A change ID is stable over time as you tweak the message of the change or the files edited by the change. Each of these changes become a new immutable git commit under the hood.
The fact that change ID is stable is very convenient for humans - means you have something explicit to hold on to as everything else may change over time.
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What changes the change ID? What constitutes a change? Is a change made up of many commits, or the other way around?
A change ID is stable over time as you tweak the message of the change or the files edited by the change. Each of these changes become a new immutable git commit under the hood.
The fact that change ID is stable is very convenient for humans - means you have something explicit to hold on to as everything else may change over time.