dag: detect self references, use multierror
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parent
de3d9fb9d9
commit
5b0004ffc7
22
dag/dag.go
22
dag/dag.go
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@ -4,6 +4,8 @@ import (
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"fmt"
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"strings"
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"sync"
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"github.com/hashicorp/go-multierror"
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)
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// AcyclicGraph is a specialization of Graph that cannot have cycles. With
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@ -45,6 +47,8 @@ func (g *AcyclicGraph) Validate() error {
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return err
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}
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// Look for cycles of more than 1 component
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var err error
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var cycles [][]Vertex
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for _, cycle := range StronglyConnected(&g.Graph) {
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if len(cycle) > 1 {
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@ -52,20 +56,26 @@ func (g *AcyclicGraph) Validate() error {
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}
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}
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if len(cycles) > 0 {
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cyclesStr := make([]string, len(cycles))
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for i, cycle := range cycles {
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for _, cycle := range cycles {
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cycleStr := make([]string, len(cycle))
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for j, vertex := range cycle {
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cycleStr[j] = VertexName(vertex)
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}
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cyclesStr[i] = strings.Join(cycleStr, ", ")
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err = multierror.Append(err, fmt.Errorf(
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"Cycle: %s", strings.Join(cycleStr, ", ")))
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}
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return fmt.Errorf("cycles: %s", cyclesStr)
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}
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return nil
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// Look for cycles to self
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for _, e := range g.Edges() {
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if e.Source() == e.Target() {
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err = multierror.Append(err, fmt.Errorf(
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"Self reference: %s", VertexName(e.Source())))
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}
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}
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return err
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}
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// Walk walks the graph, calling your callback as each node is visited.
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@ -75,6 +75,17 @@ func TestAcyclicGraphValidate_cycle(t *testing.T) {
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}
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}
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func TestAcyclicGraphValidate_cycleSelf(t *testing.T) {
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var g AcyclicGraph
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g.Add(1)
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g.Add(2)
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g.Connect(BasicEdge(1, 1))
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if err := g.Validate(); err == nil {
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t.Fatal("should error")
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}
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}
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func TestAcyclicGraphWalk(t *testing.T) {
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var g AcyclicGraph
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g.Add(1)
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@ -39,7 +39,7 @@ func (g *Graph) Vertices() []Vertex {
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// Edges returns the list of all the edges in the graph.
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func (g *Graph) Edges() []Edge {
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list := g.vertices.List()
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list := g.edges.List()
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result := make([]Edge, len(list))
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for i, v := range list {
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result[i] = v.(Edge)
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