Audit script to find potentially broken for loops.

misc/python3/audit-dict-for-loops.py

@@ -0,0 +1,43 @@
+"""
+The following code is valid in Python 2:
+
+for x in my_dict.keys():
+    if something(x):
+        del my_dict[x]
+
+But broken in Python 3.
+
+One solution is:
+
+for x in list(my_dict.keys()):
+    if something(x):
+        del my_dict[x]
+
+Some but not all code in Tahoe has been changed to that. In other cases, the code was left unchanged since there was no `del`.
+
+However, some mistakes may have slept through.
+
+To help catch cases that were incorrectly ported, this script runs futurize on all ported modules, which should convert it into the `list()` form.
+You can then look at git diffs to see if any of the impacted would be buggy without the newly added `list()`.
+"""
+
+import os
+from subprocess import check_call
+
+from allmydata.util import _python3
+
+
+def fix_potential_issue():
+    for module in _python3.PORTED_MODULES + _python3.PORTED_TEST_MODULES:
+        filename = "src/" + module.replace(".", "/") + ".py"
+        if not os.path.exists(filename):
+            # Package, probably
+            filename = "src/" + module.replace(".", "/") + "/__init__.py"
+        check_call(["futurize", "-f", "lib2to3.fixes.fix_dict", "-w", filename])
+    print(
+        "All loops converted. Check diff to see if there are any that need to be commitedd."
+    )
+
+
+if __name__ == "__main__":
+    fix_potential_issue()