Patch Set 3:

The idea is really cool. Some remarks, though:

1. could this be handled in the same way as when the user selects/deselects the "Add Signed-Off-By" checkbox, i.e. the commit message is updated immediately? This would be much more user-friendly in my opinion. If the correct change id is impossible to caculate, maybe adding a line like

"Change-Id: <will be calculated during commit>" to the message would give the user some feeling what they are doing.

2. When "amending" a commit with a Change-Id and removing the Change-Id line, the "Compute Change-Id" checkbox correctly becomes acive. However, even if it is still checked, when "committing" the amended change, the Change-Id is not re-calculated.

3. When going for the suggestion in 1., perhaps the checkbox should always be active, and when it is unchecked, the Commit-Id line should be removed from the message.