instrument cwvreg, so we may know what's being loaded by asking the registry store

set proper PACKAGE information for yams 0.39 Yams 0.39 adds an unobstrusive API to get the package, or cube, defining a part of the schema (entity type, relation type/def). As CubicWeb overrides part of the schema reading process, we have to handle this information on our side so it will be properly set.

[yams] follow yams 0.39 api change introduced by ad95fd2c46de (package attribute on etype/rtype/rdef)

Make the GROUP_CONCAT aggregate function not repeat values (closes #3223975) Work on sets instead of arrays, so if the same value appears twice it's not repeated in the concatenated output. This patch handles the postgresql and sqlite backends, mysql is left alone at this point (seems doable, but I don't have time or motivation to fix and test it).

[mail] allow to specify SMTP's MAIL FROM address to config.sendmails(). Closes #3373620 Also modify testlib.Email so we don't loose this information and may test it.

[mail] format_mail copy/paste fix: we want to test sender-name, not sender-addr

symmetric relations: replace bogus rql2sql translation by a hook The hook ensures X r Y => Y r X iff r is symmetric. The rql-no-hook data importer receives a small amendment but note that: * there exist no test for it * its actual semantics are undefined Hence we cannot prove this hunk breaks nothing, because we cannot prove anything. Closes #3259713.

[migration] fix handling of default value for boolean attributes We can't assert that the old value is 'True' or 'False', because False used to be stored as an empty string in pre-3.18 versions.

[entity/url publishing] fetch_rqlst should use 'is_instance_of' instead of 'is' We usually want to get any subclasses as well (think Training subclass of Workcase). Closes #3210365.

[rewriter] fix latent bug: arbitrary etype may be substituted when using is_instance_of type restriction Note: the test is not deterministic because the bug depends on the iteration order on a set.