[ADD] forwardport: views of outstanding forwardports

Though the forwardport posts regular reminders that an fw is outdated,
it can be easy to miss for the non-subject (and apparently the
subjects often just ignore the information entirely).

Add a few relevant links there:

* on PR pages, add a link to either the source or the
  forward-ports (if applicable), as well as the merge date
* add a new page which lists all the PRs with outstanding
  forwardports, as well as the forwardports in question

Fixes #474

forwardport/data/views.xml

@@ -6,6 +6,101 @@
                 Forward-port is disabled, merged pull requests will not be forward-ported.
             </div>
         </xpath>
+        <!-- key block (hopefully) -->
+        <xpath expr="//div[@id='alerts']" position="inside">
+            <t t-if="env['runbot_merge.pull_requests'].check_access_rights('read', False)">
+                <t t-set="outstanding" t-value="env['runbot_merge.pull_requests'].search_count([
+                    ('source_id', '!=', False),
+                    ('state', 'not in', ['merged', 'closed']),
+                ])"/>
+                <div t-if="outstanding != 0" class="alert col-md-12 bg-warning">
+                    <a href="/forwardport/outstanding">
+                        <t t-esc="outstanding"/> outstanding forward-ports
+                    </a>
+                </div>
+            </t>
+        </xpath>
+    </template>
+
+    <template id="pr_background">
+        <t t-if="p.state == 'merged'">bg-success</t>
+        <t t-elif="p.state == 'closed'">bg-light</t>
+        <t t-elif="p.state == 'error'">bg-danger</t>
+        <t t-else="">bg-warning</t>
+    </template>
+
+    <record id="forwardport.outstanding_fp" model="website.page">
+        <field name="name">Outstanding forward ports</field>
+        <field name="type">qweb</field>
+        <field name="url">/forwardport/outstanding</field>
+        <field name="website_indexed" eval="False"/>
+        <field name="is_published">True</field>
+        <field name="key">forwardport.outstanding_fp</field>
+        <field name="arch" type="xml">
+            <t name="Outstanding forward ports" t-name="forwardport.outstanding_fp">
+                <t t-call="website.layout">
+                    <div id="wrap" class="oe_structure oe_empty"><div class="container-fluid">
+                        <h1>List of pull requests with outstanding forward ports</h1>
+                        <dl><t t-foreach="env['runbot_merge.pull_requests']._outstanding()" t-as="x">
+                            <t t-set="source" t-value="x[0]"/>
+                            <t t-set="prs" t-value="x[1]"/>
+                            <dt>
+                                <a t-att-href="source.url"><span t-field="source.display_name"/></a>
+                                by <span t-field="source.author.display_name"
+                                         t-attf-title="@{{source.author.github_login}}"/>
+                                merged <span t-field="source.merge_date"
+                                             t-options="{'widget': 'relative'}"
+                                             t-att-title="source.merge_date"/>
+                                by <span t-field="source.reviewed_by.display_name"
+                                         t-attf-title="@{{source.reviewed_by.github_login}}"/>
+                            </dt>
+                            <dd>
+                                Outstanding forward-ports:
+                                <ul>
+                                    <li t-foreach="prs" t-as="p">
+                                        <a t-att-href="p.url"><span t-field="p.display_name"/></a>
+                                        (<span t-field="p.state"/>)
+                                        targeting <span t-field="p.target.name"/>
+                                    </li>
+                                </ul>
+                            </dd>
+                        </t></dl>
+                    </div></div>
+                </t>
+            </t>
+        </field>
+    </record>
+
+    <template id="view_pull_request" inherit_id="runbot_merge.view_pull_request">
+        <xpath expr="//dl[hasclass('runbot-merge-fields')]" position="inside">
+            <t t-if="pr.state == 'merged'">
+                <dt>merged</dt>
+                <dd>
+                    <span t-field="pr.merge_date" t-options="{'widget': 'relative'}"
+                          t-att-title="pr.merge_date"/>
+                </dd>
+            </t>
+            <t t-if="pr.source_id">
+                <dt>forward-port of</dt>
+                <dd>
+                    <a t-att-href="pr.source_id.url">
+                        <span t-field="pr.source_id.display_name"/>
+                    </a>
+                </dd>
+            </t>
+            <t t-if="pr.forwardport_ids">
+                <dt>forward-ports</dt>
+                <dd><ul>
+                    <t t-foreach="pr.forwardport_ids" t-as="p">
+                        <t t-set="bgsignal"><t t-call="forwardport.pr_background"/></t>
+                        <li t-att-class="bgsignal">
+                            <a t-att-href="p.url"><span t-field="p.display_name"/></a>
+                            targeting <span t-field="p.target.name"/>
+                        </li>
+                    </t>
+                </ul></dd>
+            </t>
+        </xpath>
     </template>
 
     <record model="ir.ui.view" id="project">

forwardport/models/project.py

@@ -34,7 +34,6 @@ from odoo.exceptions import UserError
 from odoo.tools import topological_sort, groupby
 from odoo.tools.appdirs import user_cache_dir
 from odoo.addons.runbot_merge import utils
-from odoo.addons.runbot_merge.models.pull_requests import RPLUS
 
 footer = '\nMore info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port\n'
 
@@ -192,6 +191,7 @@ class PullRequests(models.Model):
         help="a PR with a parent is an automatic forward port"
     )
     source_id = fields.Many2one('runbot_merge.pull_requests', index=True, help="the original source of this FP even if parents were detached along the way")
+    forwardport_ids = fields.One2many('runbot_merge.pull_requests', 'source_id')
     reminder_backoff_factor = fields.Integer(default=-4)
     merge_date = fields.Datetime()
 
@@ -1039,19 +1039,31 @@ stderr:
             repo.config('--add', 'remote.origin.fetch', '+refs/pull/*/head:refs/heads/pull/*')
             return repo
 
-    def _reminder(self):
+    def _outstanding(self, cutoff=None):
-        now = datetime.datetime.now()
+        """ Returns "outstanding" (unmerged and unclosed) forward-ports whose
-        cutoff = self.env.context.get('forwardport_updated_before') or fields.Datetime.to_string(now - DEFAULT_DELTA)
+        source was merged before ``cutoff`` (all of them if not provided).
-        cutoff_dt = fields.Datetime.from_string(cutoff)
 
-        for source, prs in groupby(self.env['runbot_merge.pull_requests'].search([
+        :param str cutoff: a datetime (ISO-8601 formatted)
+        :returns: an iterator of (source, forward_ports)
+        """
+        cutoff_terms = []
+        if cutoff:
+            # original merged more than <cutoff> ago
+            cutoff_terms = [('source_id.merge_date', '<', cutoff)]
+        return groupby(self.env['runbot_merge.pull_requests'].search([
             # only FP PRs
             ('source_id', '!=', False),
             # active
             ('state', 'not in', ['merged', 'closed']),
-            # original merged more than <cutoff> ago
+            *cutoff_terms,
-            ('source_id.merge_date', '<', cutoff),
+        ], order='source_id, id'), lambda p: p.source_id)
-        ], order='source_id, id'), lambda p: p.source_id):
+
+    def _reminder(self):
+        cutoff = self.env.context.get('forwardport_updated_before') \
+              or fields.Datetime.to_string(datetime.datetime.now() - DEFAULT_DELTA)
+        cutoff_dt = fields.Datetime.from_string(cutoff)
+
+        for source, prs in self._outstanding(cutoff):
             backoff = dateutil.relativedelta.relativedelta(days=2**source.reminder_backoff_factor)
             prs = list(prs)
             if source.merge_date > (cutoff_dt - backoff):