From a5b1ac5c4cc620d5ae7a7432d5efcce818f8cc4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emmanuel=20Beno=C3=AEt?= <tseeker@nocternity.net>
Date: Sun, 4 Sep 2022 22:54:03 +0200
Subject: [PATCH] Better loop variable state handling

  * Loops caused local scripts variables to be backed up then restored,
    which would have caused a set_var in a loop to have no effect.
  * Instead, we back up the state of the variable (existing or not,
    value) and either restore the original value or delete the variable
    if it didn't exist.
---
 inventory_plugins/reconstructed.py | 34 +++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/inventory_plugins/reconstructed.py b/inventory_plugins/reconstructed.py
index a06ef35..395a243 100644
--- a/inventory_plugins/reconstructed.py
+++ b/inventory_plugins/reconstructed.py
@@ -220,18 +220,28 @@ class RcInstruction(abc.ABC):
         if self._loop is None:
             self._display.vvvv("%s : running action %s" % (host_name, self._action))
             return self.run_once(host_name, merged_vars, host_vars, script_vars)
-        loop_values = self.evaluate_loop(host_name, merged_vars)
-        script_vars = script_vars.copy()
-        for value in loop_values:
-            self._display.vvvv(
-                "%s : running action %s for item %s"
-                % (host_name, self._action, repr(value))
-            )
-            merged_vars[self._loop_var] = value
-            script_vars[self._loop_var] = value
-            if not self.run_once(host_name, merged_vars, host_vars, script_vars):
-                return False
-        return True
+        # Save previous loop variable state
+        had_loop_var = self._loop_var in script_vars
+        if had_loop_var:
+            old_loop_var = script_vars[self._loop_var]
+        try:
+            # Loop over all values
+            for value in self.evaluate_loop(host_name, merged_vars):
+                self._display.vvvv(
+                    "%s : running action %s for item %s"
+                    % (host_name, self._action, repr(value))
+                )
+                merged_vars[self._loop_var] = value
+                script_vars[self._loop_var] = value
+                if not self.run_once(host_name, merged_vars, host_vars, script_vars):
+                    return False
+            return True
+        finally:
+            # Restore loop variable state
+            if had_loop_var:
+                script_vars[self._loop_var] = old_loop_var
+            else:
+                del script_vars[self._loop_var]
 
     def run_once(self, host_name, merged_vars, host_vars, script_vars):
         if self.evaluate_condition(host_name, merged_vars):