Explaining prerequisite checks for build results and what to do about them.

mps/procedure/pull-request-merge.rst

@@ -51,33 +51,54 @@ reference to that project.  RB 2023-01-07]
 
 #. Has there been a code review?
 
-#. Does the branch build and pass tests on all target platforms?
-   [This may have been validated by Travis CI if the branch is in the
-   Ravenbrook MPS repo on GitHub.  If not, we could add a step to push
-   it there for this purpose.  RB 2023-01-08]
+#. Does the branch build and pass tests on all `target platforms
+   <../readme.txt>`_?
 
-#. Does the branch merge cleanly into the masters?  If not, consider a
-   catch-up merge from the masters.  [This may be validated by GitHub
-   and/or Travis CI.  Insert details here.  RB 2023-01-07] [This is
-   duplicated by step 3 of the procedure.  RB 2023-01-07]
+   If the branch is in the Ravenbrook MPS repo on GitHub then Travis
+   CI should have run builds.  Look for a successful build in the
+   `Travis CI build history for the repo
+   <https://app.travis-ci.com/github/Ravenbrook/mps/builds>`_.  If
+   there is a failed build you should not execute this procedure, but
+   talk to the contributor about fixing the branch.
+
+   If the branch is in the Ravenbrook MPS repo on GitHub and Travis
+   builds are missing, inform sysadmins that Travis CI isn't
+   functioning.
+
+   If you have no build and test results, you can still execute this
+   procedure, with caution.
 
 #. Does the branch merge cleanly in to master and pass tests on all
    target platforms?
 
-   Travis CI should have run builds.  To check, either:
+   Travis CI should have run builds of the pull request (i.e. `of a
+   merge with master
+   <https://docs.travis-ci.com/user/pull-requests/#how-pull-requests-are-built>`_).
+   To check, either:
 
-   - Look for "All checks have passed" in the pull request on GitHub,
-     expand "Show all checks", and look for build success messages
+   - Look for "All checks have passed" in the pull request on GitHub.
+     Expand "Show all checks", and look for build success messages
      from Travis CI.
 
    - Look for a successful build in the `Travis CI build history for
      the repo
      <https://app.travis-ci.com/github/Ravenbrook/mps/builds>`_.
 
-  [Failure here is not necessarily a failure of this procedure, since
-  this procedure includes conflict resolution and testing the result.
-  Insisiting on this step would move that work upstream, which might
-  be efficient.  RB 2023-01-08]
+   Success by Travis CI is a strong indication that this procecure
+   will be quick and successful.
+
+   If Travis builds failed, you can still execute this procedure if
+   you believe that the failure is due to merge conflicts that you are
+   willing to resolve.
+
+   If Travis builds are missing, inform sysadmins that Travis CI isn't
+   functioning.
+
+   If you have no build and test results for the merge, then you can
+   still execute this procedure if:
+   # you believe there are only merge conflicts,
+   # you're willing to try to resolve those conflicts, and
+   # you're prepared to test on all target platforms.
 
 [Checklist items for Customer-specific branches from branch-merge.rst
 omitted for now.  RB 2023-01-07]