diff --git a/CHANGELOG b/CHANGELOG
index 57ee5361281..80cd8b61e8a 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -92,6 +92,7 @@ v 8.10.0 (unreleased)
   - Add min value for project limit field on user's form !3622 (jastkand)
   - Reset project pushes_since_gc when we enqueue the git gc call
   - Add reminder to not paste private SSH keys !4399 (Ingo Blechschmidt)
+  - Collapsed diffs lines/size don't acumulate to overflow diffs.
   - Remove duplicate `description` field in `MergeRequest` entities (Ben Boeckel)
   - Style of import project buttons were fixed in the new project page. !5183 (rdemirbay)
   - Fix GitHub client requests when rate limit is disabled
diff --git a/Gemfile b/Gemfile
index 81e8ff60ad5..6ae9086a541 100644
--- a/Gemfile
+++ b/Gemfile
@@ -52,7 +52,7 @@ gem 'browser', '~> 2.2'
 
 # Extracting information from a git repository
 # Provide access to Gitlab::Git library
-gem 'gitlab_git', '~> 10.2'
+gem 'gitlab_git', '~> 10.3.2'
 
 # LDAP Auth
 # GitLab fork with several improvements to original library. For full list of changes
diff --git a/Gemfile.lock b/Gemfile.lock
index 0987fd5665a..9ec5fe12820 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -274,7 +274,7 @@ GEM
       diff-lcs (~> 1.1)
       mime-types (>= 1.16, < 3)
       posix-spawn (~> 0.3)
-    gitlab_git (10.2.3)
+    gitlab_git (10.3.2)
       activesupport (~> 4.0)
       charlock_holmes (~> 0.7.3)
       github-linguist (~> 4.7.0)
@@ -861,7 +861,7 @@ DEPENDENCIES
   github-linguist (~> 4.7.0)
   github-markup (~> 1.4)
   gitlab-flowdock-git-hook (~> 1.0.1)
-  gitlab_git (~> 10.2)
+  gitlab_git (~> 10.3.2)
   gitlab_meta (= 7.0)
   gitlab_omniauth-ldap (~> 1.2.1)
   gollum-lib (~> 4.2)
diff --git a/app/controllers/concerns/diff_for_path.rb b/app/controllers/concerns/diff_for_path.rb
index e09b8789eb2..026d8b2e1e0 100644
--- a/app/controllers/concerns/diff_for_path.rb
+++ b/app/controllers/concerns/diff_for_path.rb
@@ -10,7 +10,6 @@ module DiffForPath
 
     diff_commit = commit_for_diff(diff_file)
     blob = diff_file.blob(diff_commit)
-    @expand_all_diffs = true
 
     locals = {
       diff_file: diff_file,
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index adab901700c..75b029365f9 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -9,7 +9,7 @@ module DiffHelper
   end
 
   def expand_all_diffs?
-    @expand_all_diffs || params[:expand_all_diffs].present?
+    params[:expand_all_diffs].present?
   end
 
   def diff_view
@@ -23,13 +23,14 @@ module DiffHelper
   end
 
   def diff_options
-    default_options = Commit.max_diff_options
+    options = { ignore_whitespace_change: hide_whitespace?, no_collapse: expand_all_diffs? }
 
     if action_name == 'diff_for_path'
-      default_options[:paths] = params.values_at(:old_path, :new_path)
+      options[:no_collapse] = true
+      options[:paths] = params.values_at(:old_path, :new_path)
     end
 
-    default_options.merge(ignore_whitespace_change: hide_whitespace?)
+    Commit.max_diff_options.merge(options)
   end
 
   def safe_diff_files(diffs, diff_refs: nil, repository: nil)
diff --git a/app/views/projects/diffs/_content.html.haml b/app/views/projects/diffs/_content.html.haml
index 0c0424edffd..a1b071f130c 100644
--- a/app/views/projects/diffs/_content.html.haml
+++ b/app/views/projects/diffs/_content.html.haml
@@ -8,12 +8,12 @@
   - elsif blob_text_viewable?(blob)
     - if !project.repository.diffable?(blob)
       .nothing-here-block This diff was suppressed by a .gitattributes entry.
+    - elsif diff_file.collapsed?
+      - url = url_for(params.merge(action: :diff_for_path, old_path: diff_file.old_path, new_path: diff_file.new_path))
+      .nothing-here-block.diff-collapsed{data: { diff_for_path: url } }
+        This diff is collapsed. Click to expand it.
     - elsif diff_file.diff_lines.length > 0
-      - if diff_file.collapsed_by_default? && !expand_all_diffs?
-        - url = url_for(params.merge(action: :diff_for_path, old_path: diff_file.old_path, new_path: diff_file.new_path))
-        .nothing-here-block.diff-collapsed{data: { diff_for_path: url } }
-          This diff is collapsed. Click to expand it.
-      - elsif diff_view == 'parallel'
+      - if diff_view == 'parallel'
         = render "projects/diffs/parallel_view", diff_file: diff_file, project: project, blob: blob
       - else
         = render "projects/diffs/text_file", diff_file: diff_file
diff --git a/app/views/projects/diffs/_diffs.html.haml b/app/views/projects/diffs/_diffs.html.haml
index 20aaab5accf..8ae433b4823 100644
--- a/app/views/projects/diffs/_diffs.html.haml
+++ b/app/views/projects/diffs/_diffs.html.haml
@@ -6,7 +6,7 @@
 
 .content-block.oneline-block.files-changed
   .inline-parallel-buttons
-    - unless expand_all_diffs?
+    - if !expand_all_diffs? && diff_files.any? { |diff_file| diff_file.collapsed? }
       = link_to 'Expand all', url_for(params.merge(expand_all_diffs: 1, format: 'html')), class: 'btn btn-default'
     - if show_whitespace_toggle
       - if current_controller?(:commit)
diff --git a/lib/gitlab/diff/file.rb b/lib/gitlab/diff/file.rb
index 7e01f7b61fb..b09ca1fb8b0 100644
--- a/lib/gitlab/diff/file.rb
+++ b/lib/gitlab/diff/file.rb
@@ -5,7 +5,7 @@ module Gitlab
 
       delegate :new_file, :deleted_file, :renamed_file,
         :old_path, :new_path, :a_mode, :b_mode,
-        :submodule?, :too_large?, to: :diff, prefix: false
+        :submodule?, :too_large?, :collapsed?, to: :diff, prefix: false
 
       def initialize(diff, repository:, diff_refs: nil)
         @diff = diff
@@ -68,10 +68,6 @@ module Gitlab
         @lines ||= Gitlab::Diff::Parser.new.parse(raw_diff.each_line).to_a
       end
 
-      def collapsed_by_default?
-        diff.diff.bytesize > 10240 # 10 KB
-      end
-
       def highlighted_diff_lines
         @highlighted_diff_lines ||= Gitlab::Diff::Highlight.new(self, repository: self.repository).highlight
       end
diff --git a/spec/features/expand_collapse_diffs_spec.rb b/spec/features/expand_collapse_diffs_spec.rb
index 78bc888f2a6..688f68d3cff 100644
--- a/spec/features/expand_collapse_diffs_spec.rb
+++ b/spec/features/expand_collapse_diffs_spec.rb
@@ -3,10 +3,11 @@ require 'spec_helper'
 feature 'Expand and collapse diffs', js: true, feature: true do
   include WaitForAjax
 
+  let(:branch) { 'expand-collapse-diffs' }
+
   before do
     login_as :admin
     project = create(:project)
-    branch = 'expand-collapse-diffs'
 
     # Ensure that undiffable.md is in .gitattributes
     project.repository.copy_gitattributes(branch)
@@ -167,6 +168,46 @@ feature 'Expand and collapse diffs', js: true, feature: true do
     end
   end
 
+  context 'visiting a commit without collapsed diffs' do
+    let(:branch) { 'feature' }
+
+    it 'does not show Expand all button' do
+      expect(page).not_to have_link('Expand all')
+    end
+  end
+
+  context 'visiting a commit with more than safe files' do
+    let(:branch) { 'expand-collapse-files' }
+
+    # safe-files -> 100 | safe-lines -> 5000 | commit-files -> 105
+    it 'does collapsing from the safe number of files to the end on small files' do
+      expect(page).to have_link('Expand all')
+
+      expect(page).to have_selector('.diff-content', count: 105)
+      expect(page).to have_selector('.diff-collapsed', count: 5)
+
+      %w(file-95.txt file-96.txt file-97.txt file-98.txt file-99.txt).each do |filename|
+        expect(find("[data-blob-diff-path*='#{filename}']")).to have_selector('.diff-collapsed')
+      end
+    end
+  end
+
+  context 'visiting a commit with more than safe lines' do
+    let(:branch) { 'expand-collapse-lines' }
+
+    # safe-files -> 100 | safe-lines -> 5000 | commit_files -> 8 (each 1250 lines)
+    it 'does collapsing from the safe number of lines to the end' do
+      expect(page).to have_link('Expand all')
+
+      expect(page).to have_selector('.diff-content', count: 6)
+      expect(page).to have_selector('.diff-collapsed', count: 2)
+
+      %w(file-4.txt file-5.txt).each do |filename|
+        expect(find("[data-blob-diff-path*='#{filename}']")).to have_selector('.diff-collapsed')
+      end
+    end
+  end
+
   context 'expanding all diffs' do
     before do
       click_link('Expand all')
diff --git a/spec/helpers/diff_helper_spec.rb b/spec/helpers/diff_helper_spec.rb
index 4b134a48410..c2fd2c8a533 100644
--- a/spec/helpers/diff_helper_spec.rb
+++ b/spec/helpers/diff_helper_spec.rb
@@ -30,12 +30,31 @@ describe DiffHelper do
       expect(helper.diff_view).to eq 'inline'
     end
   end
-
+  
   describe 'diff_options' do
-    it 'should return hard limit for a diff' do
+    it 'should return hard limit for a diff if force diff is true' do
       allow(controller).to receive(:params) { { force_show_diff: true } }
       expect(diff_options).to include(Commit.max_diff_options)
     end
+
+    it 'should return hard limit for a diff if expand_all_diffs is true' do
+      allow(controller).to receive(:params) { { expand_all_diffs: true } }
+      expect(diff_options).to include(Commit.max_diff_options)
+    end
+
+    it 'should return no collapse false' do
+      expect(diff_options).to include(no_collapse: false)
+    end
+
+    it 'should return no collapse true if expand_all_diffs' do
+      allow(controller).to receive(:params) { { expand_all_diffs: true } }
+      expect(diff_options).to include(no_collapse: true)
+    end
+
+    it 'should return no collapse true if action name diff_for_path' do
+      allow(controller).to receive(:action_name) { 'diff_for_path' }
+      expect(diff_options).to include(no_collapse: true)
+    end
   end
 
   describe 'unfold_bottom_class' do
diff --git a/spec/lib/gitlab/diff/file_spec.rb b/spec/lib/gitlab/diff/file_spec.rb
index 0460dcf4658..e883a6eb9c2 100644
--- a/spec/lib/gitlab/diff/file_spec.rb
+++ b/spec/lib/gitlab/diff/file_spec.rb
@@ -32,4 +32,18 @@ describe Gitlab::Diff::File, lib: true do
       expect(diff_file.too_large?).to eq(false)
     end
   end
+
+  describe '#collapsed?' do
+    it 'returns true for a file that is quite big' do
+      expect(diff).to receive(:collapsed?).and_return(true)
+
+      expect(diff_file.collapsed?).to eq(true)
+    end
+
+    it 'returns false for a file that is small enough' do
+      expect(diff).to receive(:collapsed?).and_return(false)
+
+      expect(diff_file.collapsed?).to eq(false)
+    end
+  end
 end
diff --git a/spec/support/test_env.rb b/spec/support/test_env.rb
index bb6c84262f6..83f2ad96fd8 100644
--- a/spec/support/test_env.rb
+++ b/spec/support/test_env.rb
@@ -18,7 +18,9 @@ module TestEnv
     'orphaned-branch'       => '45127a9',
     'binary-encoding'       => '7b1cf43',
     'gitattributes'         => '5a62481',
-    'expand-collapse-diffs' => '4842455'
+    'expand-collapse-diffs' => '4842455',
+    'expand-collapse-files' => '025db92',
+    'expand-collapse-lines' => '238e82d'
   }
 
   # gitlab-test-fork is a fork of gitlab-fork, but we don't necessarily