logging: add trace statements when changes are ignored (#36259)

* logging: add trace statements when changes are ignored

* copywrite headers

internal/backend/local/backend_apply.go

@@ -16,7 +16,6 @@ import (
 	"github.com/hashicorp/terraform/internal/addrs"
 	"github.com/hashicorp/terraform/internal/backend/backendrun"
 	"github.com/hashicorp/terraform/internal/command/views"
-	viewsjson "github.com/hashicorp/terraform/internal/command/views/json"
 	"github.com/hashicorp/terraform/internal/configs"
 	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/internal/plans"
@@ -348,7 +347,7 @@ func (b *Local) opApply(
 						diags = diags.Append(&hcl.Diagnostic{
 							Severity: hcl.DiagError,
 							Summary:  "Can't change variable when applying a saved plan",
-							Detail:   fmt.Sprintf("The variable %s cannot be set using the -var and -var-file options when applying a saved plan file, because a saved plan includes the variable values that were set when it was created. The saved plan specifies %s as the value whereas during apply the value %s was %s. To declare an ephemeral variable which is not saved in the plan file, use ephemeral = true.", varName, viewsjson.CompactValueStr(parsedVar.Value), viewsjson.CompactValueStr(plannedVar), parsedVar.SourceType.DiagnosticLabel()),
+							Detail:   fmt.Sprintf("The variable %s cannot be set using the -var and -var-file options when applying a saved plan file, because a saved plan includes the variable values that were set when it was created. The saved plan specifies %s as the value whereas during apply the value %s was %s. To declare an ephemeral variable which is not saved in the plan file, use ephemeral = true.", varName, tfdiags.CompactValueStr(parsedVar.Value), tfdiags.CompactValueStr(plannedVar), parsedVar.SourceType.DiagnosticLabel()),
 							Subject:  rng,
 						})
 					}

internal/command/views/json/diagnostic.go

@@ -5,7 +5,6 @@ package json
 
 import (
 	"bufio"
-	"bytes"
 	"fmt"
 	"sort"
 	"strings"
@@ -14,9 +13,10 @@ import (
 	"github.com/hashicorp/hcl/v2/hcled"
 	"github.com/hashicorp/hcl/v2/hclparse"
 	"github.com/hashicorp/hcl/v2/hclsyntax"
+	"github.com/zclconf/go-cty/cty"
+
 	"github.com/hashicorp/terraform/internal/lang/marks"
 	"github.com/hashicorp/terraform/internal/tfdiags"
-	"github.com/zclconf/go-cty/cty"
 )
 
 // These severities map to the tfdiags.Severity values, plus an explicit
@@ -289,7 +289,7 @@ func NewDiagnostic(diag tfdiags.Diagnostic, sources map[string][]byte) *Diagnost
 							continue
 						}
 
-						traversalStr := traversalStr(traversal)
+						traversalStr := tfdiags.TraversalStr(traversal)
 						if _, exists := seen[traversalStr]; exists {
 							continue Traversals // don't show duplicates when the same variable is referenced multiple times
 						}
@@ -382,7 +382,7 @@ func NewDiagnostic(diag tfdiags.Diagnostic, sources map[string][]byte) *Diagnost
 								value.Statement = "will be known only after apply"
 							}
 						default:
-							value.Statement = fmt.Sprintf("is %s", compactValueStr(val))
+							value.Statement = fmt.Sprintf("is %s", tfdiags.CompactValueStr(val))
 						}
 						values = append(values, value)
 						seen[traversalStr] = struct{}{}
@@ -437,129 +437,3 @@ func parseRange(src []byte, rng hcl.Range) (*hcl.File, int) {
 
 	return file, offset
 }
-
-// CompactValueStr produces a compact, single-line summary of a given value
-// that is suitable for display in the UI.
-//
-// For primitives it returns a full representation, while for more complex
-// types it instead summarizes the type, size, etc to produce something
-// that is hopefully still somewhat useful but not as verbose as a rendering
-// of the entire data structure.
-func CompactValueStr(val cty.Value) string {
-	return compactValueStr(val)
-}
-
-func compactValueStr(val cty.Value) string {
-	// This is a specialized subset of value rendering tailored to producing
-	// helpful but concise messages in diagnostics. It is not comprehensive
-	// nor intended to be used for other purposes.
-
-	val, valMarks := val.Unmark()
-	for mark := range valMarks {
-		switch mark {
-		case marks.Sensitive:
-			// We check this in here just to make sure, but note that the caller
-			// of compactValueStr ought to have already checked this and skipped
-			// calling into compactValueStr anyway, so this shouldn't actually
-			// be reachable.
-			return "(sensitive value)"
-		case marks.Ephemeral:
-			// A non-sensitive ephemeral value is fine to show in the UI. Values
-			// that are both ephemeral and sensitive should have both markings
-			// and should therefore get caught by the marks.Sensitive case
-			// above.
-			continue
-		default:
-			// We don't know about any other marks, so we'll be conservative.
-			// This shouldn't actuallyr eachable since the caller should've
-			// checked this and skipped calling compactValueStr anyway.
-			return "value with unrecognized marks (this is a bug in Terraform)"
-		}
-	}
-
-	// WARNING: We've only checked that the value isn't sensitive _shallowly_
-	// here, and so we must never show any element values from complex types
-	// in here. However, it's fine to show map keys and attribute names because
-	// those are never sensitive in isolation: the entire value would be
-	// sensitive in that case.
-
-	ty := val.Type()
-	switch {
-	case val.IsNull():
-		return "null"
-	case !val.IsKnown():
-		// Should never happen here because we should filter before we get
-		// in here, but we'll do something reasonable rather than panic.
-		return "(not yet known)"
-	case ty == cty.Bool:
-		if val.True() {
-			return "true"
-		}
-		return "false"
-	case ty == cty.Number:
-		bf := val.AsBigFloat()
-		return bf.Text('g', 10)
-	case ty == cty.String:
-		// Go string syntax is not exactly the same as HCL native string syntax,
-		// but we'll accept the minor edge-cases where this is different here
-		// for now, just to get something reasonable here.
-		return fmt.Sprintf("%q", val.AsString())
-	case ty.IsCollectionType() || ty.IsTupleType():
-		l := val.LengthInt()
-		switch l {
-		case 0:
-			return "empty " + ty.FriendlyName()
-		case 1:
-			return ty.FriendlyName() + " with 1 element"
-		default:
-			return fmt.Sprintf("%s with %d elements", ty.FriendlyName(), l)
-		}
-	case ty.IsObjectType():
-		atys := ty.AttributeTypes()
-		l := len(atys)
-		switch l {
-		case 0:
-			return "object with no attributes"
-		case 1:
-			var name string
-			for k := range atys {
-				name = k
-			}
-			return fmt.Sprintf("object with 1 attribute %q", name)
-		default:
-			return fmt.Sprintf("object with %d attributes", l)
-		}
-	default:
-		return ty.FriendlyName()
-	}
-}
-
-// traversalStr produces a representation of an HCL traversal that is compact,
-// resembles HCL native syntax, and is suitable for display in the UI.
-func traversalStr(traversal hcl.Traversal) string {
-	// This is a specialized subset of traversal rendering tailored to
-	// producing helpful contextual messages in diagnostics. It is not
-	// comprehensive nor intended to be used for other purposes.
-
-	var buf bytes.Buffer
-	for _, step := range traversal {
-		switch tStep := step.(type) {
-		case hcl.TraverseRoot:
-			buf.WriteString(tStep.Name)
-		case hcl.TraverseAttr:
-			buf.WriteByte('.')
-			buf.WriteString(tStep.Name)
-		case hcl.TraverseIndex:
-			buf.WriteByte('[')
-			if keyTy := tStep.Key.Type(); keyTy.IsPrimitiveType() {
-				buf.WriteString(compactValueStr(tStep.Key))
-			} else {
-				// We'll just use a placeholder for more complex values,
-				// since otherwise our result could grow ridiculously long.
-				buf.WriteString("...")
-			}
-			buf.WriteByte(']')
-		}
-	}
-	return buf.String()
-}

internal/terraform/eval_context_builtin.go

@@ -407,7 +407,7 @@ func (ctx *BuiltinEvalContext) EvaluateReplaceTriggeredBy(expr hcl.Expression, r
 		return nil, false, diags
 	}
 
-	path := traversalToPath(ref.Remaining)
+	path, _ := traversalToPath(ref.Remaining)
 	attrBefore, _ := path.Apply(change.Before)
 	attrAfter, _ := path.Apply(change.After)
 

internal/terraform/node_resource_abstract_instance.go

@@ -1252,14 +1252,16 @@ func (n *NodeAbstractResource) processIgnoreChanges(prior, config cty.Value, sch
 		return config, nil
 	}
 
-	ignoreChanges := traversalsToPaths(n.Config.Managed.IgnoreChanges)
+	ignoreChanges, keys := traversalsToPaths(n.Config.Managed.IgnoreChanges)
 	ignoreAll := n.Config.Managed.IgnoreAllChanges
 
 	if len(ignoreChanges) == 0 && !ignoreAll {
 		return config, nil
 	}
 
 	if ignoreAll {
+		log.Printf("[TRACE] processIgnoreChanges: Ignoring all changes for %s", n.Addr)
+
 		// Legacy providers need up to clean up their invalid plans and ensure
 		// no changes are passed though, but that also means making an invalid
 		// config with computed values. In that case we just don't supply a
@@ -1282,6 +1284,7 @@ func (n *NodeAbstractResource) processIgnoreChanges(prior, config cty.Value, sch
 
 		return ret, nil
 	}
+	log.Printf("[TRACE] processIgnoreChanges: Ignoring changes for %s at [%s]", n.Addr, strings.Join(keys, ", "))
 
 	if prior.IsNull() || config.IsNull() {
 		// Ignore changes doesn't apply when we're creating for the first time.
@@ -1296,36 +1299,49 @@ func (n *NodeAbstractResource) processIgnoreChanges(prior, config cty.Value, sch
 
 // Convert the hcl.Traversal values we get form the configuration to the
 // cty.Path values we need to operate on the cty.Values
-func traversalsToPaths(traversals []hcl.Traversal) []cty.Path {
+func traversalsToPaths(traversals []hcl.Traversal) ([]cty.Path, []string) {
 	paths := make([]cty.Path, len(traversals))
+	keys := make([]string, len(traversals))
 	for i, traversal := range traversals {
-		path := traversalToPath(traversal)
+		path, key := traversalToPath(traversal)
 		paths[i] = path
+		keys[i] = key
 	}
-	return paths
+	return paths, keys
 }
 
-func traversalToPath(traversal hcl.Traversal) cty.Path {
+func traversalToPath(traversal hcl.Traversal) (cty.Path, string) {
 	path := make(cty.Path, len(traversal))
+	var key strings.Builder
 	for si, step := range traversal {
 		switch ts := step.(type) {
 		case hcl.TraverseRoot:
 			path[si] = cty.GetAttrStep{
 				Name: ts.Name,
 			}
+			key.WriteString(ts.Name)
 		case hcl.TraverseAttr:
 			path[si] = cty.GetAttrStep{
 				Name: ts.Name,
 			}
+			key.WriteString(".")
+			key.WriteString(ts.Name)
 		case hcl.TraverseIndex:
 			path[si] = cty.IndexStep{
 				Key: ts.Key,
 			}
+			if ts.Key.Type().IsPrimitiveType() {
+				key.WriteString("[")
+				key.WriteString(tfdiags.CompactValueStr(ts.Key))
+				key.WriteString("]")
+			} else {
+				key.WriteString("[...]")
+			}
 		default:
 			panic(fmt.Sprintf("unsupported traversal step %#v", step))
 		}
 	}
-	return path
+	return path, key.String()
 }
 
 func processIgnoreChangesIndividual(prior, config cty.Value, ignoreChangesPath []cty.Path) (cty.Value, tfdiags.Diagnostics) {

internal/terraform/node_resource_validate.go

@@ -366,7 +366,7 @@ func (n *NodeValidatableResource) validateResource(ctx EvalContext) tfdiags.Diag
 				// use that to check whether the Attribute is Computed and
 				// non-Optional.
 				if !diags.HasErrors() {
-					path := traversalToPath(traversal)
+					path, _ := traversalToPath(traversal)
 
 					attrSchema := schema.AttributeByPath(path)
 

internal/terraform/reduce_plan_test.go

@@ -433,7 +433,8 @@ func TestProcessIgnoreChangesIndividual(t *testing.T) {
 				ignore[i] = trav
 			}
 
-			ret, diags := processIgnoreChangesIndividual(test.Old, test.New, traversalsToPaths(ignore))
+			paths, _ := traversalsToPaths(ignore)
+			ret, diags := processIgnoreChangesIndividual(test.Old, test.New, paths)
 			if diags.HasErrors() {
 				t.Fatal(diags.Err())
 			}