Resolve "It's impossible to commit twice to the same branch"

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

@@ -146,13 +146,7 @@ export default {
       staged: false,
       prevPath: '',
       moved: false,
-      lastCommit: Object.assign(state.entries[file.path].lastCommit, {
-        id: lastCommit.commit.id,
-        url: lastCommit.commit_path,
-        message: lastCommit.commit.message,
-        author: lastCommit.commit.author_name,
-        updatedAt: lastCommit.commit.authored_date,
-      }),
+      lastCommitSha: lastCommit.commit.id,
     });
 
     if (prevPath) {

changelogs/unreleased/50584-fix-ide-commit-twice.yml

+---
+title: Fix Web IDE unable to commit to same file twice
+merge_request: 21372
+author:
+type: fixed

spec/javascripts/ide/stores/modules/commit/actions_spec.js

@@ -184,7 +184,7 @@ describe('IDE commit module actions', () => {
           branch,
         })
         .then(() => {
-          expect(f.lastCommit.message).toBe(data.message);
+          expect(f.lastCommitSha).toBe(data.id);
         })
         .then(done)
         .catch(done.fail);
@@ -266,10 +266,7 @@ describe('IDE commit module actions', () => {
     });
 
     describe('success', () => {
-      beforeEach(() => {
-        spyOn(service, 'commit').and.returnValue(
-          Promise.resolve({
-            data: {
+      const COMMIT_RESPONSE = {
         id: '123456',
         short_id: '123',
         message: 'test message',
@@ -278,7 +275,12 @@ describe('IDE commit module actions', () => {
           additions: '1',
           deletions: '2',
         },
-            },
+      };
+
+      beforeEach(() => {
+        spyOn(service, 'commit').and.returnValue(
+          Promise.resolve({
+            data: COMMIT_RESPONSE,
           }),
         );
       });
@@ -352,8 +354,8 @@ describe('IDE commit module actions', () => {
         store
           .dispatch('commit/commitChanges')
           .then(() => {
-            expect(store.state.entries[store.state.openFiles[0].path].lastCommit.message).toBe(
-              'test message',
+            expect(store.state.entries[store.state.openFiles[0].path].lastCommitSha).toBe(
+              COMMIT_RESPONSE.id,
             );
 
             done();