Handle entry not found in changeFileContent action

This fixes some console errors being thrown
because of mystereious monaco race conditions.

app/assets/javascripts/ide/stores/actions/file.js

@@ -166,6 +166,13 @@ export const getRawFileData = ({ state, commit, dispatch, getters }, { path }) =
 
 export const changeFileContent = ({ commit, state, getters }, { path, content }) => {
   const file = state.entries[path];
+
+  // It's possible for monaco to hit a race condition where it tries to update renamed files.
+  // See issue https://gitlab.com/gitlab-org/gitlab/-/issues/284930
+  if (!file) {
+    return;
+  }
+
   commit(types.UPDATE_FILE_CONTENT, {
     path,
     content,

changelogs/unreleased/284930-fix-entry-not-found-change-file-content.yml

+---
+title: Fix console error being thrown when file is renamed
+merge_request: 48275
+author:
+type: fixed

spec/frontend/ide/stores/actions/file_spec.js

@@ -510,8 +510,6 @@ describe('IDE store file actions', () => {
 
   describe('changeFileContent', () => {
     let tmpFile;
-    const callAction = (content = 'content\n') =>
-      store.dispatch('changeFileContent', { path: tmpFile.path, content });
 
     beforeEach(() => {
       tmpFile = file('tmpFile');
@@ -521,11 +519,23 @@ describe('IDE store file actions', () => {
     });
 
     it('updates file content', () => {
-      return callAction().then(() => {
+      const content = 'content\n';
+
+      return store.dispatch('changeFileContent', { path: tmpFile.path, content }).then(() => {
         expect(tmpFile.content).toBe('content\n');
       });
     });
 
+    it('does nothing if path does not exist', () => {
+      const content = 'content\n';
+
+      return store
+        .dispatch('changeFileContent', { path: 'not/a/real_file.txt', content })
+        .then(() => {
+          expect(tmpFile.content).toBe('\n');
+        });
+    });
+
     it('adds file into stagedFiles array', () => {
       return store
         .dispatch('changeFileContent', {