Merge branch '18019-fix-wiki-linking' into 'master'

Fix wiki linking behavior for markdown wiki pages

Related to #18019 

- As per the documentation in !4372 

## TODO
- [ ] !4432 Have wiki linking behave as per the documentation
    - [x] Move `WikiLinkFilter` specs to the pipeline level
    - [x] Verify current behavior on wiki `show` page
    - [x] Fix current behavior on wiki `show` page
    - [x] Verify current behaviour on wiki preview
    - [x] Fix current behaviour on wiki preview
        - [x] Rewrite all links and get preview links working
        - [x] Make sure all links are on-par with the wiki `show` page
        - [x] TDD `WikiLinkFilter` and get it working
        - [x] Hook `WikiLinkFilter` up
    - [x] Fix tests 
        - [x] Fix `markdown_spec`
        - [x] Fix `wiki` spinach feature
        - [x] Wait for [build](https://gitlab.com/gitlab-org/gitlab-ce/commit/4f50dd2/builds) to pass
        - [x] Make sure all wiki-related pages are working as expected (history, all pages, etc.)
    - [x] Test in different ruby versions
    - [x] GitLab instances hosted on a relative URL
    - [x] Non-markdown rendering formats?
        - [x] RDoc
        - [x] ASCIIDoc
        - [x] Create issues to fix things for RDoc and ASCIIDoc
    - [x] Gauge performance impact
    - [x] Refactor
    - [x] Re-organize commits
    - [x] Make sure [build](https://gitlab.com/gitlab-org/gitlab-ce/commit/f860e9a8dcabe7d5f160c32fc549807c98baa4a1/builds) passes
    - [x] Respond to @rymai's comments
        - [x] `class WikiLinkFilter < HTML::Pipeline::Filter`
        - [x] blank line after guard clause
        - [x] keyword arguments for `wiki` and `slug`
        - [x] invert the condition
        - [x] inline `user` in spec
        - [x] Make sure spec names are not out of date
        - [x] Comment for each rewrite rule
    - [x] Add CHANGELOG entry
    - [x] Reorganize commits
    - [x] Make sure [build](https://gitlab.com/gitlab-org/gitlab-ce/commit/19b91e749a6320d12fb299d33f1f6440777e0e26/builds) passes
    - [ ] Wait for merge

See merge request !4432

6 files changed, 117 insertions, 88 deletions

diff --git a/spec/factories/wiki_pages.rb b/spec/factories/wiki_pages.rb
index 938ccf2306b..efa6cbe5bb1 100644
--- a/spec/factories/wiki_pages.rb
+++ b/spec/factories/wiki_pages.rb
@@ -2,7 +2,7 @@ require 'ostruct'
 
 FactoryGirl.define do
   factory :wiki_page do
-    page = OpenStruct.new(url_path: 'some-name')
+    page { OpenStruct.new(url_path: 'some-name') }
     association :wiki, factory: :project_wiki, strategy: :build
     initialize_with { new(wiki, page, true) }
   end
diff --git a/spec/features/markdown_spec.rb b/spec/features/markdown_spec.rb
index 1193cae5a2f..09ccc77c101 100644
--- a/spec/features/markdown_spec.rb
+++ b/spec/features/markdown_spec.rb
@@ -241,13 +241,14 @@ describe 'GitLab Markdown', feature: true do
   context 'wiki pipeline' do
     before do
       @project_wiki = @feat.project_wiki
+      @project_wiki_page = @feat.project_wiki_page
 
       file = Gollum::File.new(@project_wiki.wiki)
       expect(file).to receive(:path).and_return('images/example.jpg')
       expect(@project_wiki).to receive(:find_file).with('images/example.jpg').and_return(file)
       allow(@project_wiki).to receive(:wiki_base_path) { '/namespace1/gitlabhq/wikis' }
 
-      @html = markdown(@feat.raw_markdown, { pipeline: :wiki, project_wiki: @project_wiki })
+      @html = markdown(@feat.raw_markdown, { pipeline: :wiki, project_wiki: @project_wiki, page_slug: @project_wiki_page.slug })
     end
 
     it_behaves_like 'all pipelines'
diff --git a/spec/helpers/gitlab_markdown_helper_spec.rb b/spec/helpers/gitlab_markdown_helper_spec.rb
index 13de88e2f21..ade5c3b02d9 100644
--- a/spec/helpers/gitlab_markdown_helper_spec.rb
+++ b/spec/helpers/gitlab_markdown_helper_spec.rb
@@ -121,13 +121,14 @@ describe GitlabMarkdownHelper do
     before do
       @wiki = double('WikiPage')
       allow(@wiki).to receive(:content).and_return('wiki content')
+      allow(@wiki).to receive(:slug).and_return('nested/page')
       helper.instance_variable_set(:@project_wiki, @wiki)
     end
 
     it "should use Wiki pipeline for markdown files" do
       allow(@wiki).to receive(:format).and_return(:markdown)
 
-      expect(helper).to receive(:markdown).with('wiki content', pipeline: :wiki, project_wiki: @wiki)
+      expect(helper).to receive(:markdown).with('wiki content', pipeline: :wiki, project_wiki: @wiki, page_slug: "nested/page")
 
       helper.render_wiki_content(@wiki)
     end
diff --git a/spec/lib/banzai/filter/wiki_link_filter_spec.rb b/spec/lib/banzai/filter/wiki_link_filter_spec.rb
deleted file mode 100644
index 185abbb2108..00000000000
--- a/spec/lib/banzai/filter/wiki_link_filter_spec.rb
+++ /dev/null
@@ -1,85 +0,0 @@
-require 'spec_helper'
-
-describe Banzai::Filter::WikiLinkFilter, lib: true do
-  include FilterSpecHelper
-
-  let(:namespace) { build_stubbed(:namespace, name: "wiki_link_ns") }
-  let(:project)   { build_stubbed(:empty_project, :public, name: "wiki_link_project", namespace: namespace) }
-  let(:user) { double }
-  let(:project_wiki) { ProjectWiki.new(project, user) }
-
-  describe "links within the wiki (relative)" do
-    describe "hierarchical links to the current directory" do
-      it "doesn't rewrite non-file links" do
-        link = "<a href='./page'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('./page')
-      end
-
-      it "doesn't rewrite file links" do
-        link = "<a href='./page.md'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('./page.md')
-      end
-    end
-
-    describe "hierarchical links to the parent directory" do
-      it "doesn't rewrite non-file links" do
-        link = "<a href='../page'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('../page')
-      end
-
-      it "doesn't rewrite file links" do
-        link = "<a href='../page.md'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('../page.md')
-      end
-    end
-
-    describe "hierarchical links to a sub-directory" do
-      it "doesn't rewrite non-file links" do
-        link = "<a href='./subdirectory/page'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('./subdirectory/page')
-      end
-
-      it "doesn't rewrite file links" do
-        link = "<a href='./subdirectory/page.md'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('./subdirectory/page.md')
-      end
-    end
-
-    describe "non-hierarchical links" do
-      it 'rewrites non-file links to be at the scope of the wiki root' do
-        link = "<a href='page'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to match('/wiki_link_ns/wiki_link_project/wikis/page')
-      end
-
-      it "doesn't rewrite file links" do
-        link = "<a href='page.md'>Link to Page</a>"
-        filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-        expect(filtered_link.attribute('href').value).to eq('page.md')
-      end
-    end
-  end
-
-  describe "links outside the wiki (absolute)" do
-    it "doesn't rewrite links" do
-      link = "<a href='http://example.com/page'>Link to Page</a>"
-      filtered_link = filter(link, project_wiki: project_wiki).children[0]
-
-      expect(filtered_link.attribute('href').value).to eq('http://example.com/page')
-    end
-  end
-end
diff --git a/spec/lib/banzai/pipeline/wiki_pipeline_spec.rb b/spec/lib/banzai/pipeline/wiki_pipeline_spec.rb
index 7aa1b4a3bf6..ea4ab2c852e 100644
--- a/spec/lib/banzai/pipeline/wiki_pipeline_spec.rb
+++ b/spec/lib/banzai/pipeline/wiki_pipeline_spec.rb
@@ -50,4 +50,112 @@ describe Banzai::Pipeline::WikiPipeline do
       end
     end
   end
+
+  describe "Links" do
+    let(:namespace) { build_stubbed(:namespace, name: "wiki_link_ns") }
+    let(:project)   { build_stubbed(:empty_project, :public, name: "wiki_link_project", namespace: namespace) }
+    let(:project_wiki) { ProjectWiki.new(project, double(:user)) }
+    let(:page) { build(:wiki_page, wiki: project_wiki, page: OpenStruct.new(url_path: 'nested/twice/start-page')) }
+
+    { "when GitLab is hosted at a root URL" => '/',
+      "when GitLab is hosted at a relative URL" => '/nested/relative/gitlab' }.each do |test_name, relative_url_root|
+
+      context test_name do
+        before do
+          allow(Gitlab.config.gitlab).to receive(:relative_url_root).and_return(relative_url_root)
+        end
+
+        describe "linking to pages within the wiki" do
+          context "when creating hierarchical links to the current directory" do
+            it "rewrites non-file links to be at the scope of the current directory" do
+              markdown = "[Page](./page)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/twice/page\"")
+            end
+
+            it "rewrites file links to be at the scope of the current directory" do
+              markdown = "[Link to Page](./page.md)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/twice/page.md\"")
+            end
+          end
+
+          context "when creating hierarchical links to the parent directory" do
+            it "rewrites non-file links to be at the scope of the parent directory" do
+              markdown = "[Link to Page](../page)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/page\"")
+            end
+
+            it "rewrites file links to be at the scope of the parent directory" do
+              markdown = "[Link to Page](../page.md)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/page.md\"")
+            end
+          end
+
+          context "when creating hierarchical links to a sub-directory" do
+            it "rewrites non-file links to be at the scope of the sub-directory" do
+              markdown = "[Link to Page](./subdirectory/page)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/twice/subdirectory/page\"")
+            end
+
+            it "rewrites file links to be at the scope of the sub-directory" do
+              markdown = "[Link to Page](./subdirectory/page.md)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/twice/subdirectory/page.md\"")
+            end
+          end
+
+          describe "when creating non-hierarchical links" do
+            it 'rewrites non-file links to be at the scope of the wiki root' do
+              markdown = "[Link to Page](page)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/page\"")
+            end
+
+            it "rewrites file links to be at the scope of the current directory" do
+              markdown = "[Link to Page](page.md)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/nested/twice/page.md\"")
+            end
+          end
+
+          describe "when creating root links" do
+            it 'rewrites non-file links to be at the scope of the wiki root' do
+              markdown = "[Link to Page](/page)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/page\"")
+            end
+
+            it 'rewrites file links to be at the scope of the wiki root' do
+              markdown = "[Link to Page](/page.md)"
+              output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+              expect(output).to include("href=\"#{relative_url_root}/wiki_link_ns/wiki_link_project/wikis/page.md\"")
+            end
+          end
+        end
+
+        describe "linking to pages outside the wiki (absolute)" do
+          it "doesn't rewrite links" do
+            markdown = "[Link to Page](http://example.com/page)"
+            output = described_class.to_html(markdown, project: project, project_wiki: project_wiki, page_slug: page.slug)
+
+            expect(output).to include('href="http://example.com/page"')
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/support/markdown_feature.rb b/spec/support/markdown_feature.rb
index 7fc6d6fcc5e..a79386b5db9 100644
--- a/spec/support/markdown_feature.rb
+++ b/spec/support/markdown_feature.rb
@@ -32,6 +32,10 @@ class MarkdownFeature
     @project_wiki ||= ProjectWiki.new(project, user)
   end
 
+  def project_wiki_page
+    @project_wiki_page ||= build(:wiki_page, wiki: project_wiki)
+  end
+
   def issue
     @issue ||= create(:issue, project: project)
   end