Emit warnings when conflicting configuration is specified

bundle/config/validate/conflicting_configuration.go

@@ -0,0 +1,72 @@
+package validate
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/dyn"
+)
+
+// This mutator emits warnings if a configuration value is being override by another
+// value in the configuration files, effectively making the configuration useless.
+func ConflictingConfiguration() bundle.ReadOnlyMutator {
+	return &conflictingConfiguration{}
+}
+
+type conflictingConfiguration struct{}
+
+func (v *conflictingConfiguration) Name() string {
+	return "validate:conflicting_configuration"
+}
+
+func isKindScalar(v dyn.Value) bool {
+	switch v.Kind() {
+	case dyn.KindString, dyn.KindInt, dyn.KindBool, dyn.KindFloat, dyn.KindTime, dyn.KindNil:
+		return true
+	default:
+		return false
+	}
+}
+
+func conflictingConfigurationWarning(v dyn.Value, p dyn.Path, rb bundle.ReadOnlyBundle) string {
+	loc := v.Location()
+	rel, err := filepath.Rel(rb.RootPath(), loc.File)
+	if err == nil {
+		loc.File = rel
+	}
+
+	yamlLocations := v.YamlLocations()
+	for i, yamlLocation := range yamlLocations {
+		rel, err := filepath.Rel(rb.RootPath(), yamlLocation.File)
+		if err == nil {
+			yamlLocations[i].File = rel
+		}
+	}
+
+	return fmt.Sprintf("Multiple values found for the same configuration %s. Only the value from location %s will be used. Locations found: %s", p.String(), loc, yamlLocations)
+}
+
+func (v *conflictingConfiguration) Apply(ctx context.Context, rb bundle.ReadOnlyBundle) diag.Diagnostics {
+	diags := diag.Diagnostics{}
+
+	_, err := dyn.Walk(rb.Config().Value(), func(p dyn.Path, v dyn.Value) (dyn.Value, error) {
+		if !isKindScalar(v) {
+			return v, nil
+		}
+
+		if len(v.YamlLocations()) >= 2 {
+			diags = diags.Append(diag.Diagnostic{
+				Severity: diag.Warning,
+				Summary:  conflictingConfigurationWarning(v, p, rb),
+				Location: v.Location(),
+				Path:     p,
+			})
+		}
+		return v, nil
+	})
+	diags = append(diags, diag.FromErr(err)...)
+	return diags
+}

bundle/config/validate/pre_initialize.go

@@ -0,0 +1,28 @@
+package validate
+
+import (
+	"context"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/libs/diag"
+)
+
+type preInitialize struct{}
+
+// Apply implements bundle.Mutator.
+func (v *preInitialize) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagnostics {
+	return bundle.ApplyReadOnly(ctx, bundle.ReadOnly(b), bundle.Parallel(
+		ConflictingConfiguration(),
+	))
+}
+
+// Name implements bundle.Mutator.
+func (v *preInitialize) Name() string {
+	return "validate:pre_initialize"
+}
+
+// Validations to perform before initialization of the bundle. These validations
+// are thus applied for most bundle commands.
+func PreInitialize() bundle.Mutator {
+	return &preInitialize{}
+}

bundle/phases/initialize.go

@@ -4,6 +4,7 @@ import (
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/config"
 	"github.com/databricks/cli/bundle/config/mutator"
+	"github.com/databricks/cli/bundle/config/validate"
 	"github.com/databricks/cli/bundle/deploy/metadata"
 	"github.com/databricks/cli/bundle/deploy/terraform"
 	"github.com/databricks/cli/bundle/permissions"
@@ -18,6 +19,7 @@ func Initialize() bundle.Mutator {
 	return newPhase(
 		"initialize",
 		[]bundle.Mutator{
+			validate.PreInitialize(),
 			mutator.RewriteSyncPaths(),
 			mutator.MergeJobClusters(),
 			mutator.MergeJobTasks(),

bundle/tests/validate/conflicting_configuration/databricks.yml

@@ -0,0 +1,9 @@
+bundle:
+  name: test warnings for conflicting configuration
+
+include:
+  - "*.yml"
+
+variables:
+  bar:
+    default: conflicts

bundle/tests/validate/conflicting_configuration/resources1.yml

@@ -0,0 +1,6 @@
+variables:
+  bar:
+    default: conflicts
+
+  baz:
+    default: conflicts

bundle/tests/validate/conflicting_configuration/resources2.yml

@@ -0,0 +1,3 @@
+variables:
+  baz:
+    default: conflicts

bundle/tests/validate_test.go

@@ -0,0 +1,42 @@
+package config_tests
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/bundle/config/validate"
+	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/dyn"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConflictingConfigurationValidate(t *testing.T) {
+	b := load(t, "validate/conflicting_configuration")
+
+	ctx := context.Background()
+	diags := bundle.ApplyReadOnly(ctx, bundle.ReadOnly(b), validate.ConflictingConfiguration())
+
+	assert.Len(t, diags, 2)
+	assert.Contains(t, diags, diag.Diagnostic{
+		Severity: diag.Warning,
+		Summary:  "Multiple values found for the same configuration variables.baz.default. Only the value from location resources2.yml:3:14 will be used. Locations found: [resources2.yml:3:14 resources1.yml:6:14]",
+		Location: dyn.Location{
+			File:   filepath.FromSlash("validate/conflicting_configuration/resources2.yml"),
+			Line:   3,
+			Column: 14,
+		},
+		Path: dyn.MustPathFromString("variables.baz.default"),
+	})
+	assert.Contains(t, diags, diag.Diagnostic{
+		Severity: diag.Warning,
+		Summary:  "Multiple values found for the same configuration variables.bar.default. Only the value from location resources1.yml:3:14 will be used. Locations found: [resources1.yml:3:14 databricks.yml:9:14]",
+		Location: dyn.Location{
+			File:   filepath.FromSlash("validate/conflicting_configuration/resources1.yml"),
+			Line:   3,
+			Column: 14,
+		},
+		Path: dyn.MustPathFromString("variables.bar.default"),
+	})
+}