Support wildcard with double asterisks for CI file includes

app/models/repository.rb

@@ -995,7 +995,13 @@ class Repository
 
   def search_files_by_wildcard_path(path, ref = 'HEAD')
     # We need to use RE2 to match Gitaly's regexp engine
-    regexp_string = RE2::Regexp.escape(path).gsub('\*', '.*?')
+    regexp_string = RE2::Regexp.escape(path)
+
+    anything = '.*?'
+    anything_but_not_slash = '([^\/])*?'
+    regexp_string.gsub!('\*\*', anything)
+    regexp_string.gsub!('\*', anything_but_not_slash)
+
     raw_repository.search_files_by_regexp("^#{regexp_string}$", ref)
   end
 

doc/ci/yaml/README.md

@@ -487,7 +487,7 @@ Use local includes instead of symbolic links.
 > - It's not recommended for production use.
 > - To use it in GitLab self-managed instances, ask a GitLab administrator to enable it. **(CORE ONLY)**
 
-You can use wildcard paths (`*`) with `include:local`.
+You can use wildcard paths (`*` and `**`) with `include:local`.
 
 Example:
 
@@ -495,7 +495,19 @@ Example:
 include: 'configs/*.yml'
 ```
 
-When the pipeline runs, it adds all `.yml` files in the `configs` folder into the pipeline configuration.
+When the pipeline runs, GitLab:
+
+- Adds all `.yml` files in the `configs` directory into the pipeline configuration.
+- Does not add `.yml` files in subfolders of the `configs` directory. To allow this,
+  add the following configuration:
+
+  ```yaml
+  # This matches all `.yml` files in `configs` and any subfolder in it.
+  include: 'configs/**.yml'
+
+  # This matches all `.yml` files only in subfolders of `configs`.
+  include: 'configs/**/*.yml'
+  ```
 
 The wildcard file paths feature is under development and not ready for production use. It is
 deployed behind a feature flag that is **disabled by default**.

spec/models/repository_spec.rb

@@ -1006,19 +1006,58 @@ RSpec.describe Repository do
       end
     end
 
-    context 'when specifying a path with wildcard' do
-      let(:path) { 'files/*/*.png' }
+    context 'when specifying a wildcard path' do
+      let(:path) { '*.md' }
+
+      it 'returns files matching the path in the root folder' do
+        expect(result).to contain_exactly('CONTRIBUTING.md',
+                                          'MAINTENANCE.md',
+                                          'PROCESS.md',
+                                          'README.md')
+      end
+    end
+
+    context 'when specifying a wildcard path for all' do
+      let(:path) { '**.md' }
+
+      it 'returns all matching files in all folders' do
+        expect(result).to contain_exactly('CONTRIBUTING.md',
+                                          'MAINTENANCE.md',
+                                          'PROCESS.md',
+                                          'README.md',
+                                          'files/markdown/ruby-style-guide.md',
+                                          'with space/README.md')
+      end
+    end
+
+    context 'when specifying a path to subfolders using two asterisks and a slash' do
+      let(:path) { 'files/**/*.md' }
 
       it 'returns all files matching the path' do
-        expect(result).to contain_exactly('files/images/logo-black.png',
-                                          'files/images/logo-white.png')
+        expect(result).to contain_exactly('files/markdown/ruby-style-guide.md')
+      end
+    end
+
+    context 'when specifying a wildcard path to subfolder with just two asterisks' do
+      let(:path) { 'files/**.md' }
+
+      it 'returns all files in the matching path' do
+        expect(result).to contain_exactly('files/markdown/ruby-style-guide.md')
+      end
+    end
+
+    context 'when specifying a wildcard path to subfolder with one asterisk' do
+      let(:path) { 'files/*/*.md' }
+
+      it 'returns all files in the matching path' do
+        expect(result).to contain_exactly('files/markdown/ruby-style-guide.md')
       end
     end
 
-    context 'when specifying an extension with wildcard' do
-      let(:path) { '*.rb' }
+    context 'when specifying a wildcard path for an unknown number of subfolder levels' do
+      let(:path) { '**/*.rb' }
 
-      it 'returns all files matching the extension' do
+      it 'returns all matched files in all subfolders' do
         expect(result).to contain_exactly('encoding/russian.rb',
                                           'files/ruby/popen.rb',
                                           'files/ruby/regex.rb',
@@ -1026,6 +1065,14 @@ RSpec.describe Repository do
       end
     end
 
+    context 'when specifying a wildcard path to one level of subfolders' do
+      let(:path) { '*/*.rb' }
+
+      it 'returns all matched files in one subfolder' do
+        expect(result).to contain_exactly('encoding/russian.rb')
+      end
+    end
+
     context 'when sending regexp' do
       let(:path) { '.*\.rb' }