Fix Web IDE deleting newly added files

*How?*
It does this by removing from stagedFiles as
well as changedFiles. This is not ideal and should
be addressed in [this issue][1].

[1]: https://gitlab.com/gitlab-org/create-stage/-/issues/12669

app/assets/javascripts/ide/stores/mutations.js

@@ -216,7 +216,12 @@ export default {
 
     if (entry.type === 'blob') {
       if (tempFile) {
+        // Since we only support one list of file changes, it's safe to just remove from both
+        // changed and staged. Otherwise, we'd need to somehow evaluate the difference between
+        // changed and HEAD.
+        // https://gitlab.com/gitlab-org/create-stage/-/issues/12669
         state.changedFiles = state.changedFiles.filter(f => f.path !== path);
+        state.stagedFiles = state.stagedFiles.filter(f => f.path !== path);
       } else {
         state.changedFiles = state.changedFiles.concat(entry);
       }

changelogs/unreleased/213239-fix-newly-added-deleted-files-in-ide.yml

+---
+title: Fix Web IDE handling of deleting newly added files
+merge_request: 29783
+author:
+type: fixed

spec/features/ide/user_commits_changes_spec.rb

@@ -30,4 +30,14 @@ describe 'IDE user commits changes', :js do
     expect(project.repository.blob_at('master', 'foo/bar/.gitkeep')).to be_nil
     expect(project.repository.blob_at('master', 'foo/bar/lorem_ipsum.md').data).to eql(content)
   end
+
+  it 'user adds then deletes new file' do
+    ide_create_new_file('foo/bar/lorem_ipsum.md')
+
+    expect(page).to have_selector(ide_commit_tab_selector)
+
+    ide_delete_file('foo/bar/lorem_ipsum.md')
+
+    expect(page).not_to have_selector(ide_commit_tab_selector)
+  end
 end

spec/frontend/ide/stores/mutations_spec.js

@@ -273,7 +273,7 @@ describe('Multi-file store mutations', () => {
       expect(localState.changedFiles).toEqual([]);
     });
 
-    it('removes tempFile from changedFiles when deleted', () => {
+    it('removes tempFile from changedFiles and stagedFiles when deleted', () => {
       localState.entries.filePath = {
         path: 'filePath',
         deleted: false,
@@ -282,10 +282,12 @@ describe('Multi-file store mutations', () => {
       };
 
       localState.changedFiles.push({ ...localState.entries.filePath });
+      localState.stagedFiles.push({ ...localState.entries.filePath });
 
       mutations.DELETE_ENTRY(localState, 'filePath');
 
       expect(localState.changedFiles).toEqual([]);
+      expect(localState.stagedFiles).toEqual([]);
     });
 
     it('bursts unused seal', () => {

spec/support/helpers/features/web_ide_spec_helpers.rb

@@ -32,6 +32,10 @@ module WebIdeSpecHelpers
     page.find('.ide-tree-actions')
   end
 
+  def ide_tab_selector(mode)
+    ".js-ide-#{mode}-mode"
+  end
+
   def ide_file_row_open?(row)
     row.matches_css?('.is-open')
   end
@@ -106,16 +110,16 @@ module WebIdeSpecHelpers
     evaluate_script("monaco.editor.getModel('#{uri}').getValue()")
   end
 
+  def ide_commit_tab_selector
+    ide_tab_selector('commit')
+  end
+
   def ide_commit
-    ide_switch_mode('commit')
+    find(ide_commit_tab_selector).click
 
     commit_to_current_branch
   end
 
-  def ide_switch_mode(mode)
-    find(".js-ide-#{mode}-mode").click
-  end
-
   private
 
   def file_row_container(row)