cargo: use the correct path when checking installation status fixing idempotency issue. (#7970)

* cargo: use the correct path when checking installation status

* Add changelog fragment

* Update changelogs/fragments/7970-fix-cargo-path-idempotency.yaml

Co-authored-by: Felix Fontein <felix@fontein.de>

---------

Co-authored-by: Felix Fontein <felix@fontein.de>

changelogs/fragments/7970-fix-cargo-path-idempotency.yaml

@@ -0,0 +1,10 @@
+bugfixes:
+  - "cargo - fix idempotency issues when using a custom installation path
+    for packages (using the ``--path`` parameter).
+    The initial installation runs fine, but subsequent runs use the
+    ``get_installed()`` function which did not check the given installation
+    location, before running ``cargo install``. This resulted in a false
+    ``changed`` state.
+    Also the removal of packeges using ``state: absent`` failed, as the
+    installation check did not use the given parameter
+    (https://github.com/ansible-collections/community.general/pull/7970)."

plugins/modules/cargo.py

@@ -137,6 +137,10 @@ class Cargo(object):
 
     def get_installed(self):
         cmd = ["install", "--list"]
+        if self.path:
+            cmd.append("--root")
+            cmd.append(self.path)
+
         data, dummy = self._exec(cmd, True, False, False)
 
         package_regex = re.compile(r"^([\w\-]+) v(.+):$")