mirror of
https://github.com/opentofu/opentofu.git
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218 lines
7.3 KiB
Go
218 lines
7.3 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: MPL-2.0
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package tofu
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import (
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"fmt"
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"log"
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"github.com/opentofu/opentofu/internal/addrs"
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"github.com/opentofu/opentofu/internal/configs"
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"github.com/opentofu/opentofu/internal/dag"
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"github.com/opentofu/opentofu/internal/plans"
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"github.com/opentofu/opentofu/internal/states"
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"github.com/opentofu/opentofu/internal/tfdiags"
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)
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// DiffTransformer is a GraphTransformer that adds graph nodes representing
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// each of the resource changes described in the given Changes object.
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type DiffTransformer struct {
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Concrete ConcreteResourceInstanceNodeFunc
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State *states.State
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Changes *plans.Changes
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Config *configs.Config
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}
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// return true if the given resource instance has either Preconditions or
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// Postconditions defined in the configuration.
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func (t *DiffTransformer) hasConfigConditions(addr addrs.AbsResourceInstance) bool {
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// unit tests may have no config
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if t.Config == nil {
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return false
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}
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cfg := t.Config.DescendentForInstance(addr.Module)
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if cfg == nil {
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return false
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}
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res := cfg.Module.ResourceByAddr(addr.ConfigResource().Resource)
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if res == nil {
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return false
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}
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return len(res.Preconditions) > 0 || len(res.Postconditions) > 0
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}
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func (t *DiffTransformer) Transform(g *Graph) error {
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if t.Changes == nil || len(t.Changes.Resources) == 0 {
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// Nothing to do!
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return nil
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}
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// Go through all the modules in the diff.
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log.Printf("[TRACE] DiffTransformer starting")
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var diags tfdiags.Diagnostics
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state := t.State
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changes := t.Changes
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// DiffTransformer creates resource _instance_ nodes. If there are any
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// whole-resource nodes already in the graph, we must ensure that they
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// get evaluated before any of the corresponding instances by creating
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// dependency edges, so we'll do some prep work here to ensure we'll only
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// create connections to nodes that existed before we started here.
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resourceNodes := map[string][]GraphNodeConfigResource{}
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for _, node := range g.Vertices() {
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rn, ok := node.(GraphNodeConfigResource)
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if !ok {
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continue
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}
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// We ignore any instances that _also_ implement
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// GraphNodeResourceInstance, since in the unlikely event that they
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// do exist we'd probably end up creating cycles by connecting them.
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if _, ok := node.(GraphNodeResourceInstance); ok {
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continue
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}
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addr := rn.ResourceAddr().String()
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resourceNodes[addr] = append(resourceNodes[addr], rn)
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}
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for _, rc := range changes.Resources {
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addr := rc.Addr
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dk := rc.DeposedKey
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log.Printf("[TRACE] DiffTransformer: found %s change for %s %s", rc.Action, addr, dk)
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// Depending on the action we'll need some different combinations of
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// nodes, because destroying uses a special node type separate from
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// other actions.
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var update, delete, createBeforeDestroy bool
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switch rc.Action {
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case plans.NoOp:
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// For a no-op change we don't take any action but we still
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// run any condition checks associated with the object, to
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// make sure that they still hold when considering the
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// results of other changes.
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update = t.hasConfigConditions(addr)
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case plans.Delete:
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delete = true
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case plans.DeleteThenCreate, plans.CreateThenDelete:
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update = true
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delete = true
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createBeforeDestroy = (rc.Action == plans.CreateThenDelete)
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default:
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update = true
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}
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// A deposed instance may only have a change of Delete or NoOp. A NoOp
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// can happen if the provider shows it no longer exists during the most
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// recent ReadResource operation.
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if dk != states.NotDeposed && !(rc.Action == plans.Delete || rc.Action == plans.NoOp) {
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diags = diags.Append(tfdiags.Sourceless(
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tfdiags.Error,
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"Invalid planned change for deposed object",
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fmt.Sprintf("The plan contains a non-delete change for %s deposed object %s. The only valid action for a deposed object is to destroy it, so this is a bug in OpenTofu.", addr, dk),
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))
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continue
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}
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// If we're going to do a create_before_destroy Replace operation then
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// we need to allocate a DeposedKey to use to retain the
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// not-yet-destroyed prior object, so that the delete node can destroy
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// _that_ rather than the newly-created node, which will be current
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// by the time the delete node is visited.
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if update && delete && createBeforeDestroy {
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// In this case, variable dk will be the _pre-assigned_ DeposedKey
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// that must be used if the update graph node deposes the current
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// instance, which will then align with the same key we pass
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// into the destroy node to ensure we destroy exactly the deposed
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// object we expect.
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if state != nil {
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ris := state.ResourceInstance(addr)
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if ris == nil {
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// Should never happen, since we don't plan to replace an
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// instance that doesn't exist yet.
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diags = diags.Append(tfdiags.Sourceless(
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tfdiags.Error,
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"Invalid planned change",
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fmt.Sprintf("The plan contains a replace change for %s, which doesn't exist yet. This is a bug in OpenTofu.", addr),
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))
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continue
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}
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// Allocating a deposed key separately from using it can be racy
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// in general, but we assume here that nothing except the apply
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// node we instantiate below will actually make new deposed objects
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// in practice, and so the set of already-used keys will not change
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// between now and then.
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dk = ris.FindUnusedDeposedKey()
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} else {
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// If we have no state at all yet then we can use _any_
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// DeposedKey.
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dk = states.NewDeposedKey()
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}
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}
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if update {
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// All actions except destroying the node type chosen by t.Concrete
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abstract := NewNodeAbstractResourceInstance(addr)
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var node dag.Vertex = abstract
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if f := t.Concrete; f != nil {
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node = f(abstract)
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}
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if createBeforeDestroy {
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// We'll attach our pre-allocated DeposedKey to the node if
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// it supports that. NodeApplyableResourceInstance is the
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// specific concrete node type we are looking for here really,
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// since that's the only node type that might depose objects.
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if dn, ok := node.(GraphNodeDeposer); ok {
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dn.SetPreallocatedDeposedKey(dk)
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}
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log.Printf("[TRACE] DiffTransformer: %s will be represented by %s, deposing prior object to %s", addr, dag.VertexName(node), dk)
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} else {
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log.Printf("[TRACE] DiffTransformer: %s will be represented by %s", addr, dag.VertexName(node))
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}
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g.Add(node)
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rsrcAddr := addr.ContainingResource().String()
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for _, rsrcNode := range resourceNodes[rsrcAddr] {
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g.Connect(dag.BasicEdge(node, rsrcNode))
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}
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}
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if delete {
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// Destroying always uses a destroy-specific node type, though
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// which one depends on whether we're destroying a current object
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// or a deposed object.
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var node GraphNodeResourceInstance
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abstract := NewNodeAbstractResourceInstance(addr)
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if dk == states.NotDeposed {
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node = &NodeDestroyResourceInstance{
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NodeAbstractResourceInstance: abstract,
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DeposedKey: dk,
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}
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} else {
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node = &NodeDestroyDeposedResourceInstanceObject{
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NodeAbstractResourceInstance: abstract,
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DeposedKey: dk,
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}
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}
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if dk == states.NotDeposed {
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log.Printf("[TRACE] DiffTransformer: %s will be represented for destruction by %s", addr, dag.VertexName(node))
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} else {
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log.Printf("[TRACE] DiffTransformer: %s deposed object %s will be represented for destruction by %s", addr, dk, dag.VertexName(node))
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}
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g.Add(node)
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}
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}
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log.Printf("[TRACE] DiffTransformer complete")
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return diags.Err()
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}
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