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author | Sean McGivern <sean@gitlab.com> | 2017-11-15 20:22:18 +0300 |
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committer | Sean McGivern <sean@gitlab.com> | 2017-11-23 15:14:56 +0300 |
commit | 991bf24ec8890eca248a00deb4f33f309c9ffb83 (patch) | |
tree | dd294550817dcfdaecdf934a52119731cf0ff193 /app/services | |
parent | e548c613346a09ba2fc8dfd6ed64da6628ec6a45 (diff) |
Use latest_merge_request_diff association
Compared to the merge_request_diff association:
1. It's simpler to query. The query uses a foreign key to the
merge_request_diffs table, so no ordering is necessary.
2. It's faster for preloading. The merge_request_diff association has to load
every diff for the MRs in the set, then discard all but the most recent for
each. This association means that Rails can just query for N diffs from N
MRs.
3. It's more complicated to update. This is a bidirectional foreign key, so we
need to update two tables when adding a diff record. This also means we need
to handle this as a special case when importing a GitLab project.
There is some juggling with this association in the merge request model:
* `MergeRequest#latest_merge_request_diff` is _always_ the latest diff.
* `MergeRequest#merge_request_diff` reuses
`MergeRequest#latest_merge_request_diff` unless:
* Arguments are passed. These are typically to force-reload the association.
* It doesn't exist. That means we might be trying to implicitly create a
diff. This only seems to happen in specs.
* The association is already loaded. This is important for the reasons
explained in the comment, which I'll reiterate here: if we a) load a
non-latest diff, then b) get its `merge_request`, then c) get that MR's
`merge_request_diff`, we should get the diff we loaded in c), even though
that's not the latest diff.
Basically, `MergeRequest#merge_request_diff` is the latest diff in most cases,
but not quite all.
Diffstat (limited to 'app/services')
-rw-r--r-- | app/services/merge_requests/refresh_service.rb | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/app/services/merge_requests/refresh_service.rb b/app/services/merge_requests/refresh_service.rb index fc100580c4f..bf3d4855122 100644 --- a/app/services/merge_requests/refresh_service.rb +++ b/app/services/merge_requests/refresh_service.rb @@ -35,7 +35,7 @@ module MergeRequests # target branch manually def close_merge_requests commit_ids = @commits.map(&:id) - merge_requests = @project.merge_requests.preload(:merge_request_diff).opened.where(target_branch: @branch_name).to_a + merge_requests = @project.merge_requests.preload(:latest_merge_request_diff).opened.where(target_branch: @branch_name).to_a merge_requests = merge_requests.select(&:diff_head_commit) merge_requests = merge_requests.select do |merge_request| |