Add latest changes from gitlab-org/gitlab@master

1 files changed, 30 insertions, 0 deletions

diff --git a/doc/user/project/repository/index.md b/doc/user/project/repository/index.md
index 7d83800659b..bcdb626d0f2 100644
--- a/doc/user/project/repository/index.md
+++ b/doc/user/project/repository/index.md
@@ -306,3 +306,33 @@ The same approach should also allow misidentified file types to be fixed.
    ```
 
   `*.txt` files have an entry in the heuristics file. This example prevents parsing of these files.
+
+### Search sequence of pushes to a repository
+
+If it seems that a commit has gone "missing", search the sequence of pushes to a repository.
+[This StackOverflow article](https://stackoverflow.com/questions/13468027/the-mystery-of-the-missing-commit-across-merges)
+describes how you can end up in this state without a force push. Another cause can be a misconfigured [server hook](../../../administration/server_hooks.md) that changes a HEAD ref in a `git reset` operation.
+
+If you look at the output from the sample code below for the target branch, you
+see a discontinuity in the from/to commits as you step through the output.
+The `commit_from` of each new push should equal the `commit_to` of the previous push.
+A break in that sequence indicates one or more commits have been "lost" from the repository history.
+
+Using the [rails console](../../../administration/operations/rails_console.md#starting-a-rails-console-session), the following example checks the last 100 pushes and prints the `commit_from` and `commit_to` entries:
+
+```ruby
+p = Project.find_by_full_path('project/path')
+p.events.pushed_action.last(100).each do |e|
+  puts "%-20.20s %8s...%8s (%s)", e.push_event_payload[:ref], e.push_event_payload[:commit_from], e.push_event_payload[:commit_to], e.author.try(:username)
+end ; nil
+```
+
+Example output showing break in sequence at line 4:
+
+```plaintext
+master f21b07713251e04575908149bdc8ac1f105aabc3...6bc56c1f46244792222f6c85b11606933af171de root
+master 6bc56c1f46244792222f6c85b11606933af171de...132da6064f5d3453d445fd7cb452b148705bdc1b root
+master 132da6064f5d3453d445fd7cb452b148705bdc1b...a62e1e693150a2e46ace0ce696cd4a52856dfa65 root
+master 58b07b719a4b0039fec810efa52f479ba1b84756...f05321a5b5728bd8a89b7bf530aa44043c951dce root
+master f05321a5b5728bd8a89b7bf530aa44043c951dce...7d02e575fd790e76a3284ee435368279a5eb3773 root
+```