compat: add a fixed version of mergecopies for hg<=4.3
In hg<=4.3, copies._fullcopytracing() does not exist and we have to wrap
copies.mergecopies() to fix the AssertionError coming from core.
import hghave
@hghave.check("docgraph-ext", "Extension to generate graph from repository")
def docgraph():
try:
import hgext.docgraph
hgext.docgraph.cmdtable # trigger import
except ImportError:
try:
import hgext3rd.docgraph
hgext3rd.docgraph.cmdtable # trigger import
except ImportError:
return False
return True