First, rewinding head to replay your work on top of it...
Applying: content_add: Write to the objstorage before the DB or Kafka

commit 1180902ab75f4b92fce4e68e4e00c111d5250156
Author: Valentin Lorentz <vlorentz@softwareheritage.org>
Date:   Mon Mar 15 12:50:41 2021 +0100

    content_add: Write to the objstorage before the DB or Kafka
    
    Must add to the objstorage before the DB and journal. Otherwise:
    1. in case of a crash the DB may "believe" we have the content, but
       we didn't have time to write to the objstorage before the crash
    2. the objstorage mirroring, which reads from the journal, may attempt to
       read from the objstorage before we finished writing it
    
    This is already done in the postgresql backend unintentionally since
    209de5dbaa127dacd114fbbd084f22632982eb77.
    
    This commit makes the cassandra backend behave that way too, and adds a
    test.

First, rewinding head to replay your work on top of it...
Applying: content_add: Write to the objstorage before the DB or Kafka

commit 53df7470a8be339ec04fc9eea5ca8cbff68a61a7
Author: Valentin Lorentz <vlorentz@softwareheritage.org>
Date:   Mon Mar 15 12:50:41 2021 +0100

    content_add: Write to the objstorage before the DB or Kafka
    
    Must add to the objstorage before the DB and journal. Otherwise:
    1. in case of a crash the DB may "believe" we have the content, but
       we didn't have time to write to the objstorage before the crash
    2. the objstorage mirroring, which reads from the journal, may attempt to
       read from the objstorage before we finished writing it
    
    This is already done in the postgresql backend unintentionally since
    209de5dbaa127dacd114fbbd084f22632982eb77.
    
    This commit documents it, makes the cassandra backend behave that way too,
    and adds a test.