Add a "create a similar rollup" link in rollup PR body

cfg.production.toml

@@ -18,6 +18,7 @@ ${HOMU_SSH_KEY}
 host = '0.0.0.0'
 port = 80
 
+base_url = "https://bors.rust-lang.org"
 canonical_url = "https://bors.rust-lang.org"
 remove_path_prefixes = ["homu"]
 

cfg.sample.toml

@@ -51,6 +51,12 @@ port = 54856
 # all open PRs.
 sync_on_start = true
 
+# The base url used for links pointing to this homu instance.
+# If base_url is not present, links will use canonical_url as a fallback.
+# If neither base_url nor canonical_url are present, no links to this homu
+# instance will be generated.
+#base_url = "https://bors.example.com"
+
 # The canonical URL of this homu instance. If a user reaches the instance
 # through a different path they will be redirected. If this is not present in
 # the configuration homu will still work, but no redirect will be performed.

homu/html/queue.html

@@ -187,9 +187,14 @@ <h1>Homu queue - {% if repo_url %}<a href="{{repo_url}}" target="_blank">{{repo_
 
             <tbody>
                 {% for state in states %}
+                {% set checkbox_state =
+                    ('checked' if state.prechecked else '') if
+                        ((state.status == 'approved' or (state.status == 'pending' and not state.try_)) and state.rollup != 'never')
+                    else 'disabled'
+                %}
                 <tr class="{{state.greyed}}">
                     <td class="hide">{{loop.index}}</td>
-                    <td><input type="checkbox" data-num="{{state.num}}" {{ '' if ((state.status == 'approved' or (state.status == 'pending' and not state.try_)) and state.rollup != 'never') else 'disabled' }}></td>
+                    <td><input type="checkbox" data-num="{{state.num}}" {{checkbox_state}}></td>
                     {% if multiple %}
                     <td><a href="{{state.repo_url}}">{{state.repo_label}}</a></td>
                     {% endif %}

homu/main.py

@@ -41,6 +41,15 @@
 
 VARIABLES_RE = re.compile(r'\${([a-zA-Z_]+)}')
 
+IGNORE_BLOCK_START = '<!-- homu-ignore:start -->'
+IGNORE_BLOCK_END = '<!-- homu-ignore:end -->'
+IGNORE_BLOCK_RE = re.compile(
+                    r'<!--\s*homu-ignore:start\s*-->'
+                    r'.*'
+                    r'<!--\s*homu-ignore:end\s*-->',
+                    flags=re.MULTILINE | re.DOTALL | re.IGNORECASE
+                )
+
 global_cfg = {}
 
 
@@ -50,6 +59,12 @@ def suppress_pings(text):
     return re.sub(r'\B(@\S+)', r'`\g<1>`', text)  # noqa
 
 
+# Replace any text between IGNORE_BLOCK_START and IGNORE_BLOCK_END
+# HTML comments with an empty string in merge commits
+def suppress_ignore_block(text):
+    return IGNORE_BLOCK_RE.sub('', text)
+
+
 @contextmanager
 def buildbot_sess(repo_cfg):
     sess = requests.Session()
@@ -356,6 +371,7 @@ def refresh(self):
 
         self.title = issue.title
         self.body = suppress_pings(issue.body)
+        self.body = suppress_ignore_block(self.body)
 
     def fake_merge(self, repo_cfg):
         if not repo_cfg.get('linear', False):
@@ -1554,6 +1570,7 @@ def synchronize(repo_label, repo_cfg, logger, gh, states, repos, db, mergeable_q
         state = PullReqState(pull.number, pull.head.sha, status, db, repo_label, mergeable_que, gh, repo_cfg['owner'], repo_cfg['name'], repo_cfg.get('labels', {}), repos, repo_cfg.get('test-on-fork'))  # noqa
         state.title = pull.title
         state.body = suppress_pings(pull.body)
+        state.body = suppress_ignore_block(state.body)
         state.head_ref = pull.head.repo[0] + ':' + pull.head.ref
         state.base_ref = pull.base.ref
         state.set_mergeable(None)

homu/server.py

@@ -5,7 +5,11 @@
     PullReqState,
     parse_commands,
     db_query,
+    IGNORE_BLOCK_END,
+    IGNORE_BLOCK_START,
     INTERRUPTED_BY_HOMU_RE,
+    suppress_ignore_block,
+    suppress_pings,
     synchronize,
     LabelEvent,
 )
@@ -139,6 +143,10 @@ def queue(repo_label):
         except KeyError:
             abort(404, 'No such repository: {}'.format(label))
 
+    prechecked_prs = set()
+    if request.query.get('prs'):
+        prechecked_prs = set(request.query.get('prs').split(','))
+
     pull_states = sorted(states)
     rows = []
     for state in pull_states:
@@ -154,6 +162,7 @@ def queue(repo_label):
             'status_ext': status_ext,
             'priority': state.priority,
             'rollup': ROLLUP_STR.get(state.rollup, ''),
+            'prechecked': str(state.num) in prechecked_prs,
             'url': 'https://github.com/{}/{}/pull/{}'.format(state.owner,
                                                              state.name,
                                                              state.num),
@@ -301,6 +310,9 @@ def rollup(user_gh, state, repo_label, repo_cfg, repo):
             failures.append(state.num)
             continue
 
+        state.body = suppress_pings(state.body)
+        state.body = suppress_ignore_block(state.body)
+
         merge_msg = 'Rollup merge of #{} - {}, r={}\n\n{}\n\n{}'.format(
             state.num,
             state.head_ref,
@@ -329,6 +341,20 @@ def rollup(user_gh, state, repo_label, repo_cfg, repo):
         body += ' - #{} ({})\n'.format(x.num, x.title)
     body += '\nr? @ghost'
 
+    # Set web.base_url in cfg to enable
+    base_url = g.cfg['web'].get('base_url')
+    if not base_url:
+        # If web.base_url is not present, fall back to using web.canonical_url
+        base_url = g.cfg['web'].get('canonical_url')
+
+    if base_url:
+        pr_list = ','.join(str(x.num) for x in successes)
+        link = '{}/queue/{}?prs={}'.format(base_url, repo_label, pr_list)
+        body += '\n'
+        body += IGNORE_BLOCK_START
+        body += '\n[Create a similar rollup]({})\n'.format(link)
+        body += IGNORE_BLOCK_END
+
     try:
         pull = base_repo.create_pull(
             title,

homu/tests/test_pr_body.py

@@ -1,4 +1,9 @@
-from homu.main import suppress_pings
+from homu.main import (
+    suppress_ignore_block,
+    suppress_pings,
+    IGNORE_BLOCK_START,
+    IGNORE_BLOCK_END,
+)
 
 
 def test_suppress_pings_in_PR_body():
@@ -15,3 +20,18 @@ def test_suppress_pings_in_PR_body():
     )
 
     assert suppress_pings(body) == expect
+
+
+def test_suppress_ignore_block_in_PR_body():
+    body = (
+        "Rollup merge\n"
+        "{}\n"
+        "[Create a similar rollup](https://fake.xyz/?prs=1,2,3)\n"
+        "{}"
+    )
+
+    body = body.format(IGNORE_BLOCK_START, IGNORE_BLOCK_END)
+
+    expect = "Rollup merge\n"
+
+    assert suppress_ignore_block(body) == expect