[ADD] ocabot migration issue maintainer

New ocabot command for maintaining migration issues:

``/ocabot migration``, followed by the module name, performing the following:

* Look for an issue in that repository with the name "Migration to version
  ``{version}``", where ``{version}`` is the name of the target branch.
* Add or edit a line in that issue, linking the module to the pull request
  (PR) and the author of it.
* TODO: When the PR is merged, the line gets ticked.
* Put the milestone corresponding to the target branch in the PR.

Co-authored-by: Pedro M. Baeza <[email protected]>

Author: joao-p-marques

Diff for: README.rst

@@ -89,6 +89,15 @@ can be used to ask the bot to do the following:
 
 * rebase the PR on the target branch
 
+``/ocabot migration``, followed by the module name, performing the following:
+
+* Look for an issue in that repository with the name "Migration to version
+  ``{version}``", where ``{version}`` is the name of the target branch.
+* Add or edit a line in that issue, linking the module to the pull request
+  (PR) and the author of it.
+* TODO: When the PR is merged, the line gets ticked.
+* Put the milestone corresponding to the target branch in the PR.
+
 TODO (help wanted)
 ------------------
 
@@ -215,6 +224,8 @@ Contributors
 * Jose Angel Fentanez <[email protected]>
 * Simone Rubino <[email protected]>
 * Sylvain Le Gal (https://twitter.com/legalsylvain)
+* Tecnativa - Pedro M. Baeza
+* Tecnativa - Víctor Martínez
 
 Maintainers
 ===========

Diff for: src/oca_github_bot/commands.py

@@ -3,7 +3,7 @@
 
 import re
 
-from .tasks import merge_bot, rebase_bot
+from .tasks import merge_bot, migration_issue_bot, rebase_bot
 
 BOT_COMMAND_RE = re.compile(
     # Do not start with > (Github comment), not consuming it
@@ -61,6 +61,8 @@ def create(cls, name, options):
             return BotCommandMerge(name, options)
         elif name == "rebase":
             return BotCommandRebase(name, options)
+        elif name == "migration":
+            return BotCommandMigrationIssue(name, options)
         else:
             raise InvalidCommandError(name)
 
@@ -102,6 +104,21 @@ def delay(self, org, repo, pr, username, dry_run=False):
         rebase_bot.rebase_bot_start.delay(org, repo, pr, username, dry_run=False)
 
 
+class BotCommandMigrationIssue(BotCommand):
+    module = None  # mandatory str: module name
+
+    def parse_options(self, options):
+        if len(options) == 1:
+            self.module = options[0]
+        else:
+            raise InvalidOptionsError(self.name, options)
+
+    def delay(self, org, repo, pr, username, dry_run=False):
+        migration_issue_bot.migration_issue_start.delay(
+            org, repo, pr, username, module=self.module, dry_run=dry_run
+        )
+
+
 def parse_commands(text):
     """ Parse a text and return an iterator of BotCommand objects. """
     for mo in BOT_COMMAND_RE.finditer(text):

Diff for: src/oca_github_bot/config.py

@@ -54,6 +54,12 @@ def func_wrapper(*args, **kwargs):
 
 DRY_RUN = os.environ.get("DRY_RUN", "").lower() in ("1", "true", "yes")
 
+# Coma separated list of task to run
+# By default all configured tasks are run.
+# Available tasks:
+#  delete_branch,tag_approved,tag_ready_to_merge,gen_addons_table,
+#  gen_addons_readme,gen_addons_icon,setuptools_odoo,merge_bot,tag_needs_review,
+#  migration_issue_bot
 BOT_TASKS = os.environ.get("BOT_TASKS", "all").split(",")
 
 BOT_TASKS_DISABLED = os.environ.get("BOT_TASKS_DISABLED", "").split(",")

Diff for: src/oca_github_bot/tasks/__init__.py

@@ -5,6 +5,7 @@
     heartbeat,
     main_branch_bot,
     mention_maintainer,
+    migration_issue_bot,
     tag_approved,
     tag_needs_review,
     tag_ready_to_merge,

Diff for: src/oca_github_bot/tasks/migration_issue_bot.py

@@ -0,0 +1,115 @@
+# Copyright 2019 Tecnativa - Pedro M. Baeza
+# Copyright 2021 Tecnativa - Víctor Martínez
+# Distributed under the MIT License (http://opensource.org/licenses/MIT).
+
+import re
+
+from .. import github
+from ..config import switchable
+from ..process import check_call
+from ..queue import getLogger, task
+from ..manifest import user_can_push
+
+_logger = getLogger(__name__)
+
+
+def _create_or_find_branch_milestone(repo, branch):
+    for milestone in repo.milestones():
+        if milestone.title == branch:
+            return milestone
+    return repo.create_milestone(branch)
+
+
+def _find_issue(repo, milestone, target_branch):
+    issue_title = f"Migration to version {target_branch}"
+    issue = False
+    for i in repo.issues(milestone=milestone.number):
+        if i.title == issue_title:
+            issue = i
+            break
+    return issue
+
+
+def _set_lines_issue(gh_pr, issue, module):
+    lines = []
+    added = False
+    module_list = False
+    new_line = f"- [ ] {module} - By @{gh_pr.user.login} - #{gh_pr.number}"
+    for line in issue.body.split("\n"):
+        if line.startswith(f"- [ ] {module}"):
+            lines.append(new_line)
+            continue
+        elif not added:
+            splits = re.split(r"- \[ \] ([0-9a-zA-Z_]*)", line)
+            if len(splits) >= 2:
+                # Flag for detecting if we have passed already module list
+                module_list = True
+                line_module = splits[1]
+                if line_module > module:
+                    lines.append(new_line)
+                    added = True
+            elif module_list:
+                lines.append(new_line)
+                added = True
+        lines.append(line)
+    return lines
+
+
+@task()
+@switchable("migration_issue_bot")
+def migration_issue_start(org, repo, pr, username, module=None, dry_run=False):
+    with github.login() as gh:
+        gh_pr = gh.pull_request(org, repo, pr)
+        target_branch = gh_pr.base.ref
+        pr_branch = f"tmp-pr-{pr}"
+        try:
+            with github.temporary_clone(org, repo, target_branch) as clone_dir:
+                # Create merge bot branch from PR and rebase it on target branch
+                # This only serves for checking permissions
+                check_call(
+                    ["git", "fetch", "origin", f"pull/{pr}/head:{pr_branch}"],
+                    cwd=clone_dir,
+                )
+                check_call(["git", "checkout", pr_branch], cwd=clone_dir)
+                if not _user_can_push(
+                    gh, org, repo, username, clone_dir, target_branch
+                ):
+                    github.gh_call(
+                        gh_pr.create_comment,
+                        f"Sorry @{username} you are not allowed to mark the addon to"
+                        f"be migrated.\n\n"
+                        f"To do so you must either have push permissions on "
+                        f"the repository, or be a declared maintainer of all "
+                        f"modified addons.\n\n"
+                        f"If you wish to adopt an addon and become it's "
+                        f"[maintainer]"
+                        f"(https://odoo-community.org/page/maintainer-role), "
+                        f"open a pull request to add "
+                        f"your GitHub login to the `maintainers` key of its "
+                        f"manifest.",
+                    )
+                    return
+            # Assign milestone to PR
+            milestone = _create_or_find_branch_milestone(repo, target_branch)
+            gh_pr.issue().edit(milestone=milestone.number)
+            # Find issue
+            issue = _find_issue(repo, milestone, target_branch)
+            if not issue:
+                issue_title = f"Migration to version {target_branch}"
+                github.gh_call(
+                    gh_pr.create_comment,
+                    f"There's no issue in this repo with the title '{issue_title}' "
+                    f"and the milestone {target_branch}, so not possible to add "
+                    f"the comment.",
+                )
+                return
+            # Change issue to add the PR in the module list
+            lines = _set_lines_issue(gh_pr, issue, module)
+            issue.edit(body="\n".join(lines))
+        except Exception as e:
+            github.gh_call(
+                gh_pr.create_comment,
+                f"@{username} The migration issue commenter process could not "
+                f"start, because of exception {e}.",
+            )
+            raise