my.fbmessenger: move fbmessenger.py into fbmessenger/export.py

keeping it backwards compatible + conditional warning similar to #179

follow up for purarue/HPI#18
for now without the __path__ hacking, will do it in bulk later

too lazy to run test_import_warnings.sh on CI for now, but figured I'd commit it for the reference anyway

my/fbmessenger/__init__.py

@@ -0,0 +1,58 @@
+"""
+This is here temporarily, for backwards compatibility purposes
+It should be removed in the future, and you should replace any imports
+like:
+from my.fbmessenger import ...
+to:
+from my.fbmessenger.export import ...
+since that allows for easier overriding using namespace packages
+https://github.com/karlicoss/HPI/issues/102
+"""
+# TODO ^^ later, replace the above with from my.fbmessenger.all, when we add more data sources
+
+# For now, including this here, since importing the module
+# causes .export to be imported, which requires fbmessengerexport
+REQUIRES = [
+    'git+https://github.com/karlicoss/fbmessengerexport',
+]
+
+import re
+import inspect
+
+
+mname = 'fbmessenger'  # todo infer from __name__?
+
+
+# allow stuff like 'import my.module.submodule' and such
+imported_as_parent = False
+
+
+# allow stuff like 'from my.module import submodule'
+importing_submodule = False
+
+# some hacky traceback to inspect the current stack
+# to see if the user is using the old style of importing
+for f in inspect.stack():
+    # seems that when a submodule is imported, at some point it'll call some internal import machinery
+    # with 'parent' set to the parent module
+    # if parent module is imported first (i.e. in case of deprecated usage), it won't be the case
+    args = inspect.getargvalues(f.frame)
+    if args.locals.get('parent') == f'my.{mname}':
+        imported_as_parent = True
+
+    # this we can only detect from the code I guess
+    line = '\n'.join(f.code_context or [])
+    if re.match(rf'from\s+my\.{mname}\s+import\s+export', line):
+        # todo 'export' is hardcoded, not sure how to infer allowed objects anutomatically..
+        importing_submodule = True
+
+
+warn = not (imported_as_parent or importing_submodule)
+
+# TODO: add link to instructions to migrate
+if warn:
+    from my.core import warnings as W
+    W.high("DEPRECATED! Instead of my.fbmessengerexport, import from my.fbmessengerexport.export")
+
+
+from .export import *

my/fbmessenger.py → my/fbmessenger/export.py

@@ -10,11 +10,12 @@
 from pathlib import Path
 from typing import Iterator
 
-from .core import PathIsh
+from ..core import PathIsh
 
 import fbmessengerexport.dal as messenger
 
 from my.config import fbmessenger as config
+# TODO migrate this config to my.fbmessenger.export
 
 
 def _dal() -> messenger.DAL:
@@ -28,7 +29,7 @@ def messages() -> Iterator[messenger.Message]:
         yield from t.iter_messages()
 
 
-from .core import stat, Stats
+from ..core import stat, Stats
 def stats() -> Stats:
     return stat(messages)
 

tests/test_import_warnings.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+set -eu
+
+errors=0
+function expect_warn () {
+    echo "check: " "$@"
+    [[ $(2>&1 "$@" | grep -c DEPRECATED) -gt 0 ]] || {
+        echo "ERROR: " "$@"
+        errors=1
+    }
+}
+
+function expect_ok () {
+    echo "check: " "$@"
+    [[ $(2>&1 "$@" | grep -c DEPRECATED) -eq 0 ]] || {
+        echo "ERROR: " "$@"
+        errors=1
+    }
+}
+
+
+# TODO actually this one might be ok? nothing wrong with it in principle
+expect_warn python3 -c 'from   my import fbmessenger'
+echo                   'from   my import fbmessenger' > /tmp/script.py
+expect_warn python3 /tmp/script.py
+
+expect_warn python3 -c 'from   my.fbmessenger import messages'
+echo                   'from   my.fbmessenger import messages' > /tmp/script.py
+expect_warn python3 /tmp/script.py
+
+expect_warn python3 -c 'from   my.fbmessenger import *'
+echo                   'from   my.fbmessenger import *' > /tmp/script.py
+expect_warn python3 /tmp/script.py
+
+expect_warn python3 -c 'import my.fbmessenger'
+echo                   'import my.fbmessenger' > /tmp/script.py
+expect_warn python3 /tmp/script.py
+
+expect_warn python3 -m my.core query  my.fbmessenger.messages
+expect_warn python3 -m my.core doctor my.fbmessenger
+
+
+expect_ok   python3 -c 'from   my.fbmessenger.export import *'
+echo                   'from   my.fbmessenger.export import *' > /tmp/script.py
+expect_ok   python3 /tmp/script.py
+
+
+# TODO kinda annoying: this doesn't work, and doesn't seem like traceback has anything
+# guess it's fine, kind of a border case
+# expect_ok   python3 -c 'from   my.fbmessenger import export'
+echo                   'from   my.fbmessenger import export' > /tmp/script.py
+expect_ok   python3 /tmp/script.py
+
+expect_ok   python3 -c 'import my.fbmessenger.export'
+echo                   'import my.fbmessenger.export' > /tmp/script.py
+expect_ok   python3 /tmp/script.py
+
+expect_ok   python3 -m my.core query  my.fbmessenger.export.messages
+expect_ok   python3 -m my.core doctor my.fbmessenger.export
+
+
+exit $errors