[IMP] forwardport: improve disable fp UI

* always allow specifying the PR's own branch as a forward-port limit
  / target (even if deactivated or disabled)
* add an "ignore" alias to "up to <pr target>" for clarity
* add dedicated feedback when deactivating forward-port of a PR

Fixes #191

forwardport/models/project.py

@@ -188,7 +188,15 @@ class PullRequests(models.Model):
 
         # TODO: don't use a mutable tokens iterator
         tokens = iter(tokens)
-        for token in tokens:
+        while True:
+            token = next(tokens, None)
+            if token is None:
+                break
+
+            if token == 'ignore': # replace 'ignore' by 'up to <pr_branch>'
+                token = 'up'
+                tokens = itertools.chain(['to', self.target.name], tokens)
+
             if token in ('r+', 'review+') and self.source_id._pr_acl(author).is_reviewer:
                 # don't update the root ever
                 for pr in filter(lambda p: p.parent_id, self._iter_ancestors()):
@@ -208,12 +216,16 @@ class PullRequests(models.Model):
                     ])
                     if not limit_id:
                         msg = "There is no branch %r, it can't be used as a forward port target." % limit
+                    elif limit_id == self.target:
+                        msg = "Forward-port disabled."
+                        self.limit_id = limit_id
                     elif not limit_id.fp_enabled:
                         msg = "Branch %r is disabled, it can't be used as a forward port target." % limit_id.name
                     else:
                         msg = "Forward-porting to %r." % limit_id.name
                         self.limit_id = limit_id
 
+                _logger.info("%s: %s", author, msg)
                 self.env['runbot_merge.pull_requests.feedback'].create({
                     'repository': self.repository.id,
                     'pull_request': self.number,
@@ -221,6 +233,7 @@ class PullRequests(models.Model):
                     'token_field': 'fp_github_token',
                 })
 
+
     def _validate(self, statuses):
         _logger = logging.getLogger(__name__).getChild('forwardport.next')
         failed = super()._validate(statuses)

forwardport/tests/test_simple.py

@@ -761,6 +761,54 @@ def test_limit_configure(env, config, make_repo):
     assert prs[1].number == originals[1]
     assert prs[2].number == originals[2]
 
+def test_limit_self_disabled(env, config, make_repo):
+    """ Allow setting target as limit even if it's disabled
+    """
+    prod, other = make_basic(env, config, make_repo)
+    bot_name = env['runbot_merge.project'].search([]).fp_github_name
+    branch_a = env['runbot_merge.branch'].search([('name', '=', 'a')])
+    branch_a.fp_target = False
+    with prod:
+        [c] = prod.make_commits('a', Commit('c', tree={'0': '0'}), ref='heads/mybranch')
+        pr = prod.make_pr(target='a', head='mybranch')
+        prod.post_status(c, 'success', 'legal/cla')
+        prod.post_status(c, 'success', 'ci/runbot')
+        pr.post_comment('hansen r+\n%s up to a' % bot_name, config['role_reviewer']['token'])
+    env.run_crons()
+    pr_id = env['runbot_merge.pull_requests'].search([('number', '=', pr.number)])
+    assert pr_id.limit_id == branch_a
+
+    with prod:
+        prod.post_status('staging.a', 'success', 'legal/cla')
+        prod.post_status('staging.a', 'success', 'ci/runbot')
+
+    assert env['runbot_merge.pull_requests'].search([]) == pr_id,\
+        "should not have created a forward port"
+
+def test_fp_ignore(env, config, make_repo):
+    """ Provide an "ignore" command which is equivalent to setting the limit
+    to target
+    """
+    prod, other = make_basic(env, config, make_repo)
+    bot_name = env['runbot_merge.project'].search([]).fp_github_name
+    branch_a = env['runbot_merge.branch'].search([('name', '=', 'a')])
+    with prod:
+        [c] = prod.make_commits('a', Commit('c', tree={'0': '0'}), ref='heads/mybranch')
+        pr = prod.make_pr(target='a', head='mybranch')
+        prod.post_status(c, 'success', 'legal/cla')
+        prod.post_status(c, 'success', 'ci/runbot')
+        pr.post_comment('hansen r+\n%s ignore' % bot_name, config['role_reviewer']['token'])
+    env.run_crons()
+    pr_id = env['runbot_merge.pull_requests'].search([('number', '=', pr.number)])
+    assert pr_id.limit_id == branch_a
+
+    with prod:
+        prod.post_status('staging.a', 'success', 'legal/cla')
+        prod.post_status('staging.a', 'success', 'ci/runbot')
+
+    assert env['runbot_merge.pull_requests'].search([]) == pr_id,\
+        "should not have created a forward port"
+
 @pytest.mark.parametrize('enabled', ['active', 'fp_target'])
 def test_limit_disable(env, config, make_repo, users, enabled):
     """ Checks behaviour if the limit target is disabled: