Mypy report does not get generated when cache is fresh

[qria]

Mypy report does not get generated when cache is fresh (i.e. not stale).

Say we have a python file a.py:

a.py

def foo():
	pass

Without .mypy_cache folder xml report generated by mypy a.py --xml-report . is as follows:

index.xml

<?xml-stylesheet type="text/xsl" href="mypy-html.xslt"?><mypy-report-index name="index"><file module="a" name="a.py" total="2" any="1" empty="1" imprecise="0" precise="0" unanalyzed="0"/></mypy-report-index>

However running mypy a.py --xml-report . again produces this:

index.xml

<?xml-stylesheet type="text/xsl" href="mypy-html.xslt"?><mypy-report-index name="index"/>

Removing .mypy_cache and running it again properly generates the report.

Versions:

python version: 3.6.5
mypy version: mypy-0.610+dev.76d60b018c93f6879a01a30f89bf0586c610bc06
lxml version: lxml-4.2.1

[mchlnix]

Same thing happens to me with the html report.

[gvanrossum]

Unfortunately this is a known problem with the reports. Use --no-incremental for reports.

[mchlnix]

If this isn't a duplicate, a bug label might aid visibility.

[gvanrossum]

Technically it's already mentioned here: #1123 (comment)

But I'm happy to keep this open as a separate issue. It's unlikely to be fixed in any way other than forcing incremental mode off when generating the reports though...