Handle multiple digit auto snippet naming

app/models/snippet_repository.rb

@@ -4,7 +4,7 @@ class SnippetRepository < ApplicationRecord
   include Shardable
 
   DEFAULT_EMPTY_FILE_NAME = 'snippetfile'
-  EMPTY_FILE_PATTERN = /^#{DEFAULT_EMPTY_FILE_NAME}(\d)\.txt$/.freeze
+  EMPTY_FILE_PATTERN = /^#{DEFAULT_EMPTY_FILE_NAME}(\d+)\.txt$/.freeze
 
   CommitError = Class.new(StandardError)
 
@@ -51,14 +51,14 @@ class SnippetRepository < ApplicationRecord
   end
 
   def transform_file_entries(files)
-    last_index = get_last_empty_file_index
+    next_index = get_last_empty_file_index + 1
 
     files.each do |file_entry|
       file_entry[:action] = infer_action(file_entry) unless file_entry[:action]
 
       if file_entry[:file_path].blank?
-        file_entry[:file_path] = build_empty_file_name(last_index)
-        last_index += 1
+        file_entry[:file_path] = build_empty_file_name(next_index)
+        next_index += 1
       end
     end
   end
@@ -70,12 +70,10 @@ class SnippetRepository < ApplicationRecord
   end
 
   def get_last_empty_file_index
-    last_file = repository.ls_files(nil)
-                          .map! { |file| file.match(EMPTY_FILE_PATTERN) }
-                          .compact
-                          .max_by { |element| element[1] }
-
-    last_file ? (last_file[1].to_i + 1) : 1
+    repository.ls_files(nil).inject(0) do |max, file|
+      idx = file[EMPTY_FILE_PATTERN, 1].to_i
+      [idx, max].max
+    end
   end
 
   def build_empty_file_name(index)

spec/models/snippet_repository_spec.rb

@@ -168,34 +168,42 @@ describe SnippetRepository do
       end
     end
 
-    context 'when files are not named' do
-      let(:data) do
-        [
-          {
-            file_path: '',
-            content: 'foo',
-            action: :create
-          },
-          {
-            file_path: '',
-            content: 'bar',
-            action: :create
-          },
-          {
-            file_path: 'foo.txt',
-            content: 'bar',
-            action: :create
-          }
-        ]
+    shared_examples 'snippet repository with file names' do |*filenames|
+      it 'sets a name for unnamed files' do
+        ls_files = snippet.repository.ls_files(nil)
+        expect(ls_files).to include(*filenames)
       end
+    end
+
+    let_it_be(:named_snippet) { { file_path: 'fee.txt', content: 'bar', action: :create } }
+    let_it_be(:unnamed_snippet) { { file_path: '', content: 'dummy', action: :create } }
 
-      it 'sets a name for non named files' do
+    context 'when some files are not named' do
+      let(:data) { [named_snippet] + Array.new(2) { unnamed_snippet.clone } }
+
+      before do
         expect do
           snippet_repository.multi_files_action(user, data, commit_opts)
         end.not_to raise_error
+      end
+
+      it_behaves_like 'snippet repository with file names', 'snippetfile1.txt', 'snippetfile2.txt'
+    end
 
-        expect(snippet.repository.ls_files(nil)).to include('snippetfile1.txt', 'snippetfile2.txt', 'foo.txt')
+    context 'repository already has 10 unnamed snippets' do
+      let(:pre_populate_data) { Array.new(10) { unnamed_snippet.clone } }
+      let(:data) { [named_snippet] + Array.new(2) { unnamed_snippet.clone } }
+
+      before do
+        # Pre-populate repository with 9 unnamed snippets.
+        snippet_repository.multi_files_action(user, pre_populate_data, commit_opts)
+
+        expect do
+          snippet_repository.multi_files_action(user, data, commit_opts)
+        end.not_to raise_error
       end
+
+      it_behaves_like 'snippet repository with file names', 'snippetfile10.txt', 'snippetfile11.txt'
     end
   end