class CustomReport(QueueReport):
+# Ensure that importing this module doesn't fail when imported on systems with flake8>=3.0.
+# This can happen during coverage tests on systems with flake8>=3.0, for example.
+if LooseVersion(flake8.__version__) < '3.0':
+    import flake8.engine
+    from flake8.reporter import QueueReport
 
-    errors = []
-    files = []
+    class CustomReport(QueueReport):
 
-    def error(self, line_number, offset, text, check):
-        code = super(CustomReport, self).error(
-            line_number, offset, text, check)
-        line = self.lines[line_number - 1] \
-            if line_number <= len(self.lines) else ''
-        self.errors.append({
-            'path': self.filename,
-            'row': self.line_offset + line_number,
-            'column': offset + 1,
-            'error_code': code,
-            'error_message': text,
-            'source_line': line.splitlines()[0] if line else '',
-        })
-        return code
+        errors = []
+        files = []
 
+        def error(self, line_number, offset, text, check):
+            code = super(CustomReport, self).error(
+                line_number, offset, text, check)
+            line = self.lines[line_number - 1] \
+                if line_number <= len(self.lines) else ''
+            self.errors.append({
+                'path': self.filename,
+                'row': self.line_offset + line_number,
+                'column': offset + 1,
+                'error_code': code,
+                'error_message': text,
+                'source_line': line.splitlines()[0] if line else '',
+            })
+            return code
 
-class CustomStyleGuide(flake8.engine.NoQAStyleGuide):
+    class CustomStyleGuide(flake8.engine.NoQAStyleGuide):
 
-    def input_file(self, filename, **kwargs):
-        self.options.reporter.files.append(filename)
-        return super(CustomStyleGuide, self).input_file(filename, **kwargs)
+        def input_file(self, filename, **kwargs):
+            self.options.reporter.files.append(filename)
+            return super(CustomStyleGuide, self).input_file(filename, **kwargs)
 
+    def generate_flake8_report(config_file, paths, excludes, max_line_length=None):
+        kwargs = {
+            'repeat': True,
+            'show_source': True,
+            'verbose': True,
+            'reporter': CustomReport,
+            'config_file': config_file,
+            'jobs': 1,
+        }
+        if max_line_length is not None:
+            kwargs['max_line_length'] = max_line_length
 
-def generate_flake8_report(config_file, paths, excludes, max_line_length=None):
-    kwargs = {
-        'repeat': True,
-        'show_source': True,
-        'verbose': True,
-        'reporter': CustomReport,
-        'config_file': config_file,
-        'jobs': 1,
-    }
-    if max_line_length is not None:
-        kwargs['max_line_length'] = max_line_length
+        # add options for flake8 plugins
+        kwargs['parser'], options_hooks = flake8.engine.get_parser()
+        flake8style = CustomStyleGuide(**kwargs)
+        options = flake8style.options
+        for options_hook in options_hooks:
+            options_hook(options)
 
-    # add options for flake8 plugins
-    kwargs['parser'], options_hooks = flake8.engine.get_parser()
-    flake8style = CustomStyleGuide(**kwargs)
-    options = flake8style.options
-    for options_hook in options_hooks:
-        options_hook(options)
+        if excludes:
+            flake8style.options.exclude += excludes
 
-    if excludes:
-        flake8style.options.exclude += excludes
+        # flake8 uses a wrapper StyleGuide to handle some particular OSErrors
+        kwargs['styleguide'] = flake8style
+        wrapperStyleGuide = flake8.engine.StyleGuide(**kwargs)
 
-    # flake8 uses a wrapper StyleGuide to handle some particular OSErrors
-    kwargs['styleguide'] = flake8style
-    wrapperStyleGuide = flake8.engine.StyleGuide(**kwargs)
-
-    return wrapperStyleGuide.check_files(paths)
+        return wrapperStyleGuide.check_files(paths)