firstmergecache: ignore permission and OS errors when writing This cache is related to the obshashrange one and we update it lazily by default. This can be an issue when pulling locally from a read only repository that was not configured for a more aggressive cache warming. The raised permission error was uncaught and could crash the whole process. Errors during cache update should not block Mercurial operations.

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