Excluding multiple lines with exclude_lines

[asmeurer]

As far as I can tell, it isn't posible to exclude multiple lines with exclude_lines. If I am reading the code correctly, it uses the lines_matching function, which checks the regexes line-by-line

coveragepy/coverage/parser.py

Lines 99 to 115 in eb5d81a

	def lines_matching(self, *regexes):
	"""Find the lines matching one of a list of regexes.
	Returns a set of line numbers, the lines that contain a match for one
	of the regexes in `regexes`. The entire line needn't match, just a
	part of it.
	"""
	combined = join_regex(regexes)
	if env.PY2:
	combined = combined.decode("utf8")
	regex_c = re.compile(combined)
	matches = set()
	for i, ltext in enumerate(self.lines, start=1):
	if regex_c.search(ltext):
	matches.add(i)
	return matches

My use-case is I want to exclude lines like

except ValueError: 
    assume(False)

where assume is from hypothesis. Simply excluding assume(False) doesn't work because it doesn't exclude the except. I don't want to exclude other except ValueError blocks in the codebase. I know I can rewrite this as except ValueError: assume(False) on a single line, but I would prefer not to as I don't like code that does that.

What I would like to do is to write something like

[report]
exclude_lines = 
    except ValueError:\n *assume\(False\)

Or if that can't work

[report]
exclude_lines = 
    except ValueError:(?=\n *assume\(False\))

Neither of these work presently. As far as I can tell this can only be excluded by manually putting # pragma: no cover on each instance.

[nedbat]

This is an interesting idea. I'll have to think about how it could work....

[nedbat]

As of commit 1fe897d, you can do this with the multi-line exclusion regex you showed:

[report]
exclude_also =
    except ValueError:\n *assume\(False\)

[nedbat]

This is now released as part of coverage 7.6.0.