cl-digraph.asd @ 884333cfb6fb v1.3.2

Detect *all* cycles during topological sort

Previously the cycle detection was limited to detecting when we hit
a currently-being-visited node during a traversal.  So something like this would
be correctly found:

    A --> B --> C
          ^     |
          |     |
          +-----+

We start at the root (A), go to B, then to C, then to B, and detect that we're
still working on B and signal the error.

But this doesn't find all cycles, because we *start* at the root nodes, and if
a cycle doesn't have any outcropping branches we'll never reach it at all.  For
example:

    A --> B
    ^     |
    |     |
    +-----+

This graph has no roots, so we incorrectly ignore the cycle.

This patch fixes the problem by keeping a count of visited nodes and and making
sure it matches the digraph's size at the end.

Fixes https://github.com/sjl/cl-digraph/issues/4

(asdf:defsystem :cl-digraph
  :description "Simple directed graphs for Common Lisp."
  :author "Steve Losh <steve@stevelosh.com>"
  :homepage "http://docs.stevelosh.com/cl-digraph/"

  :license "MIT/X11"
  :version "1.3.2"

  :depends-on ()

  :in-order-to ((asdf:test-op (asdf:test-op :cl-digraph.test)))

  :serial t
  :components ((:module "vendor" :serial t
                :components ((:file "quickutils-package")
                             (:file "quickutils")))
               (:file "package")
               (:module "src" :serial t
                :components ((:file "directed-graph")))))