FIX: revoke removed attachment blob URLs in the conversation editor

frontend/src/components/Chat/ConversationEditor.test.tsx

@@ -289,3 +289,18 @@ describe('ConversationEditor', () => {
     expect(onSaved).not.toHaveBeenCalled()
   })
 })
+
+it('revokes the blob URL when an attachment is removed from the editor', async () => {
+  const user = userEvent.setup()
+  const mockObjectUrl = 'blob:http://localhost/attach-1'
+  global.URL.createObjectURL = jest.fn().mockReturnValue(mockObjectUrl)
+  global.URL.revokeObjectURL = jest.fn()
+  setupEditor()
+
+  const first = screen.getByRole('region', { name: 'Message 1' })
+  await user.upload(within(first).getAllByTestId('file-input')[0], new File(['x'], 'photo.png', { type: 'image/png' }))
+
+  await user.click(await screen.findByRole('button', { name: 'Remove photo.png' }))
+
+  expect(global.URL.revokeObjectURL).toHaveBeenCalledWith(mockObjectUrl)
+})

frontend/src/components/Chat/ConversationEditor.tsx

@@ -101,8 +101,13 @@ function DraftPieceEditor({ piece, disabled, onChange, onAttachments, onConverte
       })
   }, [media, onChange, piece.draftId])
   const changeAttachments = useCallback((attachments: MessageAttachment[]): void => {
+    if (media) {
+      const nextUrls = new Set(attachments.map((attachment: MessageAttachment) => attachment.url))
+      const current = draftAttachment(piece)
+      if (!nextUrls.has(current.url) && current.url.startsWith('blob:')) URL.revokeObjectURL(current.url)
+    }
     onAttachments(piece.draftId, attachments)
-  }, [onAttachments, piece.draftId])
+  }, [media, piece, onAttachments])
   const clearConversion = (): void => onChange(piece.draftId, (current: ConversationDraftPiece) => ({
     ...current, converted_value: undefined, converted_value_data_type: undefined, applied_converter_ids: [],
   }))