Steps and updates in the Continuous Integration process

1. Integration of b1 :

   • Reference: x0 is the default reference xp in dev_DV49_toT1 config file

   • Tests: b1 did not require to adapt the tests $\rightarrow$ we can test with branch dev_DV49_toT1 unchanged (and still equal to DV49)

   davai-new_xp dev_CY49_toT1 -v dev_DV49_toT1
   $~~~\hookrightarrow~~~$ xi1 == x1 == x0

2. Integration of b2 :

   • Reference: xi1 should normally be the reference xp, but since its results are bit-identical to x0 as opposed to x2, it is more relevant to compare to x2, to check that the merge of b1 and b2 still give the same results as b2

   • Tests: b2 did not require to adapt the tests $\rightarrow$ tests branch DV49_toT1 unchanged

   davai-new_xp dev_CY49_toT1 -v DV49_toT1
   $~~~$and set ref_xpid = x2
   $~~~\hookrightarrow~~~$ xi2 == x2

   • then ref_xpid should be set to xi2 in branch DV49_toT1

3. Integration of b3 :

   • Reference: b3 does not change the results, so reference experiment is as expected by default xi2

   • Tests: b3 requires tests adaptations (DV49_b3) $\rightarrow$ update dev_DV49_toT1 by merging DV49_b3 in

   davai-new_xp dev_CY49_toT1 -v DV49_toT1
   $~~~\hookrightarrow~~~$ xi3 == xi2

4. Integration of b4 : (where it becomes more or less tricky)

   • Reference: b4 changes the results, but the results of xi3 (current default reference for integration branch) are also changed from x0 (since b2) $\rightarrow$ the reference experiment becomes less obvious !
     The choice of the reference should be made depending on the width of impact on both sides:

     1. if there is more differences in the results between dev_CY49_toT1 and CY49 than between b4 and CY49:
        $\rightarrow$ xi3 should be taken as reference, and the differences finely compared to those shown in x4

     2. if there is more differences in the results between b4 and CY49 than between dev_CY49_toT1 and CY49:
        $\rightarrow$ x4 should be taken as reference, and the differences finely compared to those shown in xi3’, where xi3’ is a "witness" experiment comparing the integration branch after integration of b3 (commit <c3>) to CY49 (experiment x0):
        davai-new_xp <c3> -v dev_DV49_toT1
        $~~~$and set ref_xpid = x0
        $~~~\hookrightarrow~~~$ xi3’

     This is still OK if the tests affected by dev_CY49_toT1 (via b2) and the tests affected by b4 are not the same subset, or if at least if the affected fields are not the same. If they are (e.g. numerical differences that propagate prognostically through the model), the conclusion becomes much more difficult !!!
     In this case, we do not really have explicit recommendation; the integrators should double-check the result of the merge with the author of the contribution b4. Any idea welcome to sort it out.

   • Tests: b4 requires tests adaptations (DV49_b4) $\rightarrow$ update dev_DV49_toT1 by merging in DV49_b4 in

   davai-new_xp dev_CY49_toT1 -v dev_DV49_toT1
   $~~~$and set ref_xpid = xi3|xi4
   $~~~\hookrightarrow~~~$ xi4