[CHG] runbot_merge: switch staging from github API to local

It has been a consideration for a while, but the pain of subtly
interacting with git via the ignominous CLI kept it back. Then ~~the
fire nation attacked~~ github got more and more tight-fisted (and in
some ways less reliable) with their API.

Staging pretty much just interacts with the git database, so it's both
a facultative github operator (it can just interact with git directly)
and a big consumer of API requests (because the git database endpoints
are very low level so it takes quite a bit of work to do anything
especially when high-level operations like rebase have to be
replicated by hand).

Furthermore, an issue has also been noticed which can be attributed to
using the github API (and that API's reliability getting worse): in
some cases github will fail to propagate a ref update / reset, so when
staging 2 PRs it's possible that the second one is merged on top of
the temporary branch of the first one, yielding a kinda broken commit
(in that it's a merge commit with a broken error message) instead of
the rebase / squash commit we expected.

As it turns out it's a very old issue but only happened very early so
was misattributed and not (sufficiently) guarded against:

- 41bd82244bb976bbd4d4be5e7bd792417c7dae6b (October 8th 2018) was
  spotted but thought to be a mergebot issue (might have been one of
  the opportunities where ref-checks were added though I can't find
  any reference to the commit in the runbot repo).
- 2be25052e147b151d1d8a5bc73cceb351586ce03 (October 15th, 2019) was
  missed (or ignored).
- 5a9fe7a7d05a9df7186072a7bffd60c6b428fd0e (July 31st, 2023) was
  spotted, but happened at a moment where everything kinda broke
  because of github rate-limiting ref updates, so the forensics were
  difficult and it was attributed to rate limiting issues.
- f10d03bf0f2e8f88f62a5d8356b84f714196130f (August 24th, 2023) broke
  the camel's back (and the head block): the logs were not too
  interspersed with other garbage and pretty clear that github ack'd a
  ref update, returned the correct oid when checking the ref, then
  returned the wrong oid when fetching it later on.

No Working Copy
===============

The working copy turns out to not be necessary, the plumbing commands
we *need* work just fine on a bare repository.

Working without a WC means we had to reimplement the high level
operations (rebase) by hand much as we'd done previously, *but* we
needed to do that anyway as git doesn't seem to provide any way to
retrieve the mapping when rebasing/cherrypicking, and cherrypicking by
commit doesn't work well as it can't really find the *merge base* it
needs.

Forward-porting can almost certainly be implemented similarly (with
some overhead), issue #803 has been opened to keep track of the idea.

No TMP
======

The `tmp.` branches are no more, the process of creating stagings is
based entirely around oids, if staging something fails we can just
abandon the oids (they'll be collected by the weekly GC), we only
need to update the staging branches at the very end of the process.

This simplifies things a fair bit.

For now we have stopped checking for visibility / backoff as we're
pushing via git, hopefully it is a more reliable reference than the
API.

Commmit Message Formatting
==========================

There's some unfortunate churn in the test, as the handling of
trailing newlines differs between github's APIs and git itself.

Fixes #247

PS: It might be a good idea to use pygit2 instead of the CLI
    eventually, the library is typed which is nice, and it avoids
    shelling out although that's really unlikely to be a major cost.

conftest.py

@@ -537,6 +537,9 @@ class Repo:
         self.hook = False
         repos.append(self)
 
+    def __repr__(self):
+        return f'<conftest.Repo {self.name}>'
+
     @property
     def owner(self):
         return self.name.split('/')[0]

mergebot_test_utils/utils.py

@@ -8,7 +8,8 @@ MESSAGE_TEMPLATE = """{message}
 
 closes {repo}#{number}
 
-{headers}Signed-off-by: {name} <{email}>"""
+{headers}Signed-off-by: {name} <{email}>
+"""
 # target branch '-' source branch '-' base64 unique '-fw'
 REF_PATTERN = r'{target}-{source}-[a-zA-Z0-9_-]{{4}}-fw'
 
@@ -136,6 +137,4 @@ def to_pr(env, pr):
     return pr
 
 def part_of(label, pr_id, *, separator='\n\n'):
-    """ Adds the "part-of" pseudo-header in the footer.
-    """
-    return f'{label}{separator}Part-of: {pr_id.display_name}'
+    return f'{label}{separator}Part-of: {pr_id.display_name}\n'

runbot_merge/git.py

@@ -1,12 +1,14 @@
 import dataclasses
 import itertools
 import logging
+import os
 import pathlib
 import resource
 import subprocess
-from typing import Optional, TypeVar
+from typing import Optional, TypeVar, Union, Sequence, Tuple, Dict
 
 from odoo.tools.appdirs import user_cache_dir
+from .github import MergeError, PrCommit
 
 _logger = logging.getLogger(__name__)
 
@@ -17,6 +19,7 @@ def source_url(repository, prefix: str) -> str:
         repository.name,
     )
 
+Authorship = Union[Tuple[str, str], Tuple[str, str, str]]
 
 def get_local(repository, prefix: Optional[str]) -> 'Optional[Repo]':
     repos_dir = pathlib.Path(user_cache_dir('mergebot'))
@@ -104,6 +107,119 @@ class Repo:
         )
         return Repo(to)
 
+    def rebase(self, dest: str, commits: Sequence[PrCommit]) -> Tuple[str, Dict[str, str]]:
+        """Implements rebase by hand atop plumbing so:
+
+        - we can work without a working copy
+        - we can track individual commits (and store the mapping)
+
+        It looks like `--merge-base` is not sufficient for `merge-tree` to
+        correctly keep track of history, so it loses contents. Therefore
+        implement in two passes as in the github version.
+        """
+        repo = self.stdout().with_config(text=True, check=False)
+
+        logger = _logger.getChild('rebase')
+        logger.debug("rebasing %s on %s (reset=%s, commits=%s)",
+                     self._repo, dest, len(commits))
+        if not commits:
+            raise MergeError("PR has no commits")
+
+        new_trees = []
+        parent = dest
+        for original in commits:
+            if len(original['parents']) != 1:
+                raise MergeError(
+                    f"commits with multiple parents ({original['sha']}) can not be rebased, "
+                    "either fix the branch to remove merges or merge without "
+                    "rebasing")
+
+            new_trees.append(check(repo.merge_tree(parent, original['sha'])).stdout.strip())
+            parent = check(repo.commit_tree(
+                tree=new_trees[-1],
+                parents=[parent, original['sha']],
+                message=f'temp rebase {original["sha"]}',
+            )).stdout.strip()
+
+        mapping = {}
+        for original, tree in zip(commits, new_trees):
+            authorship = check(repo.show('--no-patch', '--pretty="%an%n%ae%n%ai%n%cn%n%ce"', original['sha']))
+            author_name, author_email, author_date, committer_name, committer_email =\
+                authorship.stdout.splitlines()
+
+            c = check(repo.commit_tree(
+                tree=tree,
+                parents=[dest],
+                message=original['commit']['message'],
+                author=(author_name, author_email, author_date),
+                committer=(committer_name, committer_email),
+            )).stdout.strip()
+
+            logger.debug('copied %s to %s (parent: %s)', original['sha'], c, dest)
+            dest = mapping[original['sha']] = c
+
+        return dest, mapping
+
+    def merge(self, c1: str, c2: str, msg: str, *, author: Tuple[str, str]) -> str:
+        repo = self.stdout().with_config(text=True, check=False)
+
+        t = repo.merge_tree(c1, c2)
+        if t.returncode:
+            raise MergeError(t.stderr)
+
+        c = self.commit_tree(
+            tree=t.stdout.strip(),
+            message=msg,
+            parents=[c1, c2],
+            author=author,
+        )
+        if c.returncode:
+            raise MergeError(c.stderr)
+        return c.stdout.strip()
+
+    def commit_tree(
+        self, *, tree: str, message: str,
+        parents: Sequence[str] = (),
+        author: Optional[Authorship] = None,
+        committer: Optional[Authorship] = None,
+    ) -> subprocess.CompletedProcess:
+        authorship = {}
+        if author:
+            authorship['GIT_AUTHOR_NAME'] = author[0]
+            authorship['GIT_AUTHOR_EMAIL'] = author[1]
+            if len(author) > 2:
+                authorship['GIT_AUTHOR_DATE'] = author[2]
+        if committer:
+            authorship['GIT_COMMITTER_NAME'] = committer[0]
+            authorship['GIT_COMMITTER_EMAIL'] = committer[1]
+            if len(committer) > 2:
+                authorship['GIT_COMMITTER_DATE'] = committer[2]
+
+        return self.with_config(
+            stdout=subprocess.PIPE,
+            text=True,
+            env={
+                **os.environ,
+                **authorship,
+                # we don't want git to use the timezone of the machine it's
+                # running on: previously it used the timezone configured in
+                # github (?), which I think / assume defaults to a generic UTC
+                'TZ': 'UTC',
+            }
+        )._run(
+            'commit-tree',
+            tree,
+            '-m', message,
+            *itertools.chain.from_iterable(('-p', p) for p in parents),
+        )
+
+def check(p: subprocess.CompletedProcess) -> subprocess.CompletedProcess:
+    if not p.returncode:
+        return p
+
+    _logger.info("rebase failed at %s\nstdout:\n%s\nstderr:\n%s", p.args, p.stdout, p.stderr)
+    raise MergeError(p.stderr or 'merge conflict')
+
 
 @dataclasses.dataclass
 class GitCommand:

runbot_merge/models/stagings_create.py

@@ -6,10 +6,9 @@ import json
 import logging
 import os
 import re
-import tempfile
 from difflib import Differ
-from itertools import count, takewhile
-from pathlib import Path
+from itertools import takewhile
+from operator import itemgetter
 from typing import Dict, Union, Optional, Literal, Callable, Iterator, Tuple, List, TypeAlias
 
 import requests
@@ -17,7 +16,6 @@ from werkzeug.datastructures import Headers
 
 from odoo import api, models, fields
 from odoo.tools import OrderedSet
-from odoo.tools.appdirs import user_cache_dir
 from .pull_requests import Branch, Stagings, PullRequests, Repository, Batch
 from .. import exceptions, utils, github, git
 
@@ -40,7 +38,7 @@ class StagingSlice:
     """
     gh: github.GH
     head: str
-    working_copy: git.Repo
+    repo: git.Repo
 
 
 StagingState: TypeAlias = Dict[Repository, StagingSlice]
@@ -82,43 +80,7 @@ def try_staging(branch: Branch) -> Optional[Stagings]:
     else: # p=2
         batched_prs = [pr_ids for _, pr_ids in takewhile(lambda r: r[0] == priority, rows)]
 
-    with contextlib.ExitStack() as cleanup:
-        return stage_into(branch, batched_prs, cleanup)
-
-
-def ready_prs(for_branch: Branch) -> List[Tuple[int, PullRequests]]:
-    env = for_branch.env
-    env.cr.execute("""
-    SELECT
-      min(pr.priority) as priority,
-      array_agg(pr.id) AS match
-    FROM runbot_merge_pull_requests pr
-    WHERE pr.target = any(%s)
-      -- exclude terminal states (so there's no issue when
-      -- deleting branches & reusing labels)
-      AND pr.state != 'merged'
-      AND pr.state != 'closed'
-    GROUP BY
-        pr.target,
-        CASE
-            WHEN pr.label SIMILAR TO '%%:patch-[[:digit:]]+'
-                THEN pr.id::text
-            ELSE pr.label
-        END
-    HAVING
-        bool_or(pr.state = 'ready') or bool_or(pr.priority = 0)
-    ORDER BY min(pr.priority), min(pr.id)
-    """, [for_branch.ids])
-    browse = env['runbot_merge.pull_requests'].browse
-    return [(p, browse(ids)) for p, ids in env.cr.fetchall()]
-
-
-def stage_into(
-        branch: Branch,
-        batched_prs: List[PullRequests],
-        cleanup: contextlib.ExitStack,
-) -> Optional[Stagings]:
-    original_heads, staging_state = staging_setup(branch, batched_prs, cleanup)
+    original_heads, staging_state = staging_setup(branch, batched_prs)
 
     staged = stage_batches(branch, batched_prs, staging_state)
 
@@ -146,18 +108,22 @@ def stage_into(
             # (with a uniquifier to ensure we don't hit a previous version of
             # the same) to ensure the staging head is new and we're building
             # everything
-            tree = it.gh.commit(it.head)['tree']
+            project = branch.project_id
             uniquifier = base64.b64encode(os.urandom(12)).decode('ascii')
-            dummy_head = it.gh('post', 'git/commits', json={
-                'tree': tree['sha'],
-                'parents': [it.head],
-                'message': f'''\
+            dummy_head = it.repo.with_config(check=True).commit_tree(
+                # somewhat exceptionally, `commit-tree` wants an actual tree
+                # not a tree-ish
+                tree=f'{it.head}^{{tree}}',
+                parents=[it.head],
+                author=(project.github_name, project.github_email),
+                message=f'''\
 force rebuild
 
 uniquifier: {uniquifier}
 For-Commit-Id: {it.head}
 ''',
-            }).json()['sha']
+            ).stdout.strip()
+
             # see above, ideally we don't need to mark the real head as
             # `to_check` because it's an old commit but `DO UPDATE` is necessary
             # for `RETURNING` to work, and it doesn't really hurt (maybe)
@@ -187,34 +153,17 @@ For-Commit-Id: {it.head}
         'heads': heads,
         'commits': commits,
     })
-    # create staging branch from tmp
-    token = branch.project_id.github_token
-    for repo in branch.project_id.repo_ids.having_branch(branch):
-        it = staging_state[repo]
+    for repo, it in staging_state.items():
         _logger.info(
             "%s: create staging for %s:%s at %s",
             branch.project_id.name, repo.name, branch.name,
             it.head
         )
-        refname = 'staging.{}'.format(branch.name)
-        it.gh.set_ref(refname, it.head)
-
-        i = count()
-        @utils.backoff(delays=WAIT_FOR_VISIBILITY, exc=TimeoutError)
-        def wait_for_visibility():
-            if check_visibility(repo, refname, it.head, token):
-                _logger.info(
-                    "[repo] updated %s:%s to %s: ok (at %d/%d)",
-                    repo.name, refname, it.head,
-                    next(i), len(WAIT_FOR_VISIBILITY)
-                )
-                return
-            _logger.warning(
-                "[repo] updated %s:%s to %s: failed (at %d/%d)",
-                repo.name, refname, it.head,
-                next(i), len(WAIT_FOR_VISIBILITY)
-            )
-            raise TimeoutError("Staged head not updated after %d seconds" % sum(WAIT_FOR_VISIBILITY))
+        it.repo.stdout(False).check(True).push(
+            '-f',
+            git.source_url(repo, 'github'),
+            f'{it.head}:refs/heads/staging.{branch.name}',
+        )
 
     _logger.info("Created staging %s (%s) to %s", st, ', '.join(
         '%s[%s]' % (batch, batch.prs)
@@ -223,10 +172,36 @@ For-Commit-Id: {it.head}
     return st
 
 
+def ready_prs(for_branch: Branch) -> List[Tuple[int, PullRequests]]:
+    env = for_branch.env
+    env.cr.execute("""
+    SELECT
+      min(pr.priority) as priority,
+      array_agg(pr.id) AS match
+    FROM runbot_merge_pull_requests pr
+    WHERE pr.target = any(%s)
+      -- exclude terminal states (so there's no issue when
+      -- deleting branches & reusing labels)
+      AND pr.state != 'merged'
+      AND pr.state != 'closed'
+    GROUP BY
+        pr.target,
+        CASE
+            WHEN pr.label SIMILAR TO '%%:patch-[[:digit:]]+'
+                THEN pr.id::text
+            ELSE pr.label
+        END
+    HAVING
+        bool_or(pr.state = 'ready') or bool_or(pr.priority = 0)
+    ORDER BY min(pr.priority), min(pr.id)
+    """, [for_branch.ids])
+    browse = env['runbot_merge.pull_requests'].browse
+    return [(p, browse(ids)) for p, ids in env.cr.fetchall()]
+
+
 def staging_setup(
         target: Branch,
         batched_prs: List[PullRequests],
-        cleanup: contextlib.ExitStack
 ) -> Tuple[Dict[Repository, str], StagingState]:
     """Sets up the staging:
 
@@ -235,14 +210,11 @@ def staging_setup(
     - generates working copy for each repository with the target branch
     """
     all_prs: PullRequests = target.env['runbot_merge.pull_requests'].concat(*batched_prs)
-    cache_dir = user_cache_dir('mergebot')
     staging_state = {}
     original_heads = {}
     for repo in target.project_id.repo_ids.having_branch(target):
         gh = repo.github()
         head = gh.head(target.name)
-        # create tmp staging branch
-        gh.set_ref('tmp.{}'.format(target.name), head)
 
         source = git.get_local(repo, 'github')
         source.fetch(
@@ -255,14 +227,8 @@ def staging_setup(
             f'+refs/heads/{target.name}:refs/heads/{target.name}',
             *(pr.head for pr in all_prs if pr.repository == repo)
         )
-        Path(cache_dir, repo.name).parent.mkdir(parents=True, exist_ok=True)
-        d = cleanup.enter_context(tempfile.TemporaryDirectory(
-            prefix=f'{repo.name}-{target.name}-staging',
-            dir=cache_dir,
-        ))
-        working_copy = source.clone(d, branch=target.name)
         original_heads[repo] = head
-        staging_state[repo] = StagingSlice(gh=gh, head=head, working_copy=working_copy)
+        staging_state[repo] = StagingSlice(gh=gh, head=head, repo=source.stdout().with_config(text=True, check=False))
 
     return original_heads, staging_state
 
@@ -343,39 +309,29 @@ UNCHECKABLE = ['merge_method', 'overrides', 'draft']
 
 
 def stage_batch(env: api.Environment, prs: PullRequests, staging: StagingState) -> Batch:
-    """
-    Updates meta[*][head] on success
+    """Stages the batch represented by the ``prs`` recordset, onto the
+    current corresponding staging heads.
+
+    Alongside returning the newly created batch, updates ``staging[*].head``
+    in-place on success. On failure, the heads should not be touched.
     """
     new_heads: Dict[PullRequests, str] = {}
     pr_fields = env['runbot_merge.pull_requests']._fields
     for pr in prs:
-        gh = staging[pr.repository].gh
-
+        info = staging[pr.repository]
         _logger.info(
             "Staging pr %s for target %s; method=%s",
             pr.display_name, pr.target.name,
             pr.merge_method or (pr.squash and 'single') or None
         )
 
-        target = 'tmp.{}'.format(pr.target.name)
-        original_head = gh.head(target)
         try:
-            try:
-                method, new_heads[pr] = stage(pr, gh, target, related_prs=(prs - pr))
-                _logger.info(
-                    "Staged pr %s to %s by %s: %s -> %s",
-                    pr.display_name, pr.target.name, method,
-                    original_head, new_heads[pr]
-                )
-            except Exception:
-                # reset the head which failed, as rebase() may have partially
-                # updated it (despite later steps failing)
-                gh.set_ref(target, original_head)
-                # then reset every previous update
-                for to_revert in new_heads.keys():
-                    it = staging[to_revert.repository]
-                    it.gh.set_ref('tmp.{}'.format(to_revert.target.name), it.head)
-                raise
+            method, new_heads[pr] = stage(pr, info, related_prs=(prs - pr))
+            _logger.info(
+                "Staged pr %s to %s by %s: %s -> %s",
+                pr.display_name, pr.target.name, method,
+                info.head, new_heads[pr]
+            )
         except github.MergeError as e:
             raise exceptions.MergeError(pr) from e
         except exceptions.Mismatch as e:
@@ -419,9 +375,9 @@ def format_for_difflib(items: Iterator[Tuple[str, object]]) -> Iterator[str]:
 
 
 Method = Literal['merge', 'rebase-merge', 'rebase-ff', 'squash']
-def stage(pr: PullRequests, gh: github.GH, target: str, related_prs: PullRequests) -> Tuple[Method, str]:
+def stage(pr: PullRequests, info: StagingSlice, related_prs: PullRequests) -> Tuple[Method, str]:
     # nb: pr_commits is oldest to newest so pr.head is pr_commits[-1]
-    _, prdict = gh.pr(pr.number)
+    _, prdict = info.gh.pr(pr.number)
     commits = prdict['commits']
     method: Method = pr.merge_method or ('rebase-ff' if commits == 1 else None)
     if commits > 50 and method.startswith('rebase'):
@@ -431,7 +387,7 @@ def stage(pr: PullRequests, gh: github.GH, target: str, related_prs: PullRequest
             pr, "Merging PRs of 250 or more commits is not supported "
                 "(https://developer.github.com/v3/pulls/#list-commits-on-a-pull-request)"
         )
-    pr_commits = gh.commits(pr.number)
+    pr_commits = info.gh.commits(pr.number)
     for c in pr_commits:
         if not (c['commit']['author']['email'] and c['commit']['committer']['email']):
             raise exceptions.Unmergeable(
@@ -475,7 +431,7 @@ def stage(pr: PullRequests, gh: github.GH, target: str, related_prs: PullRequest
 
     if pr.reviewed_by and pr.reviewed_by.name == pr.reviewed_by.github_login:
         # XXX: find other trigger(s) to sync github name?
-        gh_name = gh.user(pr.reviewed_by.github_login)['name']
+        gh_name = info.gh.user(pr.reviewed_by.github_login)['name']
         if gh_name:
             pr.reviewed_by.name = gh_name
 
@@ -488,43 +444,46 @@ def stage(pr: PullRequests, gh: github.GH, target: str, related_prs: PullRequest
             fn = stage_rebase_ff
         case 'squash':
             fn = stage_squash
-    return method, fn(pr, gh, target, pr_commits, related_prs=related_prs)
+    return method, fn(pr, info, pr_commits, related_prs=related_prs)
 
-def stage_squash(pr: PullRequests, gh: github.GH, target: str, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
+def stage_squash(pr: PullRequests, info: StagingSlice, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
     msg = pr._build_merge_message(pr, related_prs=related_prs)
-    authorship = {}
 
     authors = {
         (c['commit']['author']['name'], c['commit']['author']['email'])
         for c in commits
     }
     if len(authors) == 1:
-        name, email = authors.pop()
-        authorship['author']  = {'name': name, 'email': email}
+        author = authors.pop()
     else:
         msg.headers.extend(sorted(
             ('Co-Authored-By', "%s <%s>" % author)
             for author in authors
         ))
+        author = (pr.repository.project_id.github_name, pr.repository.project_id.github_email)
 
     committers = {
         (c['commit']['committer']['name'], c['commit']['committer']['email'])
         for c in commits
     }
-    if len(committers) == 1:
-        name, email = committers.pop()
-        authorship['committer'] = {'name': name, 'email': email}
     # should committers also be added to co-authors?
+    committer = committers.pop() if len(committers) == 1 else None
 
-    original_head = gh.head(target)
-    merge_tree = gh.merge(pr.head, target, 'temp merge')['tree']['sha']
-    head = gh('post', 'git/commits', json={
-        **authorship,
-        'message': str(msg),
-        'tree': merge_tree,
-        'parents': [original_head],
-    }).json()['sha']
-    gh.set_ref(target, head)
+    r = info.repo.merge_tree(info.head, pr.head)
+    if r.returncode:
+        raise exceptions.MergeError(pr, r.stderr)
+    merge_tree = r.stdout.strip()
+
+    r = info.repo.commit_tree(
+        tree=merge_tree,
+        parents=[info.head],
+        message=str(msg),
+        author=author,
+        committer=committer or author,
+    )
+    if r.returncode:
+        raise exceptions.MergeError(pr, r.stderr)
+    head = r.stdout.strip()
 
     commits_map = {c['sha']: head for c in commits}
     commits_map[''] = head
@@ -532,25 +491,30 @@ def stage_squash(pr: PullRequests, gh: github.GH, target: str, commits: List[git
 
     return head
 
-def stage_rebase_ff(pr: PullRequests, gh: github.GH, target: str, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
+def stage_rebase_ff(pr: PullRequests, info: StagingSlice, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
     # updates head commit with PR number (if necessary) then rebases
     # on top of target
     msg = pr._build_merge_message(commits[-1]['commit']['message'], related_prs=related_prs)
     commits[-1]['commit']['message'] = str(msg)
     add_self_references(pr, commits[:-1])
-    head, mapping = gh.rebase(pr.number, target, commits=commits)
+    head, mapping = info.repo.rebase(info.head, commits=commits)
     pr.commits_map = json.dumps({**mapping, '': head})
     return head
 
-def stage_rebase_merge(pr: PullRequests, gh: github.GH, target: str, commits: List[github.PrCommit], related_prs: PullRequests) -> str :
+def stage_rebase_merge(pr: PullRequests, info: StagingSlice, commits: List[github.PrCommit], related_prs: PullRequests) -> str :
     add_self_references(pr, commits)
-    h, mapping = gh.rebase(pr.number, target, reset=True, commits=commits)
+    h, mapping = info.repo.rebase(info.head, commits=commits)
     msg = pr._build_merge_message(pr, related_prs=related_prs)
-    merge_head = gh.merge(h, target, str(msg))['sha']
+
+    project = pr.repository.project_id
+    merge_head= info.repo.merge(
+        info.head, h, str(msg),
+        author=(project.github_name, project.github_email),
+    )
     pr.commits_map = json.dumps({**mapping, '': merge_head})
     return merge_head
 
-def stage_merge(pr: PullRequests, gh: github.GH, target: str, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
+def stage_merge(pr: PullRequests, info: StagingSlice, commits: List[github.PrCommit], related_prs: PullRequests) -> str:
     pr_head = commits[-1] # oldest to newest
     base_commit = None
     head_parents = {p['sha'] for p in pr_head['parents']}
@@ -573,26 +537,37 @@ def stage_merge(pr: PullRequests, gh: github.GH, target: str, commits: List[gith
     if base_commit:
         # replicate pr_head with base_commit replaced by
         # the current head
-        original_head = gh.head(target)
-        merge_tree = gh.merge(pr_head['sha'], target, 'temp merge')['tree']['sha']
-        new_parents = [original_head] + list(head_parents - {base_commit})
+        t = info.repo.merge_tree(info.head, pr_head['sha'])
+        if t.returncode:
+            raise exceptions.MergeError(pr, t.stderr)
+        merge_tree = t.stdout.strip()
+        new_parents = [info.head] + list(head_parents - {base_commit})
         msg = pr._build_merge_message(pr_head['commit']['message'], related_prs=related_prs)
-        copy = gh('post', 'git/commits', json={
-            'message': str(msg),
-            'tree': merge_tree,
-            'author': pr_head['commit']['author'],
-            'committer': pr_head['commit']['committer'],
-            'parents': new_parents,
-        }).json()
-        gh.set_ref(target, copy['sha'])
+
+        d2t = itemgetter('name', 'email', 'date')
+        c = info.repo.commit_tree(
+            tree=merge_tree,
+            parents=new_parents,
+            message=str(msg),
+            author=d2t(pr_head['commit']['author']),
+            committer=d2t(pr_head['commit']['committer']),
+        )
+        if c.returncode:
+            raise exceptions.MergeError(pr, c.stderr)
+        copy = c.stdout.strip()
+
         # merge commit *and old PR head* map to the pr head replica
-        commits_map[''] = commits_map[pr_head['sha']] = copy['sha']
+        commits_map[''] = commits_map[pr_head['sha']] = copy
         pr.commits_map = json.dumps(commits_map)
-        return copy['sha']
+        return copy
     else:
         # otherwise do a regular merge
         msg = pr._build_merge_message(pr)
-        merge_head = gh.merge(pr.head, target, str(msg))['sha']
+        project = pr.repository.project_id
+        merge_head = info.repo.merge(
+            info.head, pr.head, str(msg),
+            author=(project.github_name, project.github_email),
+        )
         # and the merge commit is the normal merge head
         commits_map[''] = merge_head
         pr.commits_map = json.dumps(commits_map)
@@ -707,10 +682,10 @@ class Message:
 
     def __str__(self):
         if not self.headers:
-            return self.body + '\n'
+            return self.body.rstrip() + '\n'
 
-        with io.StringIO(self.body) as msg:
-            msg.write(self.body)
+        with io.StringIO() as msg:
+            msg.write(self.body.rstrip())
             msg.write('\n\n')
             # https://git.wiki.kernel.org/index.php/CommitMessageConventions
             # seems to mostly use capitalised names (rather than title-cased)

runbot_merge/tests/test_basic.py

@@ -1,7 +1,6 @@
 import datetime
 import itertools
 import json
-import textwrap
 import time
 from unittest import mock
 
@@ -124,7 +123,7 @@ def test_trivial_flow(env, repo, page, users, config):
         'b': 'a second file',
     }
     assert master.message == "gibberish\n\nblahblah\n\ncloses {repo.name}#1"\
-                             "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                             "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                              .format(repo=repo, reviewer=get_partner(env, users['reviewer']))
 
 class TestCommitMessage:
@@ -149,7 +148,7 @@ class TestCommitMessage:
 
         master = repo.commit('heads/master')
         assert master.message == "simple commit message\n\ncloses {repo.name}#1"\
-                                 "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                                 "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                                  .format(repo=repo, reviewer=get_partner(env, users['reviewer']))
 
     def test_commit_existing(self, env, repo, users, config):
@@ -174,7 +173,7 @@ class TestCommitMessage:
         master = repo.commit('heads/master')
         # closes #1 is already present, should not modify message
         assert master.message == "simple commit message that closes #1"\
-                                 "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                                 "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                                  .format(reviewer=get_partner(env, users['reviewer']))
 
     def test_commit_other(self, env, repo, users, config):
@@ -199,7 +198,7 @@ class TestCommitMessage:
         master = repo.commit('heads/master')
         # closes on another repositoy, should modify the commit message
         assert master.message == "simple commit message that closes odoo/enterprise#1\n\ncloses {repo.name}#1"\
-                                 "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                                 "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                                  .format(repo=repo, reviewer=get_partner(env, users['reviewer']))
 
     def test_commit_wrong_number(self, env, repo, users, config):
@@ -224,7 +223,7 @@ class TestCommitMessage:
         master = repo.commit('heads/master')
         # closes on another repositoy, should modify the commit message
         assert master.message == "simple commit message that closes #11\n\ncloses {repo.name}#1"\
-                                 "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                                 "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                                  .format(repo=repo, reviewer=get_partner(env, users['reviewer']))
 
     def test_commit_delegate(self, env, repo, users, config):
@@ -254,7 +253,7 @@ class TestCommitMessage:
 
         master = repo.commit('heads/master')
         assert master.message == "simple commit message\n\ncloses {repo.name}#1"\
-                                 "\n\nSigned-off-by: {reviewer.formatted_email}"\
+                                 "\n\nSigned-off-by: {reviewer.formatted_email}\n"\
                                  .format(repo=repo, reviewer=get_partner(env, users['other']))
 
     def test_commit_coauthored(self, env, repo, users, config):
@@ -292,7 +291,8 @@ Fixes a thing
 closes {repo.name}#1
 
 Signed-off-by: {reviewer.formatted_email}
-Co-authored-by: Bob <bob@example.com>""".format(
+Co-authored-by: Bob <bob@example.com>
+""".format(
             repo=repo,
             reviewer=get_partner(env, users['reviewer'])
         )
@@ -701,9 +701,9 @@ def test_ff_failure_batch(env, repo, users, config):
     reviewer = get_partner(env, users["reviewer"]).formatted_email
     assert messages == {
         'initial', 'NO!',
-        part_of('a1', pr_a), part_of('a2', pr_a), f'A\n\ncloses {pr_a.display_name}\n\nSigned-off-by: {reviewer}',
-        part_of('b1', pr_b), part_of('b2', pr_b), f'B\n\ncloses {pr_b.display_name}\n\nSigned-off-by: {reviewer}',
-        part_of('c1', pr_c), part_of('c2', pr_c), f'C\n\ncloses {pr_c.display_name}\n\nSigned-off-by: {reviewer}',
+        part_of('a1', pr_a), part_of('a2', pr_a), f'A\n\ncloses {pr_a.display_name}\n\nSigned-off-by: {reviewer}\n',
+        part_of('b1', pr_b), part_of('b2', pr_b), f'B\n\ncloses {pr_b.display_name}\n\nSigned-off-by: {reviewer}\n',
+        part_of('c1', pr_c), part_of('c2', pr_c), f'C\n\ncloses {pr_c.display_name}\n\nSigned-off-by: {reviewer}\n',
     }
 
 class TestPREdition:
@@ -1532,7 +1532,7 @@ commits, I need to know how to merge it:
         nb1 = node(part_of('B1', pr_id), node(part_of('B0', pr_id), nm2))
         reviewer = get_partner(env, users["reviewer"]).formatted_email
         merge_head = (
-            f'title\n\nbody\n\ncloses {pr_id.display_name}\n\nSigned-off-by: {reviewer}',
+            f'title\n\nbody\n\ncloses {pr_id.display_name}\n\nSigned-off-by: {reviewer}\n',
             frozenset([nm2, nb1])
         )
         assert staging == merge_head
@@ -1628,7 +1628,7 @@ commits, I need to know how to merge it:
         # then compare to the dag version of the right graph
         nm2 = node('M2', node('M1', node('M0')))
         reviewer = get_partner(env, users["reviewer"]).formatted_email
-        nb1 = node(f'B1\n\ncloses {pr_id.display_name}\n\nSigned-off-by: {reviewer}',
+        nb1 = node(f'B1\n\ncloses {pr_id.display_name}\n\nSigned-off-by: {reviewer}\n',
                    node(part_of('B0', pr_id), nm2))
         assert staging == nb1
 
@@ -1718,7 +1718,7 @@ commits, I need to know how to merge it:
         c0 = node('C0', m)
         reviewer = get_partner(env, users["reviewer"]).formatted_email
         expected = node('gibberish\n\nblahblah\n\ncloses {}#{}'
-                        '\n\nSigned-off-by: {}'.format(repo.name, prx.number, reviewer), m, c0)
+                        '\n\nSigned-off-by: {}\n'.format(repo.name, prx.number, reviewer), m, c0)
         assert log_to_node(repo.log('heads/master')), expected
         pr = env['runbot_merge.pull_requests'].search([
             ('repository.name', '=', repo.name),
@@ -1760,7 +1760,7 @@ commits, I need to know how to merge it:
         c0 = node('C0', m)
         reviewer = get_partner(env, users["reviewer"]).formatted_email
         expected = node('gibberish\n\ncloses {}#{}'
-                        '\n\nSigned-off-by: {}'.format(repo.name, prx.number, reviewer), m, c0)
+                        '\n\nSigned-off-by: {}\n'.format(repo.name, prx.number, reviewer), m, c0)
         assert log_to_node(repo.log('heads/master')), expected
 
     @pytest.mark.parametrize('separator', [
@@ -1790,15 +1790,15 @@ commits, I need to know how to merge it:
         env.run_crons()
 
         head = repo.commit('heads/master')
-        assert head.message == textwrap.dedent(f"""\
-        title
+        assert head.message == f"""\
+title
 
-        first
+first
 
-        closes {repo.name}#{pr.number}
+closes {repo.name}#{pr.number}
 
-        Signed-off-by: {reviewer}
-        """).strip(), "should not contain the content which follows the thematic break"
+Signed-off-by: {reviewer}
+""", "should not contain the content which follows the thematic break"
 
     def test_pr_message_setex_title(self, repo, env, users, config):
         """ should not break on a proper SETEX-style title """
@@ -1830,21 +1830,21 @@ removed
         env.run_crons()
 
         head = repo.commit('heads/master')
-        assert head.message == textwrap.dedent(f"""\
-        title
+        assert head.message == f"""\
+title
 
-        Title
-        ---
-        This is some text
+Title
+---
+This is some text
 
-        Title 2
-        -------
-        This is more text
+Title 2
+-------
+This is more text
 
-        closes {repo.name}#{pr.number}
+closes {repo.name}#{pr.number}
 
-        Signed-off-by: {reviewer}
-        """).strip(), "should not break the SETEX titles"
+Signed-off-by: {reviewer}
+""", "should not break the SETEX titles"
 
     def test_rebase_no_edit(self, repo, env, users, config):
         """ Only the merge messages should be de-breaked
@@ -1867,17 +1867,17 @@ removed
         env.run_crons()
 
         head = repo.commit('heads/master')
-        assert head.message == textwrap.dedent(f"""\
-        Commit
+        assert head.message == f"""\
+Commit
 
-        first
-        ***
-        second
+first
+***
+second
 
-        closes {repo.name}#{pr.number}
+closes {repo.name}#{pr.number}
 
-        Signed-off-by: {reviewer}
-        """).strip(), "squashed / rebased messages should not be stripped"
+Signed-off-by: {reviewer}
+""", "squashed / rebased messages should not be stripped"
 
     def test_title_no_edit(self, repo, env, users, config):
         """The first line of a commit message should not be taken in account for
@@ -1909,13 +1909,15 @@ thing: thong
 
 closes {pr_id.display_name}
 
-Signed-off-by: {reviewer}"""
+Signed-off-by: {reviewer}
+"""
         assert repo.commit(staging_head.parents[0]).message == f"""\
 Some: thing
 
 is odd
 
-Part-of: {pr_id.display_name}"""
+Part-of: {pr_id.display_name}
+"""
 
     def test_pr_mergehead(self, repo, env, config):
         """ if the head of the PR is a merge commit and one of the parents is
@@ -2000,7 +2002,7 @@ Part-of: {pr_id.display_name}"""
         m1 = node('M1')
         reviewer = get_partner(env, users["reviewer"]).formatted_email
         expected = node(
-            'T\n\nTT\n\ncloses {}#{}\n\nSigned-off-by: {}'.format(repo.name, prx.number, reviewer),
+            'T\n\nTT\n\ncloses {}#{}\n\nSigned-off-by: {}\n'.format(repo.name, prx.number, reviewer),
             node('M2', m1),
             node('C1', node('C0', m1), node('B0', m1))
         )
@@ -2076,7 +2078,7 @@ Part-of: {pr_id.display_name}"""
 
 closes {pr1_id.display_name}
 
-Signed-off-by: {get_partner(env, users["reviewer"]).formatted_email}\
+Signed-off-by: {get_partner(env, users["reviewer"]).formatted_email}
 """
         assert one['commit']['committer']['name'] == a_user['name']
         assert one['commit']['committer']['email'] == a_user['email']
@@ -2107,7 +2109,7 @@ closes {pr2_id.display_name}
 
 Signed-off-by: {get_partner(env, users["reviewer"]).formatted_email}
 Co-authored-by: {a_user['name']} <{a_user['email']}>
-Co-authored-by: {other_user['name']} <{other_user['email']}>\
+Co-authored-by: {other_user['name']} <{other_user['email']}>
 """
         assert repo.read_tree(repo.commit(two['sha'])) == {
             'a': '0',
@@ -2667,12 +2669,12 @@ class TestBatching(object):
         staging = log_to_node(log)
         reviewer = get_partner(env, users["reviewer"]).formatted_email
         p1 = node(
-            'title PR1\n\nbody PR1\n\ncloses {}\n\nSigned-off-by: {}'.format(pr1.display_name, reviewer),
+            'title PR1\n\nbody PR1\n\ncloses {}\n\nSigned-off-by: {}\n'.format(pr1.display_name, reviewer),
             node('initial'),
             node(part_of('commit_PR1_01', pr1), node(part_of('commit_PR1_00', pr1), node('initial')))
         )
         p2 = node(
-            'title PR2\n\nbody PR2\n\ncloses {}\n\nSigned-off-by: {}'.format(pr2.display_name, reviewer),
+            'title PR2\n\nbody PR2\n\ncloses {}\n\nSigned-off-by: {}\n'.format(pr2.display_name, reviewer),
             p1,
             node(part_of('commit_PR2_01', pr2), node(part_of('commit_PR2_00', pr2), p1))
         )
@@ -2707,12 +2709,12 @@ class TestBatching(object):
         reviewer = get_partner(env, users["reviewer"]).formatted_email
 
         p1 = node(
-            'title PR1\n\nbody PR1\n\ncloses {}#{}\n\nSigned-off-by: {}'.format(repo.name, pr1.number, reviewer),
+            'title PR1\n\nbody PR1\n\ncloses {}#{}\n\nSigned-off-by: {}\n'.format(repo.name, pr1.number, reviewer),
             node('initial'),
             node('commit_PR1_01', node('commit_PR1_00', node('initial')))
         )
         p2 = node(
-            'title PR2\n\nbody PR2\n\ncloses {}#{}\n\nSigned-off-by: {}'.format(repo.name, pr2.number, reviewer),
+            'title PR2\n\nbody PR2\n\ncloses {}#{}\n\nSigned-off-by: {}\n'.format(repo.name, pr2.number, reviewer),
             p1,
             node('commit_PR2_01', node('commit_PR2_00', node('initial')))
         )
@@ -2741,8 +2743,8 @@ class TestBatching(object):
 
         staging = log_to_node(log)
         reviewer = get_partner(env, users["reviewer"]).formatted_email
-        expected = node('commit_PR2_00\n\ncloses {}#{}\n\nSigned-off-by: {}'.format(repo.name, pr2.number, reviewer),
-             node('commit_PR1_00\n\ncloses {}#{}\n\nSigned-off-by: {}'.format(repo.name, pr1.number, reviewer),
+        expected = node('commit_PR2_00\n\ncloses {}#{}\n\nSigned-off-by: {}\n'.format(repo.name, pr2.number, reviewer),
+             node('commit_PR1_00\n\ncloses {}#{}\n\nSigned-off-by: {}\n'.format(repo.name, pr1.number, reviewer),
                   node('initial')))
         assert staging == expected
 

runbot_merge/tests/test_multirepo.py

@@ -435,7 +435,7 @@ def test_merge_fail(env, project, repo_a, repo_b, users, config):
         )
     env.run_crons()
 
-    s2 = to_pr(env, pr2a) | to_pr(env, pr2b)
+    pr2a_id, pr2b_id = s2 = to_pr(env, pr2a) | to_pr(env, pr2b)
     st = env['runbot_merge.stagings'].search([])
     assert set(st.batch_ids.prs.ids) == set(s2.ids)
 
@@ -453,12 +453,14 @@ def test_merge_fail(env, project, repo_a, repo_b, users, config):
         c['commit']['message']
         for c in repo_a.log('heads/staging.master')
     ] == [
-        """commit_do-b-thing_00
+        f"""\
+commit_do-b-thing_00
 
-closes %s
+closes {pr2a_id.display_name}
 
-Related: %s
-Signed-off-by: %s""" % (s2[0].display_name, s2[1].display_name, reviewer),
+Related: {pr2b_id.display_name}
+Signed-off-by: {reviewer}
+""",
         'initial'
     ], "dummy commit + squash-merged PR commit + root commit"