In other packages we've tried being pragmatic by making the main code
compensate for missing arguments in older tests, so that we don't always
need to update every test across the whole system every time we add a new
feature.
However, that compromise unfortunately tends to lead to non-test code
inadvertently relying on the compensations too, so this is an attempt at
a slightly different compromise where the main code will panic if called
incorrectly but there's an extra helper function for tests to fill in
reasonable "inert" defaults for the fields they leave unpopulated.
Signed-off-by: Martin Atkins <mart@degeneration.co.uk>
This also further highlighted that the marks-related codepaths in cty have
lots of room for performance improvement. In particular, we're spending
a lot of time in cty.Value.UnmarkDeep rebuilding values that actually
don't need to change and could likely get some benefit from rewriting
that to use the recently-added WrangleMarksDeep that is able to avoid
constructing new values for parts of the tree where no marks are changing.
Signed-off-by: Martin Atkins <mart@degeneration.co.uk>
