Route data maps ignore meta-merge options in 0.7.0, breaking compatibility

[Stefan van der Meer]

In 0.6.0, nested map data is merged in a way that matches meta-merge, supporting ^:replace:

user> (meta-merge {:roles {:foo false :bar true}} {:roles ^:replace {:foo true}})
{:roles {:foo true}}

user> (r/routes (r/router
                 ["/context" {:roles {:foo false :bar true}}
                  ["/leaf" {:roles ^:replace {:foo true}}]]))
[["/context/leaf" {:roles {:foo true}}]]

In 0.7.0, this is no longer the case, ^:replace is not respected:

user> (r/routes (r/router
                 ["/context" {:roles {:foo false :bar true}}
                  ["/leaf" {:roles ^:replace {:foo true}}]]))
[["/context/leaf" {:roles {:foo true, :bar true}}]]

This is not documented in the changelog so I assume it's not intentional.

[Stefan van der Meer]

I have found a workaround of sorts by fully disabling :update-paths functionality:

user> (r/routes (r/router
                 ["/context" {:roles {:foo false :bar true}}
                  ["/leaf" {:roles ^:replace {:foo true}}]]
                 {:update-paths nil}))
[["/context/leaf" {:roles {:foo true}}]]

As a result presumably losing out on the schema merging fixes. (edit: Actually seems to cause more fundamental errors with plumatic schemas, so it's not a practical workaround.)

The root cause of the issue is that update-paths strips metadata from nested maps (strictly: rebuilds the maps from scratch without retaining metadata), preventing meta-merge from ever seeing it, so it's not surprising that meta-merge directives on maps have no effect.

[Tommi Reiman]

You are right, this is a regression.

[Tommi Reiman]

fixed and released in 0.7.1.