Python: Fix FPs for py/import-own-module

Before I added `--max-import-depth=2`, there was a bit of trouble, where it
would alert on `from pkg_ok import foo2` -- since all the `pkg_ok.foo<n>`
modules were missing, I guess the analysis didn't make any assumptions on
whether `foo2` is a module or a regular attribute.

Author: RasmusWL

python/ql/src/Imports/ModuleImportsItself.ql

@@ -14,7 +14,12 @@ import python
 
 predicate modules_imports_itself(Import i, ModuleValue m) {
     i.getEnclosingModule() = m.getScope() and
-    m.importedAs(i.getAnImportedModuleName())
+    m = max(string s, ModuleValue m_ |
+            s = i.getAnImportedModuleName() and
+            m_.importedAs(s)
+        |
+            m_ order by s.length()
+        )
 }
 
 from Import i, ModuleValue m

python/ql/test/query-tests/Imports/PyCheckerTests/ModuleImportsItself.expected

@@ -1,10 +1,4 @@
 | imports_test.py:8:1:8:19 | Import | The module 'imports_test' imports itself. |
 | pkg_notok/__init__.py:4:1:4:16 | Import | The module 'pkg_notok' imports itself. |
-| pkg_notok/__init__.py:10:1:10:20 | Import | The module 'pkg_notok' imports itself. |
 | pkg_notok/__init__.py:12:1:12:25 | Import | The module 'pkg_notok' imports itself. |
 | pkg_notok/__init__.py:13:1:13:37 | Import | The module 'pkg_notok' imports itself. |
-| pkg_ok/__init__.py:1:1:1:26 | Import | The module 'pkg_ok' imports itself. |
-| pkg_ok/__init__.py:3:1:3:23 | Import | The module 'pkg_ok' imports itself. |
-| pkg_ok/__init__.py:4:1:4:28 | Import | The module 'pkg_ok' imports itself. |
-| pkg_ok/__init__.py:6:1:6:18 | Import | The module 'pkg_ok' imports itself. |
-| pkg_ok/__init__.py:7:1:7:22 | Import | The module 'pkg_ok' imports itself. |

python/ql/test/query-tests/Imports/PyCheckerTests/options

@@ -0,0 +1 @@
+semmle-extractor-options: --max-import-depth=2

python/ql/test/query-tests/Imports/PyCheckerTests/pkg_ok/__init__.py

@@ -1,7 +1,7 @@
-import pkg_ok.foo1 as foo1 # TODO: FP
+import pkg_ok.foo1 as foo1
 
-from pkg_ok import foo2 # TODO: FP
-from pkg_ok.foo3 import Foo3 # TODO: FP
+from pkg_ok import foo2
+from pkg_ok.foo3 import Foo3
 
-from . import foo4 # TODO: FP
-from .foo5 import Foo5 # TODO: FP
+from . import foo4
+from .foo5 import Foo5