Have a form view with an x2many field, and a context on that field,
depending on other fields of the view. For instance:
```xml
<form>
<field name="a"/>
<field name="b_ids" context="{'key1': a, 'key2': 4}"/>
</form>
```
As we read records in a single rpc (unity read), we need to be able
to (at least partially) evaluate the context set on b_ids to build
the field specification for the web_read call. The problem is that
the evaluation context is incomplete when we want to evalute it, as
we don't know the value of `a`.
Before this commit, we evaluated that context by adding "sentinel"
values in the evaluation context (a sentinel being a Symbol), and
we removed all keys whose values had been evaluated to the sentinel
afterwards. This worked for the example above (we were able to
generate the context `{ key2: 4 }`).
However, this wasn't flawless. For instance, with
```xml
<field name="b_ids" context="{'key1': a + b}"/>
```
our sentinel strategy didn't work, because you can't perform such
operations on a Symbol.
This commit comes with another strategy, which is actually easier,
and which handles the above case. We now parse the context, and
evaluate each value individually (if it needs to be evaluated). If
the evaluation crashes, we swallow the error and do not add that
particular key to the evaluated context.
Part of task~3179751
closesodoo/odoo#129925
Signed-off-by: Géry Debongnie <ged@odoo.com>
Aaron Bohy
7dc6958334