Behaviour of `assertion count` in different ModelSim versions - tcl

Question

I have written test-automation script in TCL for ModelSim which in its essense runs
vcom -work work -2002 -explicit -source -cover sbce3 something.vhd
# ...
vsim -assertcover -t 10ps -cover -displaymsgmode both -msgmode both "work.something" -quiet
once the simulation is over, I verify that all assertions passed with
set assertion_count [ assertion count -fails -r / ]
if {$assertion_count} {
# failed...
} else {
# success
}
this worked fine for some older ModelSim version (specifically PE 6.5b), but after switching to PE 10.4, assertion_count is always 0, thus my tests always "pass"!
Now the ModelSim PE Command Reference Manual (modelsim_pe_ref.pdf is behind a Mentor login-wall unfortunately), does not even mention the assertion ... command, the HTML manual (e.g. here) does mention it though.
Has something in ModelSim changed recently that breaks above pattern, do I use it wrongly (e.g. with missing parameters to vsim) or is there a better alternative?
I could use coverage report or coverage report -assert -detail for instance, but then I would need to parse the output
# NEVER FAILED: 97.0% ASSERTIONS: 105

Answer 1

I believe that Modelsim has change the default value of the log parameter of the assertions on the new versions.
In the previous versions, it seems that the default configuration of the assertions was with the log option enabled, but in the 10.4 all assertions are not logged when testbench is loaded, and when an assertion is triggered it is reported but it is not registered at the assertions panel (View – Coverage -- Assertions)
I fix this error invoking the logging function of the assertions:
assertion fail -log on -recursive /
It seems that invoking this command at the start of the sequence is enough to enable the logging process and it fix the problems with the assertions count command.

Answer 2

Official reply from ModelSim Support:
The "assertion count" command is not expected to work on Modelsim PE,
as it is not supposed to have assertion coverage metrics enabled.
Generate and parse a coverage report instead.