Bug 1747280 - nuke comm/ after cross-channel. r=mhentges,releng-reviewers,jmaher DONTBUILD

We clean up our Gecko clone between tasks via `hg robustcheckout --purge`, which runs `hg purge`. This is very effective, *but* it doesn't detect or clean up any nested clones.

Because we run cross-channel on Gecko workers, and because we clone `comm/` in cross-channel and haven't cleaned it up, and because `hg purge` doesn't detect or clean up nested clones, and because our current virtualenv setup code traverses the tree and can error out on `comm/` clones, let's clean up `comm/` after running cross-channel.

We'll be moving TB cross-channel to different tasks/workers in bug 1742711, and ideally we can update robustcheckout and/or `hg purge` to be able to detect and/or clean up nested clones.

Differential Revision: https://phabricator.services.mozilla.com/D134582

python/l10n/mozxchannel/__init__.py

@@ -48,6 +48,7 @@ def get_default_config(topsrcdir, strings_path):
             },
             "comm-central": {
                 "path": topsrcdir / "comm",
+                "post-clobber": True,
                 "url": "https://hg.mozilla.org/comm-central/",
                 "heads": {
                     # This list of repositories is ordered, starting with the

taskcluster/ci/l10n-cross-channel/kind.yml

@@ -37,5 +37,5 @@ jobs:
             using: mach
             actions:
                 by-level:
-                    "3": ["prep", "create", "push"]
-                    default: ["prep", "create"]
+                    "3": ["prep", "create", "push", "clean"]
+                    default: ["prep", "create", "clean"]

tools/compare-locales/mach_commands.py

@@ -146,7 +146,7 @@ HGRC_PATH = Path(user_config_dir("hg")).joinpath("hgrc")
 )
 @CommandArgument(
     "actions",
-    choices=("prep", "create", "push"),
+    choices=("prep", "create", "push", "clean"),
     nargs="+",
     # This help block will be poorly formatted until we fix bug 1714239
     help="""
@@ -154,6 +154,7 @@ HGRC_PATH = Path(user_config_dir("hg")).joinpath("hgrc")
     "create": create the en-US strings commit an optionally create an
               outgoing() patch.
     "push": push the en-US strings to the quarantine repo.
+    "clean": clean up any sub-repos.
     """,
 )
 def cross_channel(
@@ -318,6 +319,11 @@ def _do_create_content(
         else:
             command_context.log(logging.INFO, "push", {}, "Skipping empty push.")
 
+    if "clean" in actions:
+        for repo_config in config.get("source", {}).values():
+            if repo_config.get("post-clobber", False):
+                _nuke_hg_repo(command_context, str(repo_config["path"]))
+
     return status
 
 
@@ -397,3 +403,7 @@ def _check_hg_repo(command_context, path, heads=None):
 
 def _clone_hg_repo(command_context, url, path):
     _retry_run_process(command_context, ["hg", "clone", url, str(path)])
+
+
+def _nuke_hg_repo(command_context, path):
+    _retry_run_process(command_context, ["rm", "-rf", str(path)])