ansible_mitogen: Allow mitogen_fetch to bypass slurp module

This reapplies an earlier change, when this plugin was first introduced to
Mitogen. The plugin was updated to fix

[DEPRECATION WARNING]: The '_remote_checksum()' method is deprecated.

I've elected to short-circuit the if statemtn logic, rather than
deleting/unindenting, to make the code delta much smaller. This should make it
easier to maintain/update.

Fixes #915

ansible_mitogen/plugins/action/mitogen_fetch.py

@@ -70,8 +70,8 @@ class ActionModule(ActionBase):
 
             remote_stat = {}
             remote_checksum = None
-            if not self._connection.become:
-                # Get checksum for the remote file. Don't bother if using become as slurp will be used.
+            if True:
+                # Get checksum for the remote file even using become. Mitogen doesn't need slurp.
                 # Follow symlinks because fetch always follows symlinks
                 try:
                     remote_stat = self._execute_remote_stat(source, all_vars=task_vars, follow=True)

docs/changelog.rst

@@ -25,6 +25,7 @@ v0.3.3.dev0
 * :gh:issue:`918` Support Python 3.10
 * :gh:issue:`920` Support Ansible :ans:conn:`~podman` connection plugin
 * :gh:issue:`836` :func:`mitogen.utils.with_router` decorator preserves the docstring in addition to the name.
+* :gh:issue:`936` :ans:mod:`fetch` no longer emits `[DEPRECATION WARNING]: The '_remote_checksum()' method is deprecated.`
 
 
 v0.3.2 (2022-01-12)

tests/ansible/regression/issue_615__streaming_transfer.yml

@@ -1,12 +1,14 @@
 # issue #615: 'fetch' with become: was internally using slurp.
 
-- hosts: target
+- hosts: test-targets
   any_errors_fatal: True
   gather_facts: no
+  # Without Mitogen this causes Ansible to use the slurp module, which is *slow*
   become: true
   vars:
     mitogen_ssh_compression: false
   tasks:
+    - block:
         - shell: |
             dd if=/dev/zero of=/tmp/512mb.zero bs=1048576 count=512;
             chmod go= /tmp/512mb.zero
@@ -15,9 +17,16 @@
             src: /tmp/512mb.zero
             dest: /tmp/fetch-out
 
+        - file:
+            path: /tmp/512mb.zero
+            state: absent
+
         - file:
             path: /tmp/fetch-out
             state: absent
           delegate_to: localhost
+          run_once: true
+      when:
+        - is_mitogen
   tags:
     - issue_615