Use dynamic walking to validate unique resource keys (#1614)

## Changes
This PR:
1. Uses dynamic walking (via the `dyn.MapByPattern` func) to validate no
two resources have the same resource key. The allows us to remove this
validation at merge time.
2. Modifies `dyn.Mapping` to always return a sorted slice of pairs. This
makes traversal functions like `dyn.Walk` or `dyn.MapByPattern`
deterministic.

## Tests
Unit tests. Also manually.

bundle/config/mutator/mutator.go

@@ -5,6 +5,7 @@ import (
 	"github.com/databricks/cli/bundle/config"
 	"github.com/databricks/cli/bundle/config/loader"
 	pythonmutator "github.com/databricks/cli/bundle/config/mutator/python"
+	"github.com/databricks/cli/bundle/config/validate"
 	"github.com/databricks/cli/bundle/scripts"
 )
 
@@ -26,5 +27,9 @@ func DefaultMutators() []bundle.Mutator {
 		DefineDefaultTarget(),
 		LoadGitDetails(),
 		pythonmutator.PythonMutator(pythonmutator.PythonMutatorPhaseLoad),
+
+		// Note: This mutator must run before the target overrides are merged.
+		// See the mutator for more details.
+		validate.UniqueResourceKeys(),
 	}
 }

bundle/config/resources.go

@@ -20,126 +20,6 @@ type Resources struct {
 	QualityMonitors       map[string]*resources.QualityMonitor       `json:"quality_monitors,omitempty"`
 }
 
-type UniqueResourceIdTracker struct {
-	Type       map[string]string
-	ConfigPath map[string]string
-}
-
-// verifies merging is safe by checking no duplicate identifiers exist
-func (r *Resources) VerifySafeMerge(other *Resources) error {
-	rootTracker, err := r.VerifyUniqueResourceIdentifiers()
-	if err != nil {
-		return err
-	}
-	otherTracker, err := other.VerifyUniqueResourceIdentifiers()
-	if err != nil {
-		return err
-	}
-	for k := range otherTracker.Type {
-		if _, ok := rootTracker.Type[k]; ok {
-			return fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				rootTracker.Type[k],
-				rootTracker.ConfigPath[k],
-				otherTracker.Type[k],
-				otherTracker.ConfigPath[k],
-			)
-		}
-	}
-	return nil
-}
-
-// This function verifies there are no duplicate names used for the resource definations
-func (r *Resources) VerifyUniqueResourceIdentifiers() (*UniqueResourceIdTracker, error) {
-	tracker := &UniqueResourceIdTracker{
-		Type:       make(map[string]string),
-		ConfigPath: make(map[string]string),
-	}
-	for k := range r.Jobs {
-		tracker.Type[k] = "job"
-		tracker.ConfigPath[k] = r.Jobs[k].ConfigFilePath
-	}
-	for k := range r.Pipelines {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"pipeline",
-				r.Pipelines[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "pipeline"
-		tracker.ConfigPath[k] = r.Pipelines[k].ConfigFilePath
-	}
-	for k := range r.Models {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"mlflow_model",
-				r.Models[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "mlflow_model"
-		tracker.ConfigPath[k] = r.Models[k].ConfigFilePath
-	}
-	for k := range r.Experiments {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"mlflow_experiment",
-				r.Experiments[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "mlflow_experiment"
-		tracker.ConfigPath[k] = r.Experiments[k].ConfigFilePath
-	}
-	for k := range r.ModelServingEndpoints {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"model_serving_endpoint",
-				r.ModelServingEndpoints[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "model_serving_endpoint"
-		tracker.ConfigPath[k] = r.ModelServingEndpoints[k].ConfigFilePath
-	}
-	for k := range r.RegisteredModels {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"registered_model",
-				r.RegisteredModels[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "registered_model"
-		tracker.ConfigPath[k] = r.RegisteredModels[k].ConfigFilePath
-	}
-	for k := range r.QualityMonitors {
-		if _, ok := tracker.Type[k]; ok {
-			return tracker, fmt.Errorf("multiple resources named %s (%s at %s, %s at %s)",
-				k,
-				tracker.Type[k],
-				tracker.ConfigPath[k],
-				"quality_monitor",
-				r.QualityMonitors[k].ConfigFilePath,
-			)
-		}
-		tracker.Type[k] = "quality_monitor"
-		tracker.ConfigPath[k] = r.QualityMonitors[k].ConfigFilePath
-	}
-	return tracker, nil
-}
-
 type resource struct {
 	resource      ConfigResource
 	resource_type string

bundle/config/resources_test.go

@@ -5,129 +5,9 @@ import (
 	"reflect"
 	"testing"
 
-	"github.com/databricks/cli/bundle/config/paths"
-	"github.com/databricks/cli/bundle/config/resources"
 	"github.com/stretchr/testify/assert"
 )
 
-func TestVerifyUniqueResourceIdentifiers(t *testing.T) {
-	r := Resources{
-		Jobs: map[string]*resources.Job{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo.yml",
-				},
-			},
-		},
-		Models: map[string]*resources.MlflowModel{
-			"bar": {
-				Paths: paths.Paths{
-					ConfigFilePath: "bar.yml",
-				},
-			},
-		},
-		Experiments: map[string]*resources.MlflowExperiment{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo2.yml",
-				},
-			},
-		},
-	}
-	_, err := r.VerifyUniqueResourceIdentifiers()
-	assert.ErrorContains(t, err, "multiple resources named foo (job at foo.yml, mlflow_experiment at foo2.yml)")
-}
-
-func TestVerifySafeMerge(t *testing.T) {
-	r := Resources{
-		Jobs: map[string]*resources.Job{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo.yml",
-				},
-			},
-		},
-		Models: map[string]*resources.MlflowModel{
-			"bar": {
-				Paths: paths.Paths{
-					ConfigFilePath: "bar.yml",
-				},
-			},
-		},
-	}
-	other := Resources{
-		Pipelines: map[string]*resources.Pipeline{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo2.yml",
-				},
-			},
-		},
-	}
-	err := r.VerifySafeMerge(&other)
-	assert.ErrorContains(t, err, "multiple resources named foo (job at foo.yml, pipeline at foo2.yml)")
-}
-
-func TestVerifySafeMergeForSameResourceType(t *testing.T) {
-	r := Resources{
-		Jobs: map[string]*resources.Job{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo.yml",
-				},
-			},
-		},
-		Models: map[string]*resources.MlflowModel{
-			"bar": {
-				Paths: paths.Paths{
-					ConfigFilePath: "bar.yml",
-				},
-			},
-		},
-	}
-	other := Resources{
-		Jobs: map[string]*resources.Job{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo2.yml",
-				},
-			},
-		},
-	}
-	err := r.VerifySafeMerge(&other)
-	assert.ErrorContains(t, err, "multiple resources named foo (job at foo.yml, job at foo2.yml)")
-}
-
-func TestVerifySafeMergeForRegisteredModels(t *testing.T) {
-	r := Resources{
-		Jobs: map[string]*resources.Job{
-			"foo": {
-				Paths: paths.Paths{
-					ConfigFilePath: "foo.yml",
-				},
-			},
-		},
-		RegisteredModels: map[string]*resources.RegisteredModel{
-			"bar": {
-				Paths: paths.Paths{
-					ConfigFilePath: "bar.yml",
-				},
-			},
-		},
-	}
-	other := Resources{
-		RegisteredModels: map[string]*resources.RegisteredModel{
-			"bar": {
-				Paths: paths.Paths{
-					ConfigFilePath: "bar2.yml",
-				},
-			},
-		},
-	}
-	err := r.VerifySafeMerge(&other)
-	assert.ErrorContains(t, err, "multiple resources named bar (registered_model at bar.yml, registered_model at bar2.yml)")
-}
-
 // This test ensures that all resources have a custom marshaller and unmarshaller.
 // This is required because DABs resources map to Databricks APIs, and they do so
 // by embedding the corresponding Go SDK structs.

bundle/config/root.go

@@ -100,11 +100,6 @@ func LoadFromBytes(path string, raw []byte) (*Root, diag.Diagnostics) {
 	if err != nil {
 		return nil, diag.Errorf("failed to load %s: %v", path, err)
 	}
-
-	_, err = r.Resources.VerifyUniqueResourceIdentifiers()
-	if err != nil {
-		diags = diags.Extend(diag.FromErr(err))
-	}
 	return &r, diags
 }
 
@@ -281,12 +276,6 @@ func (r *Root) InitializeVariables(vars []string) error {
 }
 
 func (r *Root) Merge(other *Root) error {
-	// Check for safe merge, protecting against duplicate resource identifiers
-	err := r.Resources.VerifySafeMerge(&other.Resources)
-	if err != nil {
-		return err
-	}
-
 	// Merge dynamic configuration values.
 	return r.Mutate(func(root dyn.Value) (dyn.Value, error) {
 		return merge.Merge(root, other.value)

bundle/config/root_test.go

@@ -30,22 +30,6 @@ func TestRootLoad(t *testing.T) {
 	assert.Equal(t, "basic", root.Bundle.Name)
 }
 
-func TestDuplicateIdOnLoadReturnsError(t *testing.T) {
-	_, diags := Load("./testdata/duplicate_resource_names_in_root/databricks.yml")
-	assert.ErrorContains(t, diags.Error(), "multiple resources named foo (job at ./testdata/duplicate_resource_names_in_root/databricks.yml, pipeline at ./testdata/duplicate_resource_names_in_root/databricks.yml)")
-}
-
-func TestDuplicateIdOnMergeReturnsError(t *testing.T) {
-	root, diags := Load("./testdata/duplicate_resource_name_in_subconfiguration/databricks.yml")
-	require.NoError(t, diags.Error())
-
-	other, diags := Load("./testdata/duplicate_resource_name_in_subconfiguration/resources.yml")
-	require.NoError(t, diags.Error())
-
-	err := root.Merge(other)
-	assert.ErrorContains(t, err, "multiple resources named foo (job at ./testdata/duplicate_resource_name_in_subconfiguration/databricks.yml, pipeline at ./testdata/duplicate_resource_name_in_subconfiguration/resources.yml)")
-}
-
 func TestInitializeVariables(t *testing.T) {
 	fooDefault := "abc"
 	root := &Root{

bundle/config/validate/unique_resource_keys.go

@@ -0,0 +1,116 @@
+package validate
+
+import (
+	"context"
+	"fmt"
+	"slices"
+	"sort"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/dyn"
+)
+
+// This mutator validates that:
+//
+//  1. Each resource key is unique across different resource types. No two resources
+//     of the same type can have the same key. This is because command like "bundle run"
+//     rely on the resource key to identify the resource to run.
+//     Eg: jobs.foo and pipelines.foo are not allowed simultaneously.
+//
+//  2. Each resource definition is contained within a single file, and is not spread
+//     across multiple files. Note: This is not applicable to resource configuration
+//     defined in a target override. That is why this mutator MUST run before the target
+//     overrides are merged.
+func UniqueResourceKeys() bundle.Mutator {
+	return &uniqueResourceKeys{}
+}
+
+type uniqueResourceKeys struct{}
+
+func (m *uniqueResourceKeys) Name() string {
+	return "validate:unique_resource_keys"
+}
+
+func (m *uniqueResourceKeys) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagnostics {
+	diags := diag.Diagnostics{}
+
+	type metadata struct {
+		locations []dyn.Location
+		paths     []dyn.Path
+	}
+
+	// Maps of resource key to the paths and locations the resource is defined at.
+	resourceMetadata := map[string]*metadata{}
+
+	rv := b.Config.Value().Get("resources")
+
+	// return early if no resources are defined or the resources block is empty.
+	if rv.Kind() == dyn.KindInvalid || rv.Kind() == dyn.KindNil {
+		return diags
+	}
+
+	// Gather the paths and locations of all resources.
+	_, err := dyn.MapByPattern(
+		rv,
+		dyn.NewPattern(dyn.AnyKey(), dyn.AnyKey()),
+		func(p dyn.Path, v dyn.Value) (dyn.Value, error) {
+			// The key for the resource. Eg: "my_job" for jobs.my_job.
+			k := p[1].Key()
+
+			m, ok := resourceMetadata[k]
+			if !ok {
+				m = &metadata{
+					paths:     []dyn.Path{},
+					locations: []dyn.Location{},
+				}
+			}
+
+			// dyn.Path under the hood is a slice. The code that walks the configuration
+			// tree uses the same underlying slice to track the path as it walks
+			// the tree. So, we need to clone it here.
+			m.paths = append(m.paths, slices.Clone(p))
+			m.locations = append(m.locations, v.Locations()...)
+
+			resourceMetadata[k] = m
+			return v, nil
+		},
+	)
+	if err != nil {
+		return diag.FromErr(err)
+	}
+
+	for k, v := range resourceMetadata {
+		if len(v.locations) <= 1 {
+			continue
+		}
+
+		// Sort the locations and paths for consistent error messages. This helps
+		// with unit testing.
+		sort.Slice(v.locations, func(i, j int) bool {
+			l1 := v.locations[i]
+			l2 := v.locations[j]
+
+			if l1.File != l2.File {
+				return l1.File < l2.File
+			}
+			if l1.Line != l2.Line {
+				return l1.Line < l2.Line
+			}
+			return l1.Column < l2.Column
+		})
+		sort.Slice(v.paths, func(i, j int) bool {
+			return v.paths[i].String() < v.paths[j].String()
+		})
+
+		// If there are multiple resources with the same key, report an error.
+		diags = append(diags, diag.Diagnostic{
+			Severity:  diag.Error,
+			Summary:   fmt.Sprintf("multiple resources have been defined with the same key: %s", k),
+			Locations: v.locations,
+			Paths:     v.paths,
+		})
+	}
+
+	return diags
+}

bundle/tests/conflicting_resource_ids_test.go

@@ -1,42 +0,0 @@
-package config_tests
-
-import (
-	"context"
-	"fmt"
-	"path/filepath"
-	"testing"
-
-	"github.com/databricks/cli/bundle"
-	"github.com/databricks/cli/bundle/phases"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestConflictingResourceIdsNoSubconfig(t *testing.T) {
-	ctx := context.Background()
-	b, err := bundle.Load(ctx, "./conflicting_resource_ids/no_subconfigurations")
-	require.NoError(t, err)
-	diags := bundle.Apply(ctx, b, phases.Load())
-	bundleConfigPath := filepath.FromSlash("conflicting_resource_ids/no_subconfigurations/databricks.yml")
-	assert.ErrorContains(t, diags.Error(), fmt.Sprintf("multiple resources named foo (job at %s, pipeline at %s)", bundleConfigPath, bundleConfigPath))
-}
-
-func TestConflictingResourceIdsOneSubconfig(t *testing.T) {
-	ctx := context.Background()
-	b, err := bundle.Load(ctx, "./conflicting_resource_ids/one_subconfiguration")
-	require.NoError(t, err)
-	diags := bundle.Apply(ctx, b, phases.Load())
-	bundleConfigPath := filepath.FromSlash("conflicting_resource_ids/one_subconfiguration/databricks.yml")
-	resourcesConfigPath := filepath.FromSlash("conflicting_resource_ids/one_subconfiguration/resources.yml")
-	assert.ErrorContains(t, diags.Error(), fmt.Sprintf("multiple resources named foo (job at %s, pipeline at %s)", bundleConfigPath, resourcesConfigPath))
-}
-
-func TestConflictingResourceIdsTwoSubconfigs(t *testing.T) {
-	ctx := context.Background()
-	b, err := bundle.Load(ctx, "./conflicting_resource_ids/two_subconfigurations")
-	require.NoError(t, err)
-	diags := bundle.Apply(ctx, b, phases.Load())
-	resources1ConfigPath := filepath.FromSlash("conflicting_resource_ids/two_subconfigurations/resources1.yml")
-	resources2ConfigPath := filepath.FromSlash("conflicting_resource_ids/two_subconfigurations/resources2.yml")
-	assert.ErrorContains(t, diags.Error(), fmt.Sprintf("multiple resources named foo (job at %s, pipeline at %s)", resources1ConfigPath, resources2ConfigPath))
-}

bundle/tests/validate/duplicate_resource_name_in_multiple_locations/databricks.yml

@@ -4,10 +4,10 @@ bundle:
 workspace:
   profile: test
 
+include:
+  - ./*.yml
+
 resources:
   jobs:
     foo:
-      name: job foo
+      name: job foo 1
-  pipelines:
-    foo:
-      name: pipeline foo

bundle/tests/validate/duplicate_resource_name_in_multiple_locations/resources1.yml

@@ -1,4 +1,8 @@
 resources:
+  jobs:
+    foo:
+      name: job foo 2
+
   pipelines:
     foo:
       name: pipeline foo

bundle/tests/validate/duplicate_resource_name_in_multiple_locations/resources2.yml

@@ -0,0 +1,8 @@
+resources:
+  jobs:
+    foo:
+      name: job foo 3
+
+  experiments:
+    foo:
+      name: experiment foo

bundle/tests/validate/duplicate_resource_name_in_subconfiguration/databricks.yml

@@ -5,7 +5,7 @@ workspace:
   profile: test
 
 include:
-  - "*.yml"
+  - ./resources.yml
 
 resources:
   jobs:

bundle/tests/validate/duplicate_resource_name_in_subconfiguration_job_and_job/databricks.yml

@@ -4,6 +4,9 @@ bundle:
 workspace:
   profile: test
 
+include:
+  - ./resources.yml
+
 resources:
   jobs:
     foo:

bundle/tests/validate/duplicate_resource_name_in_subconfiguration_job_and_job/resources.yml

@@ -0,0 +1,4 @@
+resources:
+  jobs:
+    foo:
+      name: job foo 2

bundle/tests/validate/duplicate_resource_names_in_root_job_and_experiment/databricks.yml

@@ -0,0 +1,18 @@
+bundle:
+  name: test
+
+workspace:
+  profile: test
+
+resources:
+  jobs:
+    foo:
+      name: job foo
+    bar:
+      name: job bar
+  pipelines:
+    baz:
+      name: pipeline baz
+  experiments:
+    foo:
+      name: experiment foo

bundle/tests/validate_test.go

@@ -0,0 +1,139 @@
+package config_tests
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/bundle/phases"
+	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/dyn"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidateUniqueResourceIdentifiers(t *testing.T) {
+	tcases := []struct {
+		name        string
+		diagnostics diag.Diagnostics
+	}{
+		{
+			name: "duplicate_resource_names_in_root_job_and_pipeline",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_root_job_and_pipeline/databricks.yml"), Line: 10, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_root_job_and_pipeline/databricks.yml"), Line: 13, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("jobs.foo"),
+						dyn.MustPathFromString("pipelines.foo"),
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate_resource_names_in_root_job_and_experiment",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_root_job_and_experiment/databricks.yml"), Line: 10, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_root_job_and_experiment/databricks.yml"), Line: 18, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("experiments.foo"),
+						dyn.MustPathFromString("jobs.foo"),
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate_resource_name_in_subconfiguration",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_subconfiguration/databricks.yml"), Line: 13, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_subconfiguration/resources.yml"), Line: 4, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("jobs.foo"),
+						dyn.MustPathFromString("pipelines.foo"),
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate_resource_name_in_subconfiguration_job_and_job",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_subconfiguration_job_and_job/databricks.yml"), Line: 13, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_subconfiguration_job_and_job/resources.yml"), Line: 4, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("jobs.foo"),
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate_resource_names_in_different_subconfiguations",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_different_subconfiguations/resources1.yml"), Line: 4, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_names_in_different_subconfiguations/resources2.yml"), Line: 4, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("jobs.foo"),
+						dyn.MustPathFromString("pipelines.foo"),
+					},
+				},
+			},
+		},
+		{
+			name: "duplicate_resource_name_in_multiple_locations",
+			diagnostics: diag.Diagnostics{
+				{
+					Severity: diag.Error,
+					Summary:  "multiple resources have been defined with the same key: foo",
+					Locations: []dyn.Location{
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_multiple_locations/databricks.yml"), Line: 13, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_multiple_locations/resources1.yml"), Line: 4, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_multiple_locations/resources1.yml"), Line: 8, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_multiple_locations/resources2.yml"), Line: 4, Column: 7},
+						{File: filepath.FromSlash("validate/duplicate_resource_name_in_multiple_locations/resources2.yml"), Line: 8, Column: 7},
+					},
+					Paths: []dyn.Path{
+						dyn.MustPathFromString("experiments.foo"),
+						dyn.MustPathFromString("jobs.foo"),
+						dyn.MustPathFromString("pipelines.foo"),
+					},
+				},
+			},
+		},
+	}
+
+	for _, tc := range tcases {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := context.Background()
+			b, err := bundle.Load(ctx, "./validate/"+tc.name)
+			require.NoError(t, err)
+
+			// The UniqueResourceKeys mutator is run as part of the Load phase.
+			diags := bundle.Apply(ctx, b, phases.Load())
+			assert.Equal(t, tc.diagnostics, diags)
+		})
+	}
+}

libs/dyn/mapping.go

@@ -46,7 +46,8 @@ func newMappingFromGoMap(vin map[string]Value) Mapping {
 	return m
 }
 
-// Pairs returns all the key-value pairs in the Mapping.
+// Pairs returns all the key-value pairs in the Mapping. The pairs are sorted by
+// their key in lexicographic order.
 func (m Mapping) Pairs() []Pair {
 	return m.pairs
 }