Add reports extra to setup.py (python#11777)

Author: jamesbraza

docs/source/command_line.rst

@@ -853,13 +853,17 @@ format into the specified directory.
 
     Causes mypy to generate a Cobertura XML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. option:: --html-report / --xslt-html-report DIR
 
     Causes mypy to generate an HTML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. option:: --linecount-report DIR
 
@@ -881,13 +885,17 @@ format into the specified directory.
 
     Causes mypy to generate a text file type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. option:: --xml-report DIR
 
     Causes mypy to generate an XML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 Miscellaneous
 *************

docs/source/config_file.rst

@@ -820,15 +820,19 @@ format into the specified directory.
 
     Causes mypy to generate a Cobertura XML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. confval:: html_report / xslt_html_report
 
     :type: string
 
     Causes mypy to generate an HTML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. confval:: linecount_report
 
@@ -858,15 +862,19 @@ format into the specified directory.
 
     Causes mypy to generate a text file type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 .. confval:: xml_report
 
     :type: string
 
     Causes mypy to generate an XML type checking coverage report.
 
-    You must install the `lxml`_ library to generate this report.
+    To generate this report, you must either manually install the `lxml`_
+    library or specify mypy installation with the setuptools extra
+    ``mypy[reports]``.
 
 
 Miscellaneous

setup.py

@@ -201,7 +201,11 @@ def run(self):
                         'tomli>=1.1.0',
                         ],
       # Same here.
-      extras_require={'dmypy': 'psutil >= 4.0', 'python2': 'typed_ast >= 1.4.0, < 2'},
+      extras_require={
+          'dmypy': 'psutil >= 4.0',
+          'python2': 'typed_ast >= 1.4.0, < 2',
+          'reports': 'lxml'
+      },
       python_requires=">=3.6",
       include_package_data=True,
       project_urls={