bug: discovery parsing errors handling

config/config_partial.go

@@ -359,6 +359,14 @@ func PartialParseConfigString(ctx *ParsingContext, l log.Logger, configPath, con
 func PartialParseConfig(ctx *ParsingContext, l log.Logger, file *hclparse.File, includeFromChild *IncludeConfig) (*TerragruntConfig, error) {
 	errs := &errors.MultiError{}
 
+	// Detect and block deprecated configurations early, before attempting to parse.
+	// This ensures included configs with deprecated syntax get clear error messages
+	// instead of cryptic "Could not find Terragrunt configuration settings" errors.
+	// See: https://github.com/gruntwork-io/terragrunt/issues/4983
+	if err := DetectDeprecatedConfigurations(ctx, l, file); err != nil {
+		return nil, err
+	}
+
 	ctx = ctx.WithTrackInclude(nil)
 
 	// read unit files and add to context

internal/discovery/discovery.go

@@ -3,6 +3,7 @@ package discovery
 
 import (
 	"context"
+	stderrs "errors"
 	"io"
 	"io/fs"
 	"os"
@@ -514,6 +515,18 @@ func Parse(
 	//nolint: contextcheck
 	cfg, err = config.PartialParseConfigFile(parsingCtx, l, parseOpts.TerragruntConfigPath, nil)
 	if err != nil {
+		// Treat include-only/no-settings configs as non-fatal during discovery when suppression is enabled
+		if suppressParseErrors && containsNoSettingsError(err) {
+			l.Debugf("Skipping include-only config during discovery: %s", parseOpts.TerragruntConfigPath)
+
+			// Store an empty partial config to avoid nil dereferences in subsequent dependency discovery
+			if unit, ok := c.(*component.Unit); ok {
+				unit.StoreConfig(&config.TerragruntConfig{IsPartial: true})
+			}
+
+			return nil
+		}
+
 		if !suppressParseErrors || cfg == nil {
 			l.Debugf("Unrecoverable parse error for %s: %s", parseOpts.TerragruntConfigPath, err)
 
@@ -1000,9 +1013,12 @@ func (d *Discovery) Discover(
 
 			err := dependencyDiscovery.DiscoverAllDependencies(ctx, l, opts)
 			if err != nil {
-				l.Warnf("Parsing errors where encountered while discovering dependencies. They were suppressed, and can be found in the debug logs.")
+				l.Warnf("Suppressed parsing errors discovered while scanning dependencies. See debug logs for details.")
 
-				l.Debugf("Errors: %w", err)
+				// List underlying errors without %w to avoid confusing formatting like `%!w(...)`
+				for _, e := range errors.UnwrapErrors(err) {
+					l.Debugf("Parse error: %v", e)
+				}
 			}
 
 			components = dependencyDiscovery.components
@@ -1308,3 +1324,17 @@ func (h *hiddenDirMemo) contains(path string) bool {
 
 	return false
 }
+
+// containsNoSettingsError returns true if the provided error (possibly a joined/wrapped error)
+// contains a config-level error indicating there were no Terragrunt configuration settings
+// (e.g., include-only file) that should be treated as non-fatal during discovery.
+func containsNoSettingsError(err error) bool {
+	for _, e := range errors.UnwrapErrors(err) {
+		var target config.CouldNotResolveTerragruntConfigInFileError
+		if stderrs.As(e, &target) {
+			return true
+		}
+	}
+
+	return false
+}

internal/runner/runnerpool/controller.go

@@ -112,7 +112,7 @@ func (dr *Controller) Run(ctx context.Context, l log.Logger) error {
 
 			for _, e := range readyEntries {
 				// log debug which entry is running
-				l.Debugf("Runner Pool Controller: running %s", e.Component.Path)
+				l.Debugf("Runner Pool Controller: running %s", e.Component.Path())
 				dr.q.SetEntryStatus(e, queue.StatusRunning)
 
 				sem <- struct{}{}
@@ -133,7 +133,7 @@ func (dr *Controller) Run(ctx context.Context, l log.Logger) error {
 					unit := dr.unitsMap[ent.Component.Path()]
 					if unit == nil {
 						err := errors.Errorf("unit for path %s not found in discovered units", ent.Component.Path())
-						l.Errorf("Runner Pool Controller: unit for path %s not found in discovered units, skipping execution", ent.Component.Path)
+						l.Errorf("Runner Pool Controller: unit for path %s not found in discovered units, skipping execution", ent.Component.Path())
 						dr.q.FailEntry(ent)
 						results.Store(ent.Component.Path(), err)
 
@@ -144,13 +144,13 @@ func (dr *Controller) Run(ctx context.Context, l log.Logger) error {
 					results.Store(ent.Component.Path(), err)
 
 					if err != nil {
-						l.Debugf("Runner Pool Controller: %s failed", ent.Component.Path)
+						l.Debugf("Runner Pool Controller: %s failed", ent.Component.Path())
 						dr.q.FailEntry(ent)
 
 						return
 					}
 
-					l.Debugf("Runner Pool Controller: %s succeeded", ent.Component.Path)
+					l.Debugf("Runner Pool Controller: %s succeeded", ent.Component.Path())
 					dr.q.SetEntryStatus(ent, queue.StatusSucceeded)
 				}(e)
 			}

test/fixtures/parsing/exposed-include-with-deprecated-inputs/child/terragrunt.hcl

@@ -0,0 +1,32 @@
+# Child configuration that includes compcommon with expose = true
+# This should trigger the bug where the deprecated syntax in compcommon isn't detected
+
+include "root" {
+  path = find_in_parent_folders("root.hcl")
+  expose = true
+}
+
+include "compcommon" {
+  path = find_in_parent_folders("compcommon.hcl")
+  expose = true
+}
+
+terraform {
+  source = "git::[email protected]:gruntwork-io/terragrunt.git//test/fixtures/download/hello-world"
+}
+
+dependency "service" {
+  config_path = "../dep"
+  mock_outputs_allowed_terraform_commands = ["validate", "plan"]
+  mock_outputs = {
+    some_value = "mock-service-value"
+  }
+  mock_outputs_merge_strategy_with_state = "shallow"
+}
+
+# Reference the exposed include - this will try to evaluate compcommon
+# which contains the deprecated syntax
+inputs = {
+  from_common = try(include.compcommon.inputs.value_from_dep, "fallback")
+  from_service = dependency.service.outputs.some_value
+}

test/fixtures/parsing/exposed-include-with-deprecated-inputs/compcommon.hcl

@@ -0,0 +1,16 @@
+# Common configuration that uses deprecated dependency.*.inputs.* syntax
+# This should trigger the bug when included with expose = true
+
+dependency "dep" {
+  config_path = "../dep"
+  mock_outputs_allowed_terraform_commands = ["validate", "plan"]
+  mock_outputs = {
+    some_value = "mock-value"
+  }
+  mock_outputs_merge_strategy_with_state = "shallow"
+}
+
+# Using deprecated syntax - this should be caught but isn't in partial parse
+inputs = {
+  value_from_dep = dependency.dep.inputs.some_value
+}

test/fixtures/parsing/exposed-include-with-deprecated-inputs/dep/terragrunt.hcl

@@ -0,0 +1,8 @@
+# Mock dependency configuration
+terraform {
+  source = "git::[email protected]:gruntwork-io/terragrunt.git//test/fixtures/download/hello-world"
+}
+
+inputs = {
+  some_value = "test-value"
+}

test/fixtures/parsing/exposed-include-with-deprecated-inputs/root.hcl

@@ -0,0 +1,4 @@
+# Minimal root configuration
+locals {
+  region = "us-east-1"
+}

test/fixtures/regressions/parsing-run-all-with-generate/root.hcl

@@ -0,0 +1,29 @@
+locals {
+  aws_provider_version = "6.15.0"
+}
+
+# Generate an AWS provider block
+generate "provider" {
+  path      = "provider.tf"
+  if_exists = "overwrite_terragrunt"
+  contents  = <<EOF
+provider "aws" {
+  region = "us-east-1"
+}
+EOF
+}
+
+generate "versions_override" {
+  path      = "versions_override.tf"
+  if_exists = "overwrite_terragrunt"
+  contents  = <<EOF
+terraform {
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "${local.aws_provider_version}"
+    }
+  }
+}
+EOF
+}

test/fixtures/regressions/parsing-run-all-with-generate/services-info/main.tf

@@ -0,0 +1,26 @@
+variable "desired_count" {
+  description = "The desired count of the ECS Service"
+  type        = map(number)
+}
+
+variable "use_api_image" {
+  description = "Whether to use the API image"
+  type        = map(bool)
+}
+
+resource "null_resource" "services_info" {
+  triggers = {
+    desired_count = jsonencode(var.desired_count)
+    use_api_image = jsonencode(var.use_api_image)
+  }
+}
+
+output "desired_count" {
+  description = "The desired count of the ECS Service"
+  value       = var.desired_count
+}
+
+output "use_api_image" {
+  description = "Whether to use the API image"
+  value       = var.use_api_image
+}

test/fixtures/regressions/parsing-run-all-with-generate/services-info/terragrunt.hcl

@@ -0,0 +1,37 @@
+include "root" {
+  path = find_in_parent_folders("root.hcl")
+  expose = true
+}
+
+terraform {
+  source = "${get_terragrunt_dir()}/."
+}
+
+dependency "service-test1" {
+  config_path = "../services/test1"
+  mock_outputs_allowed_terraform_commands = ["validate", "plan"]
+  mock_outputs = {
+    service_desired_count_initial_value = null
+    service_name = "FAKE-SERVICE-1"
+    docker_images = [
+        {
+            repository = "123456789012.dkr.ecr.us-east-1.amazonaws.com/test1-FAKE"
+        }
+    ]
+  }
+  mock_outputs_merge_strategy_with_state = "shallow"
+}
+
+locals {
+  repository_url = "123456789012.dkr.ecr.us-east-1.amazonaws.com/api-FAKE"
+  name = "services-info"
+}
+
+inputs = {
+  desired_count = {
+    test1 = dependency.service-test1.outputs.service_desired_count_initial_value
+  }
+  use_api_image = {
+    test1 = dependency.service-test1.outputs.docker_images[0].repository == local.repository_url
+  }
+}

test/fixtures/regressions/parsing-run-all-with-generate/services/test1/main.tf

@@ -0,0 +1,19 @@
+variable "name" {
+  type = string
+}
+
+output "service_name" {
+  value = var.name
+}
+
+output "service_desired_count_initial_value" {
+  value = 1
+}
+
+output "docker_images" {
+  value = [
+    {
+      repository = "123456789012.dkr.ecr.us-east-1.amazonaws.com/${var.name}-FAKE"
+    }
+  ]
+}

test/fixtures/regressions/parsing-run-all-with-generate/services/test1/terragrunt.hcl

@@ -0,0 +1,16 @@
+include "root" {
+  path = find_in_parent_folders("root.hcl")
+  expose = true
+}
+
+terraform {
+  source = "${get_terragrunt_dir()}/."
+}
+
+locals {
+    name = "service1"
+}
+
+inputs = {
+    name = local.name
+}

test/integration_parse_test.go

@@ -34,6 +34,7 @@ var knownBadFiles = []string{
 	"fixtures/hclfmt-errors/invalid-character/terragrunt.hcl",
 	"fixtures/hclfmt-errors/invalid-key/terragrunt.hcl",
 	"fixtures/hclvalidate/second/a/terragrunt.hcl",
+	"fixtures/parsing/exposed-include-with-deprecated-inputs/compcommon.hcl",
 	"fixtures/scaffold/with-shell-and-hooks/.boilerplate/terragrunt.hcl",
 	"fixtures/scaffold/with-shell-commands/.boilerplate/terragrunt.hcl",
 }