Inline comments for first commit

When I try send inline comment for first commit file I get 500 response.
Logs:

NoMethodError (undefined method `line_code_for_position' for nil:NilClass):
lib/gitlab/diff/position.rb:136:in `line_code'
app/models/diff_note.rb:86:in `set_line_code'
app/services/notes/create_service.rb:14:in `execute'
app/controllers/projects/notes_controller.rb:25:in `create'
lib/gitlab/middleware/go.rb:16:in `call'

Please could you provide some more information about the environment where you have noticed the problem:

• Run a diagnostic check of GitLab and it's components:

sudo gitlab-rake gitlab:check

• Gather GitLab specific environment information:

sudo gitlab-rake gitlab:env:info

Please could you add some more information to your report. Please provide at least one of the following:

• Step-by-step instructions to reproduce the problem
• A sample project on GitLab.com exhibiting the behaviour

Added ~65372 label

First of all, I want to say that the same behavior can be reproduced on gitlab.com.
Step-by-step instruction:

1. For example I have a project on gitlab.com with only one commit.
2. I tried to write the inline comment
3. Comments not created
4. In the 'network' panel of chrome developer tools I saw that the query returns a 500 error

On my server:

1. gitlab:check - all ok
2. gitlab:env:info:

System information
System:		Ubuntu 14.04
Current User:	git
Using RVM:	no
Ruby Version:	2.1.8p440
Gem Version:	2.5.1
Bundler Version:1.10.6
Rake Version:	10.5.0
Sidekiq Version:4.1.4

GitLab information
Version:	8.10.5
Revision:	5f47c35
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		http://code.realext.com.ua
HTTP Clone URL:	http://code.realext.com.ua/some-group/some-project.git
SSH Clone URL:	git@code.realext.com.ua:some-group/some-project.git
Using LDAP:	no
Using Omniauth:	no

GitLab Shell
Version:	3.2.1
Repository storage paths:
- default: 	/var/opt/gitlab/git-data/repositories
Hooks:		/opt/gitlab/embedded/service/gitlab-shell/hooks/
Git:		/opt/gitlab/embedded/bin/git

I am experiencing the same problem after upgrading to 8.10.5.

Results are the same as Andrey's.

Removed ~65372 label

Added ~12980 code review labels

Added reproduced on GitLab.com label

@realext @adyromantika Thanks for your reports and extra info. I did manage to reproduce this on GitLab.com.

Attempting to add an inline comment to the following commit, for the first line, will result in a 500 error.

• https://gitlab.com/issue-reproduce/test-inline-comments/commit/550e46c80c69956b3b18f2c95a79aebde8d0cefd

@DouweM who should be assigned to look into this?

mentioned in issue #19582 (closed)

Added regression label

Reassigned to @smcgivern

Milestone changed to %8.11

Started branch 20895-inline-comments-for-first-commit

mentioned in merge request !5900 (merged)

Status changed to closed by merge request !5900 (merged)

mentioned in commit 95cf5a09

mentioned in merge request !14785