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ubuntu2204

CoCalc does collaborative text editing using the algorithm described here: https://blog.cocalc.com/2018/10/11/collaborative-editing.html

These are the patches that are produced when doing "The Color of Pomegranates" test in either order. In both cases the resulting document is empty after doing the edits. E.g., applying the patch [[[[0,"The Colo"],[1,"u"],[0,"r of Pom"]] using diffmatchpatch to the empty string results in an empty document, since the patch does not find the relevant context "The Colo". In general, what happens depends on a parameter to diffmatchpatch.

Of course, just try this for yourself in CoCalc by editing the same txt (or markdown) file in two browser tabs with the internet disabled, then reconnecting.

smc=# select * from patches where string_id='638484bac4fd1e7b0eeeface3bc99be6c6fe5106' order by time desc limit 15;
                string_id                 |          time           | user_id |                                            patch                                             | snapshot | sent |          prev           | format
------------------------------------------+-------------------------+---------+----------------------------------------------------------------------------------------------+----------+------+-------------------------+--------
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:31:45.523 |       1 | [[[[0,"The Colo"],[1,"u"],[0,"r of Pom"]],0,0,16,17]]                                        |          |      | 2024-12-06 21:30:31.666 |
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:31:42.259 |       1 | [[[[-1,"The Color of Pomegranates"]],0,0,25,0]]                                              |          |      | 2024-12-06 21:30:34.465 |
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:31:30.604 |       1 | [[[[1,"The Color of Pomegranates"]],0,0,0,25]]                                               |          |      |                         |
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:30:34.465 |       1 | [[[[-1,"The Color of Pomegranates"]],0,0,25,0]]                                              |          |      | 2024-12-06 21:29:02.125 |
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:30:31.666 |       1 | [[[[0,"The Colo"],[1,"u"],[0,"r of Pom"]],0,0,16,17]]                                        |          |      | 2024-12-06 21:30:10.633 |
 638484bac4fd1e7b0eeeface3bc99be6c6fe5106 | 2024-12-06 21:30:10.633 |       1 | [[[[1,"The Color of Pomegranates"]],0,0,0,25]]