Merge branch 'fix-huge-mr' into 'master'

Fix huge merge requests

* Refactored suppress logic for diffs
* Increase grit memory limit (should mix most of 502 errors when create MR)
* show first 100 files for huge diffs

Fixes #1424

See merge request !970

23 files changed, 337 insertions, 302 deletions

diff --git a/app/assets/stylesheets/sections/commits.scss b/app/assets/stylesheets/sections/commits.scss
index 9b148390115..684e8377a7b 100644
--- a/app/assets/stylesheets/sections/commits.scss
+++ b/app/assets/stylesheets/sections/commits.scss
@@ -112,7 +112,9 @@
 
 .commit-stat-summary {
   color: #666;
-  line-height: 2;
+  font-size: 14px;
+  font-weight: normal;
+  padding: 10px 0;
 }
 
 .commit-info-row {
diff --git a/app/controllers/projects/commit_controller.rb b/app/controllers/projects/commit_controller.rb
index 860ab408299..c344297ba8a 100644
--- a/app/controllers/projects/commit_controller.rb
+++ b/app/controllers/projects/commit_controller.rb
@@ -20,11 +20,10 @@ class Projects::CommitController < Projects::ApplicationController
                 end
 
     begin
-      @suppress_diff = true if commit.diff_suppress? && !params[:force_show_diff]
-      @force_suppress_diff = commit.diff_force_suppress?
+      @diffs = @commit.diffs
     rescue Grit::Git::GitTimeout
-      @suppress_diff = true
-      @status = :huge_commit
+      @diffs = []
+      @diff_timeout = true
     end
 
     @note = project.build_commit_note(commit)
@@ -38,12 +37,7 @@ class Projects::CommitController < Projects::ApplicationController
     }
 
     respond_to do |format|
-      format.html do
-        if @status == :huge_commit
-          render "huge_commit" and return
-        end
-      end
-
+      format.html
       format.diff  { render text: @commit.to_diff }
       format.patch { render text: @commit.to_patch }
     end
diff --git a/app/controllers/projects/compare_controller.rb b/app/controllers/projects/compare_controller.rb
index 234b6058ff0..eae96396574 100644
--- a/app/controllers/projects/compare_controller.rb
+++ b/app/controllers/projects/compare_controller.rb
@@ -15,11 +15,7 @@ class Projects::CompareController < Projects::ApplicationController
     @diffs         = compare.diffs
     @refs_are_same = compare.same
     @line_notes    = []
-    @timeout       = compare.timeout
-
-    diff_line_count = Commit::diff_line_count(@diffs)
-    @suppress_diff = Commit::diff_suppress?(@diffs, diff_line_count) && !params[:force_show_diff]
-    @force_suppress_diff = Commit::diff_force_suppress?(@diffs, diff_line_count)
+    @diff_timeout  = compare.timeout
   end
 
   def create
diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index bdd614973b7..fcc6384e27c 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -34,6 +34,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   def show
     @note_counts = Note.where(commit_id: @merge_request.commits.map(&:id)).
         group(:commit_id).count
+
     respond_to do |format|
       format.html
       format.diff { render text: @merge_request.to_diff(current_user) }
@@ -43,16 +44,13 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
   def diffs
     @commit = @merge_request.last_commit
-
     @comments_allowed = @reply_allowed = true
-    @comments_target = {noteable_type: 'MergeRequest',
-                        noteable_id: @merge_request.id}
+    @comments_target = {
+      noteable_type: 'MergeRequest',
+      noteable_id: @merge_request.id
+    }
     @line_notes = @merge_request.notes.where("line_code is not null")
 
-    diff_line_count = Commit::diff_line_count(@merge_request.diffs)
-    @suppress_diff = Commit::diff_suppress?(@merge_request.diffs, diff_line_count) && !params[:force_show_diff]
-    @force_suppress_diff = Commit::diff_force_suppress?(@merge_request.diffs, diff_line_count)
-
     respond_to do |format|
       format.html
       format.json { render json: { html: view_to_html_string("projects/merge_requests/show/_diffs") } }
@@ -60,54 +58,22 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   end
 
   def new
-    params[:merge_request] ||= ActionController::Parameters.new(
-      source_project: @project
-    )
-
-    @merge_request = MergeRequest.new(merge_request_params)
-    @merge_request.source_project = @project unless @merge_request.source_project
-    @merge_request.target_project ||= (@project.forked_from_project || @project)
-    @target_branches = @merge_request.target_project.nil? ? [] : @merge_request.target_project.repository.branch_names
-    @merge_request.target_branch ||= @merge_request.target_project.default_branch
-    @source_project = @merge_request.source_project
-
-    if @merge_request.target_branch && @merge_request.source_branch
-      compare_action = Gitlab::Satellite::CompareAction.new(
-        current_user,
-        @merge_request.target_project,
-        @merge_request.target_branch,
-        @merge_request.source_project,
-        @merge_request.source_branch
-      )
-
-      @compare_failed = false
-      @commits = compare_action.commits
-
-      if @commits
-        @commits.map! { |commit| Commit.new(commit) }
-        @commit = @commits.first
-      else
-        # false value because failed to get commits from satellite
-        @commits = []
-        @compare_failed = true
-      end
-
-      @note_counts = Note.where(commit_id: @commits.map(&:id)).
-          group(:commit_id).count
-
-      begin
-        @diffs = compare_action.diffs
-        @merge_request.title = @merge_request.source_branch.titleize.humanize
-        @target_project = @merge_request.target_project
-        @target_repo = @target_project.repository
-
-        diff_line_count = Commit::diff_line_count(@diffs)
-        @suppress_diff = Commit::diff_suppress?(@diffs, diff_line_count)
-        @force_suppress_diff = @suppress_diff
-      rescue Gitlab::Satellite::BranchesWithoutParent
-        @error = "Selected branches have no common commit so they cannot be merged."
-      end
-    end
+    params[:merge_request] ||= ActionController::Parameters.new(source_project: @project)
+    @merge_request = MergeRequests::BuildService.new(project, current_user, merge_request_params).execute
+
+    @target_branches = if @merge_request.target_project
+                         @merge_request.target_project.repository.branch_names
+                       else
+                         []
+                       end
+
+    @target_project = merge_request.target_project
+    @source_project = merge_request.source_project
+    @commits = @merge_request.compare_commits
+    @commit = @merge_request.compare_base_commit
+    @diffs = @merge_request.compare_diffs
+    @note_counts = Note.where(commit_id: @commits.map(&:id)).
+      group(:commit_id).count
   end
 
   def edit
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
new file mode 100644
index 00000000000..ee4d4fbdff5
--- /dev/null
+++ b/app/helpers/diff_helper.rb
@@ -0,0 +1,22 @@
+module DiffHelper
+  def safe_diff_files(diffs)
+    if diff_hard_limit_enabled?
+      diffs.first(Commit::DIFF_HARD_LIMIT_FILES)
+    else
+      diffs.first(Commit::DIFF_SAFE_FILES)
+    end
+  end
+
+  def show_diff_size_warninig?(diffs)
+    safe_diff_files(diffs).size < diffs.size
+  end
+
+  def diff_hard_limit_enabled?
+    # Enabling hard limit allows user to see more diff information
+    if params[:force_show_diff].present?
+      true
+    else
+      false
+    end
+  end
+end
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index ba4c7068e90..bc2ec84302d 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -221,4 +221,10 @@ module ProjectsHelper
       "Never"
     end
   end
+
+  def contribution_guide_url(project)
+    if project && project.repository.contribution_guide
+      project_blob_path(project, tree_join(project.default_branch, project.repository.contribution_guide.name))
+    end
+  end
 end
diff --git a/app/models/commit.rb b/app/models/commit.rb
index 82876e10446..ff5392957ce 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -12,6 +12,7 @@ class Commit
   # User can force display of diff above this size
   DIFF_SAFE_FILES  = 100
   DIFF_SAFE_LINES  = 5000
+
   # Commits above this size will not be rendered in HTML
   DIFF_HARD_LIMIT_FILES = 1000
   DIFF_HARD_LIMIT_LINES = 50000
@@ -23,23 +24,7 @@ class Commit
 
     # Calculate number of lines to render for diffs
     def diff_line_count(diffs)
-      diffs.reduce(0){|sum, d| sum + d.diff.lines.count}
-    end
-
-    def diff_suppress?(diffs, line_count = nil)
-      # optimize - check file count first
-      return true if diffs.size > DIFF_SAFE_FILES
-
-      line_count ||= Commit::diff_line_count(diffs)
-      line_count > DIFF_SAFE_LINES
-    end
-
-    def diff_force_suppress?(diffs, line_count = nil)
-      # optimize - check file count first
-      return true if diffs.size > DIFF_HARD_LIMIT_FILES
-
-      line_count ||= Commit::diff_line_count(diffs)
-      line_count > DIFF_HARD_LIMIT_LINES
+      diffs.reduce(0) { |sum, d| sum + d.diff.lines.count }
     end
   end
 
@@ -60,14 +45,6 @@ class Commit
     @diff_line_count
   end
 
-  def diff_suppress?
-    Commit::diff_suppress?(self.diffs, diff_line_count)
-  end
-
-  def diff_force_suppress?
-    Commit::diff_force_suppress?(self.diffs, diff_line_count)
-  end
-
   # Returns a string describing the commit for use in a link title
   #
   # Example
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 597e02d498b..28486fb41c6 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -42,6 +42,11 @@ class MergeRequest < ActiveRecord::Base
   # It allows us to close or modify broken merge requests
   attr_accessor :allow_broken
 
+  # Temporary fields to store compare vars
+  # when creating new merge request
+  attr_accessor :can_be_created, :compare_failed, :compare_base_commit,
+    :compare_commits, :compare_diffs
+
   ActsAsTaggableOn.strict_case_match = true
   acts_as_taggable_on :labels
 
diff --git a/app/services/merge_requests/build_service.rb b/app/services/merge_requests/build_service.rb
new file mode 100644
index 00000000000..fb487539687
--- /dev/null
+++ b/app/services/merge_requests/build_service.rb
@@ -0,0 +1,70 @@
+module MergeRequests
+  class BuildService < MergeRequests::BaseService
+    def execute
+      merge_request = MergeRequest.new(params)
+
+      # Set MR attributes
+      merge_request.can_be_created = false
+      merge_request.compare_failed = false
+      merge_request.compare_commits = []
+      merge_request.compare_diffs = []
+      merge_request.source_project = project unless merge_request.source_project
+      merge_request.target_project ||= (project.forked_from_project || project)
+      merge_request.target_branch ||= merge_request.target_project.default_branch
+
+      unless merge_request.target_branch && merge_request.source_branch
+        return build_failed(merge_request, "You must select source and target branches")
+      end
+
+      # Generate suggested MR title based on source branch name
+      merge_request.title = merge_request.source_branch.titleize.humanize
+
+      # Try to compare branches to get commits list and diffs
+      compare_action = Gitlab::Satellite::CompareAction.new(
+        current_user,
+        merge_request.target_project,
+        merge_request.target_branch,
+        merge_request.source_project,
+        merge_request.source_branch
+      )
+
+      commits = compare_action.commits
+
+      # At this point we decide if merge request can be created
+      # If we have at least one commit to merge -> creation allowed
+      if commits.present?
+        merge_request.compare_commits = Commit.decorate(commits)
+        merge_request.compare_base_commit = Commit.new(commits.first)
+        merge_request.can_be_created = true
+        merge_request.compare_failed = false
+
+        # Try to collect diff for merge request.
+        diffs = compare_action.diffs
+
+        if diffs.present?
+          merge_request.compare_diffs = diffs
+
+        elsif diffs == false
+          # satellite timeout return false
+          merge_request.can_be_created = false
+          merge_request.compare_failed = true
+        end
+      else
+        merge_request.can_be_created = false
+        merge_request.compare_failed = true
+      end
+
+      merge_request
+
+    rescue Gitlab::Satellite::BranchesWithoutParent
+      return build_failed(merge_request, "Selected branches have no common commit so they cannot be merged.")
+    end
+
+    def build_failed(merge_request, message)
+      merge_request.errors.add(:base, message)
+      merge_request.compare_commits = []
+      merge_request.can_be_created = false
+      merge_request
+    end
+  end
+end
diff --git a/app/views/projects/commit/huge_commit.html.haml b/app/views/projects/commit/huge_commit.html.haml
deleted file mode 100644
index 398ce771426..00000000000
--- a/app/views/projects/commit/huge_commit.html.haml
+++ /dev/null
@@ -1,3 +0,0 @@
-= render "projects/commit/commit_box"
-.alert.alert-danger
-  %h4 Commit diffs are too big to be displayed
diff --git a/app/views/projects/commit/show.html.haml b/app/views/projects/commit/show.html.haml
index da1b4c10f87..0a15aef6cb7 100644
--- a/app/views/projects/commit/show.html.haml
+++ b/app/views/projects/commit/show.html.haml
@@ -1,3 +1,3 @@
 = render "commit_box"
-= render "projects/commits/diffs", diffs: @commit.diffs, project: @project
+= render "projects/commits/diffs", diffs: @diffs, project: @project
 = render "projects/notes/notes_with_form"
diff --git a/app/views/projects/commits/_diff_file.html.haml b/app/views/projects/commits/_diff_file.html.haml
new file mode 100644
index 00000000000..45d1cd9c9a0
--- /dev/null
+++ b/app/views/projects/commits/_diff_file.html.haml
@@ -0,0 +1,48 @@
+- file = project.repository.blob_at(@commit.id, diff.new_path)
+- file = project.repository.blob_at(@commit.parent_id, diff.old_path) unless file
+- return unless file
+.diff-file{id: "diff-#{i}"}
+  .diff-header{id: "file-path-#{hexdigest(diff.new_path || diff.old_path)}"}
+    - if diff.deleted_file
+      %span= diff.old_path
+
+      .diff-btn-group
+        - if @commit.parent_ids.present?
+          = link_to project_blob_path(project, tree_join(@commit.parent_id, diff.new_path)), { class: 'btn btn-small view-file' } do
+            View file @
+            %span.commit-short-id= @commit.short_id(6)
+    - else
+      %span= diff.new_path
+      - if diff_file_mode_changed?(diff)
+        %span.file-mode= "#{diff.a_mode} → #{diff.b_mode}"
+
+      .diff-btn-group
+        = link_to "#", class: "js-toggle-diff-comments btn btn-small" do
+          %i.icon-chevron-down
+          Diff comments
+        &nbsp;
+
+        - if @merge_request && @merge_request.source_project
+          = link_to project_edit_tree_path(@merge_request.source_project, tree_join(@merge_request.source_branch, diff.new_path), from_merge_request_id: @merge_request.id), { class: 'btn btn-small' } do
+            Edit
+          &nbsp;
+
+        = link_to project_blob_path(project, tree_join(@commit.id, diff.new_path)), { class: 'btn btn-small view-file' } do
+          View file @
+          %span.commit-short-id= @commit.short_id(6)
+
+
+  .diff-content
+    -# Skipp all non non-supported blobs
+    - return unless file.respond_to?('text?')
+    - if file.text?
+      - if params[:view] == 'parallel'
+        = render "projects/commits/parallel_view", diff: diff, project: project, file: file, index: i
+      - else
+        = render "projects/commits/text_file", diff: diff, index: i
+    - elsif file.image?
+      - old_file = project.repository.blob_at(@commit.parent_id, diff.old_path) if @commit.parent_id
+      = render "projects/commits/image", diff: diff, old_file: old_file, file: file, index: i
+    - else
+      .nothing-here-block No preview for this file type
+
diff --git a/app/views/projects/commits/_diff_head.html.haml b/app/views/projects/commits/_diff_head.html.haml
deleted file mode 100644
index 5aa542287fe..00000000000
--- a/app/views/projects/commits/_diff_head.html.haml
+++ /dev/null
@@ -1,26 +0,0 @@
-%ul.bordered-list
-  - diffs.each_with_index do |diff, i|
-    %li
-      - if diff.deleted_file
-        %span.deleted-file
-          %a{href: "#diff-#{i}"}
-            %i.icon-minus
-            = diff.old_path
-      - elsif diff.renamed_file
-        %span.renamed-file
-          %a{href: "#diff-#{i}"}
-            %i.icon-minus
-            = diff.old_path
-            = "->"
-            = diff.new_path
-      - elsif diff.new_file
-        %span.new-file
-          %a{href: "#diff-#{i}"}
-            %i.icon-plus
-            = diff.new_path
-      - else
-        %span.edit-file
-          %a{href: "#diff-#{i}"}
-            %i.icon-adjust
-            = diff.new_path
-
diff --git a/app/views/projects/commits/_diff_stats.html.haml b/app/views/projects/commits/_diff_stats.html.haml
new file mode 100644
index 00000000000..846a1ee10e6
--- /dev/null
+++ b/app/views/projects/commits/_diff_stats.html.haml
@@ -0,0 +1,41 @@
+.js-toggle-container
+  .commit-stat-summary
+    Showing
+    %strong.cdark #{pluralize(diffs.count, "changed file")}
+    - if current_controller?(:commit)
+      - unless @commit.has_zero_stats?
+        with
+        %strong.cgreen #{@commit.stats.additions} additions
+        and
+        %strong.cred #{@commit.stats.deletions} deletions
+    &nbsp;
+    = link_to '#', class: 'btn btn-small js-toggle-button' do
+      Show diff stats
+      %i.icon-chevron-down
+  .file-stats.js-toggle-content.hide
+    %ul.bordered-list
+      - diffs.each_with_index do |diff, i|
+        %li
+          - if diff.deleted_file
+            %span.deleted-file
+              %a{href: "#diff-#{i}"}
+                %i.icon-minus
+                = diff.old_path
+          - elsif diff.renamed_file
+            %span.renamed-file
+              %a{href: "#diff-#{i}"}
+                %i.icon-minus
+                = diff.old_path
+                = "->"
+                = diff.new_path
+          - elsif diff.new_file
+            %span.new-file
+              %a{href: "#diff-#{i}"}
+                %i.icon-plus
+                = diff.new_path
+          - else
+            %span.edit-file
+              %a{href: "#diff-#{i}"}
+                %i.icon-adjust
+                = diff.new_path
+
diff --git a/app/views/projects/commits/_diff_warning.html.haml b/app/views/projects/commits/_diff_warning.html.haml
new file mode 100644
index 00000000000..05d516efa11
--- /dev/null
+++ b/app/views/projects/commits/_diff_warning.html.haml
@@ -0,0 +1,19 @@
+.bs-callout.bs-callout-warning
+  %h4
+    Too many changes.
+    .pull-right
+      - unless diff_hard_limit_enabled?
+        = link_to "Reload with full diff", url_for(params.merge(force_show_diff: true)), class: "btn btn-small btn-warning"
+
+      - if current_controller?(:commit) or current_controller?(:merge_requests)
+        - if current_controller?(:commit)
+          = link_to "Plain diff", project_commit_path(@project, @commit, format: :diff), class: "btn btn-warning btn-small"
+          = link_to "Email patch", project_commit_path(@project, @commit, format: :patch), class: "btn btn-warning btn-small"
+        - elsif @merge_request && @merge_request.persisted?
+          = link_to "Plain diff", project_merge_request_path(@project, @merge_request, format: :diff), class: "btn btn-warning btn-small"
+          = link_to "Email patch", project_merge_request_path(@project, @merge_request, format: :patch), class: "btn btn-warning btn-small"
+  %p
+    To preserve performance only
+    %strong #{safe_diff_files(diffs).size} of #{diffs.size}
+    files displayed.
+
diff --git a/app/views/projects/commits/_diffs.html.haml b/app/views/projects/commits/_diffs.html.haml
index fcdb40468d9..64d6a2f09cf 100644
--- a/app/views/projects/commits/_diffs.html.haml
+++ b/app/views/projects/commits/_diffs.html.haml
@@ -1,91 +1,23 @@
-- @suppress_diff ||= @suppress_diff || @force_suppress_diff
-- if @suppress_diff
-  .alert.alert-warning
-    %p
-      %strong Warning! This is a large diff.
-    %p
-      To preserve performance the diff is not shown.
-      - if current_controller?(:commit) or current_controller?(:merge_requests)
-        - if current_controller?(:commit)
-          Please, download the diff as
-          = link_to "plain diff", project_commit_path(@project, @commit, format: :diff), class: "underlined-link"
-          or
-          = link_to "email patch", project_commit_path(@project, @commit, format: :patch), class: "underlined-link"
-          instead.
-        - elsif @merge_request && @merge_request.persisted?
-          Please, download the diff as
-          = link_to "plain diff", project_merge_request_path(@project, @merge_request, format: :diff), class: "underlined-link"
-          or
-          = link_to "email patch", project_merge_request_path(@project, @merge_request, format: :patch), class: "underlined-link"
-          instead.
-    - unless @force_suppress_diff
-      %p
-        If you still want to see the diff
-        = link_to "click this link", url_for(force_show_diff: true), class: "underlined-link"
-
-%p.commit-stat-summary
-  Showing
-  %strong.cdark #{pluralize(diffs.count, "changed file")}
-  - if current_controller?(:commit)
-    - unless @commit.has_zero_stats?
-      with
-      %strong.cgreen #{@commit.stats.additions} additions
-      and
-      %strong.cred #{@commit.stats.deletions} deletions
-  - if params[:view] == 'parallel'
-    = link_to "Inline Diff", url_for(view: 'inline'), {id: "commit-diff-viewtype", class: 'btn btn-tiny pull-right'}
-  - else
-    = link_to "Side-by-side Diff", url_for(view: 'parallel'), {id: "commit-diff-viewtype", class: 'btn btn-tiny pull-right'}
-.file-stats
-  = render "projects/commits/diff_head", diffs: diffs
+.row
+  .col-md-8
+    = render 'projects/commits/diff_stats', diffs: diffs
+  .col-md-4
+    %ul.nav.nav-tabs
+      %li.pull-right{class: params[:view] == 'parallel' ? 'active' : ''}
+        = link_to "Side-by-side Diff", url_for(view: 'parallel'), {id: "commit-diff-viewtype"}
+      %li.pull-right{class: params[:view] != 'parallel' ? 'active' : ''}
+        = link_to "Inline Diff", url_for(view: 'inline'), {id: "commit-diff-viewtype"}
+
+- if show_diff_size_warninig?(diffs)
+  = render 'projects/commits/diff_warning', diffs: diffs
 
 .files
-  - unless @suppress_diff
-    - diffs.each_with_index do |diff, i|
-      - file = project.repository.blob_at(@commit.id, diff.new_path)
-      - file = project.repository.blob_at(@commit.parent_id, diff.old_path) unless file
-      - next unless file
-      .diff-file{id: "diff-#{i}"}
-        .diff-header{id: "file-path-#{hexdigest(diff.new_path || diff.old_path)}"}
-          - if diff.deleted_file
-            %span= diff.old_path
-
-            .diff-btn-group
-              - if @commit.parent_ids.present?
-                = link_to project_blob_path(project, tree_join(@commit.parent_id, diff.new_path)), { class: 'btn btn-small view-file' } do
-                  View file @
-                  %span.commit-short-id= @commit.short_id(6)
-          - else
-            %span= diff.new_path
-            - if diff_file_mode_changed?(diff)
-              %span.file-mode= "#{diff.a_mode} → #{diff.b_mode}"
-
-            .diff-btn-group
-              = link_to "#", class: "js-toggle-diff-comments btn btn-small" do
-                %i.icon-chevron-down
-                Diff comments
-              &nbsp;
+  - safe_diff_files(diffs).each_with_index do |diff, i|
+    = render 'projects/commits/diff_file', diff: diff, i: i, project: project
 
-              - if @merge_request && @merge_request.source_project
-                = link_to project_edit_tree_path(@merge_request.source_project, tree_join(@merge_request.source_branch, diff.new_path), from_merge_request_id: @merge_request.id), { class: 'btn btn-small' } do
-                  Edit
-                &nbsp;
-
-              = link_to project_blob_path(project, tree_join(@commit.id, diff.new_path)), { class: 'btn btn-small view-file' } do
-                View file @
-                %span.commit-short-id= @commit.short_id(6)
-
-
-        .diff-content
-          -# Skipp all non non-supported blobs
-          - next unless file.respond_to?('text?')
-          - if file.text?
-            - if params[:view] == 'parallel'
-              = render "projects/commits/parallel_view", diff: diff, project: project, file: file, index: i
-            - else
-              = render "projects/commits/text_file", diff: diff, index: i
-          - elsif file.image?
-            - old_file = project.repository.blob_at(@commit.parent_id, diff.old_path) if @commit.parent_id
-            = render "projects/commits/image", diff: diff, old_file: old_file, file: file, index: i
-          - else
-            .nothing-here-block No preview for this file type
+- if @diff_timeout
+  .alert.alert-danger
+    %h4
+      Failed to collect changes
+    %p
+      Maybe diff is really big and operation failed with timeout. Try to get diff localy
diff --git a/app/views/projects/commits/_text_file.html.haml b/app/views/projects/commits/_text_file.html.haml
index 8ced4133294..f5b0d711416 100644
--- a/app/views/projects/commits/_text_file.html.haml
+++ b/app/views/projects/commits/_text_file.html.haml
@@ -1,4 +1,4 @@
-- too_big = diff.diff.lines.count > 1000
+- too_big = diff.diff.lines.count > Commit::DIFF_SAFE_LINES
 - if too_big
   %a.supp_diff_link Changes suppressed. Click to show
 
diff --git a/app/views/projects/compare/show.html.haml b/app/views/projects/compare/show.html.haml
index b232d2a6b26..240bfe7484e 100644
--- a/app/views/projects/compare/show.html.haml
+++ b/app/views/projects/compare/show.html.haml
@@ -18,18 +18,7 @@
     - else
       %ul.well-list= render Commit.decorate(@commits), project: @project
 
-  %h4 Changes
-  - if @diffs.present?
-    = render "projects/commits/diffs", diffs: @diffs, project: @project
-  - elsif @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
-    .bs-callout.bs-callout-danger
-      %h4 This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
-      %p To preserve performance the line changes are not shown.
-  - elsif @timeout
-    .bs-callout.bs-callout-danger
-      %h4 Number of changed files for this comparison is extremely large.
-      %p Use command line to browse through changes for this comparison.
-
+  = render "projects/commits/diffs", diffs: @diffs, project: @project
 
 - else
   .light-well
diff --git a/app/views/projects/merge_requests/_new_compare.html.haml b/app/views/projects/merge_requests/_new_compare.html.haml
index 18e3f419c72..99726172154 100644
--- a/app/views/projects/merge_requests/_new_compare.html.haml
+++ b/app/views/projects/merge_requests/_new_compare.html.haml
@@ -27,13 +27,13 @@
         .panel-footer
           .mr_target_commit
 
-  -if @merge_request.errors.any?
+  - if @merge_request.errors.any?
     .alert.alert-danger
       - @merge_request.errors.full_messages.each do |msg|
         %div= msg
 
-  - if @merge_request.source_branch.present? && @merge_request.target_branch.present?
-    - if @compare_failed
+  - elsif @merge_request.source_branch.present? && @merge_request.target_branch.present?
+    - if @merge_request.compare_failed
       .alert.alert-danger
         %h4 Compare failed
         %p We can't compare selected branches. It may be because of huge diff or satellite timeout. Please try again or select different branches.
diff --git a/app/views/projects/merge_requests/_new_submit.html.haml b/app/views/projects/merge_requests/_new_submit.html.haml
index 6050f20d763..73d364b4f93 100644
--- a/app/views/projects/merge_requests/_new_submit.html.haml
+++ b/app/views/projects/merge_requests/_new_submit.html.haml
@@ -10,75 +10,75 @@
 
   %span.pull-right
     = link_to 'Change branches', new_project_merge_request_path(@project)
-- if @error.present?
-  .centered-light-block
-    %h4 #{@error}
-- else
-  = form_for [@project, @merge_request], html: { class: "merge-request-form" } do |f|
-    .panel.panel-default
 
-      .panel-body
-        .form-group
-          .light
-            = f.label :title do
-              = "Title *"
-          = f.text_field :title, class: "form-control input-lg js-gfm-input", maxlength: 255, rows: 5, required: true
-        .form-group
-          .light
-            = f.label :description, "Description"
-          = f.text_area :description, class: "form-control js-gfm-input markdown-area", rows: 10
-          .clearfix.hint
-            .pull-left Description is parsed with #{link_to "GitLab Flavored Markdown", help_page_path("markdown", "markdown"), target: '_blank'}.
-            .pull-right Attach images (JPG, PNG, GIF) by dragging & dropping or #{link_to "selecting them", '#', class: 'markdown-selector' }.
-          .error-alert
-        .form-group
-          .issue-assignee
-            = f.label :assignee_id do
-              %i.icon-user
-              Assign to
-            %div
-              = project_users_select_tag('merge_request[assignee_id]', placeholder: 'Select a user', class: 'custom-form-control', selected: @merge_request.assignee_id, project_id: @merge_request.target_project_id)
-              &nbsp;
-              = link_to 'Assign to me', '#', class: 'btn assign-to-me-link'
-        .form-group
-          .issue-milestone
-            = f.label :milestone_id do
-              %i.icon-time
-              Milestone
-            %div= f.select(:milestone_id, milestone_options(@merge_request), { include_blank: "Select milestone" }, {class: 'select2'})
-      .panel-footer
-        - if @target_repo.contribution_guide
-          - contribution_guide_url = project_blob_path(@target_project, tree_join(@target_repo.root_ref, @target_repo.contribution_guide.name))
-          %p
-            Please review the
-            %strong #{link_to "guidelines for contribution", contribution_guide_url}
-            to this repository.
-        = f.hidden_field :source_project_id
-        = f.hidden_field :target_project_id
-        = f.hidden_field :target_branch
-        = f.hidden_field :source_branch
-        = f.submit 'Submit merge request', class: "btn btn-create"
+= form_for [@project, @merge_request], html: { class: "merge-request-form" } do |f|
+  .panel.panel-default
 
-  .mr-compare
-    %div.panel.panel-default
-      .panel-heading
-        Commits (#{@commits.count})
-      - if @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
-        %ul.well-list
-          - Commit.decorate(@commits.first(MergeRequestDiff::COMMITS_SAFE_SIZE)).each do |commit|
-            = render "projects/commits/inline_commit", commit: commit, project: @project
-          %li.warning-row.unstyled
-            other #{@commits.size - MergeRequestDiff::COMMITS_SAFE_SIZE} commits hidden to prevent performance issues.
-      - else
-        %ul.well-list= render Commit.decorate(@commits), project: @project
+    .panel-body
+      .form-group
+        .light
+          = f.label :title do
+            = "Title *"
+        = f.text_field :title, class: "form-control input-lg js-gfm-input", maxlength: 255, rows: 5, required: true
+      .form-group
+        .light
+          = f.label :description, "Description"
+        = f.text_area :description, class: "form-control js-gfm-input markdown-area", rows: 10
+        .clearfix.hint
+          .pull-left Description is parsed with #{link_to "GitLab Flavored Markdown", help_page_path("markdown", "markdown"), target: '_blank'}.
+          .pull-right Attach images (JPG, PNG, GIF) by dragging & dropping or #{link_to "selecting them", '#', class: 'markdown-selector' }.
+        .error-alert
+      .form-group
+        .issue-assignee
+          = f.label :assignee_id do
+            %i.icon-user
+            Assign to
+          %div
+            = project_users_select_tag('merge_request[assignee_id]', placeholder: 'Select a user', class: 'custom-form-control', selected: @merge_request.assignee_id, project_id: @merge_request.target_project_id)
+            &nbsp;
+            = link_to 'Assign to me', '#', class: 'btn assign-to-me-link'
+      .form-group
+        .issue-milestone
+          = f.label :milestone_id do
+            %i.icon-time
+            Milestone
+          %div= f.select(:milestone_id, milestone_options(@merge_request), { include_blank: "Select milestone" }, {class: 'select2'})
+    .panel-footer
+      - if contribution_guide_url(@target_project)
+        %p
+          Please review the
+          %strong #{link_to "guidelines for contribution", contribution_guide_url(@target_project)}
+          to this repository.
+      = f.hidden_field :source_project_id
+      = f.hidden_field :target_project_id
+      = f.hidden_field :target_branch
+      = f.hidden_field :source_branch
+      = f.submit 'Submit merge request', class: "btn btn-create"
 
-    %h4 Changes
-    - if @diffs.present?
-      = render "projects/commits/diffs", diffs: @diffs, project: @project
-    - elsif @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
-      .bs-callout.bs-callout-danger
-        %h4 This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
-        %p To preserve performance the line changes are not shown.
+.mr-compare
+  %div.panel.panel-default
+    .panel-heading
+      Commits (#{@commits.count})
+    - if @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
+      %ul.well-list
+        - Commit.decorate(@commits.first(MergeRequestDiff::COMMITS_SAFE_SIZE)).each do |commit|
+          = render "projects/commits/inline_commit", commit: commit, project: @project
+        %li.warning-row.unstyled
+          other #{@commits.size - MergeRequestDiff::COMMITS_SAFE_SIZE} commits hidden to prevent performance issues.
+    - else
+      %ul.well-list= render Commit.decorate(@commits), project: @project
+
+  %h4 Changes
+  - if @diffs.present?
+    = render "projects/commits/diffs", diffs: @diffs, project: @project
+  - elsif @commits.size > MergeRequestDiff::COMMITS_SAFE_SIZE
+    .bs-callout.bs-callout-danger
+      %h4 This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
+      %p To preserve performance the line changes are not shown.
+  - else
+    .bs-callout.bs-callout-danger
+      %h4 This comparison includes huge diff.
+      %p To preserve performance the line changes are not shown.
 
 
 :javascript
diff --git a/app/views/projects/merge_requests/new.html.haml b/app/views/projects/merge_requests/new.html.haml
index c24e5916721..4756903d0e0 100644
--- a/app/views/projects/merge_requests/new.html.haml
+++ b/app/views/projects/merge_requests/new.html.haml
@@ -1,4 +1,4 @@
-- if @commits.present?
+- if @merge_request.can_be_created
   = render 'new_submit'
 - else
   = render 'new_compare'
diff --git a/config/gitlab.yml.example b/config/gitlab.yml.example
index e0afdc0400e..b044aef9157 100644
--- a/config/gitlab.yml.example
+++ b/config/gitlab.yml.example
@@ -226,7 +226,7 @@ production: &base
     # The next value is the maximum memory size grit can use
     # Given in number of bytes per git object (e.g. a commit)
     # This value can be increased if you have very large commits
-    max_size: 5242880 # 5.megabytes
+    max_size: 15242880 # 15.megabytes
     # Git timeout to read a commit, in seconds
     timeout: 10
 
diff --git a/features/steps/project/browse_commits.rb b/features/steps/project/browse_commits.rb
index bd944dee610..fe47a731915 100644
--- a/features/steps/project/browse_commits.rb
+++ b/features/steps/project/browse_commits.rb
@@ -61,8 +61,7 @@ class ProjectBrowseCommits < Spinach::FeatureSteps
 
   Then 'I see big commit warning' do
     page.should have_content BigCommits::BIG_COMMIT_MESSAGE
-    page.should have_content "Warning! This is a large diff"
-    page.should have_content "If you still want to see the diff"
+    page.should have_content "Too many changes"
   end
 
   Given 'I visit huge commit page' do
@@ -71,8 +70,6 @@ class ProjectBrowseCommits < Spinach::FeatureSteps
 
   Then 'I see huge commit message' do
     page.should have_content BigCommits::HUGE_COMMIT_MESSAGE
-    page.should have_content "Warning! This is a large diff"
-    page.should_not have_content "If you still want to see the diff"
   end
 
   Given 'I visit a commit with an image that changed' do