Auto-generate the complete list of stdlib modules

The new script, mkstdlibs.py, uses intersphinx to dump a complete list
of Python stdlib modules to the files py3.txt/py27.txt. These files are
read by isort to decide if a module should be considered stdlib or not.

In the future, if the stdlib changes, the fix is to simply re-run the
script.

Fixes #985

1 files changed, 46 insertions, 0 deletions

diff --git a/scripts/mkstdlibs.py b/scripts/mkstdlibs.py
new file mode 100755
index 00000000..4a72c75c
--- /dev/null
+++ b/scripts/mkstdlibs.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+from sphinx.ext.intersphinx import fetch_inventory
+
+
+URL = "https://docs.python.org/{}/objects.inv"
+PATH = "isort/stdlibs/py{}.py"
+VERSIONS = [("2", "7"), ("3",)]
+
+DOCSTRING = """
+File contains the standard library of Python {}.
+
+DO NOT EDIT. If the standard library changes, a new list should be created
+using the mkstdlibs.py script.
+"""
+
+
+class FakeConfig:
+    intersphinx_timeout = None
+    tls_verify = True
+
+
+class FakeApp:
+    srcdir = ""
+    config = FakeConfig()
+
+
+for version_info in VERSIONS:
+    version = ".".join(version_info)
+    url = URL.format(version)
+    invdata = fetch_inventory(FakeApp(), "", url)
+
+    modules = set()
+    for module in invdata["py:module"]:
+        root, *_ = module.split(".")
+        if root not in ["__future__", "__main__"]:
+            modules.add(root)
+
+    path = PATH.format("".join(version_info))
+    with open(path, "w") as fp:
+        docstring = DOCSTRING.format(version)
+        fp.write('"""{}"""\n\n'.format(docstring))
+        fp.write("stdlib = [\n")
+        for module in sorted(modules):
+            fp.write('    "{}",\n'.format(module))
+        fp.write("]\n")