improve error handling for SourceRootDirs

Previously, warnings about missing modules were printed directly to
stderr. Instead we can pass these messages along as errors using the
existing pathways.

Bug: 269457150
Test: m nothing
Test: add -external to PRODUCT_SOURCE_ROOT_DIRS and observe missing
  module errors
Change-Id: Ib6624b9edbd103247f7f6e6d4c3030f1959aa56c

context_test.go

@@ -1492,7 +1492,7 @@ func TestSourceRootDirs(t *testing.T) {
 				"foo_dir1",
 			},
 			expectedErrs: []string{
-				"Android.bp:2:2: \"foo\" depends on undefined module \"foo_dir1\"",
+				`Android.bp:2:2: module "foo" depends on skipped module "foo_dir1"; "foo_dir1" was defined in files(s) [dir1/Android.bp], but was skipped for reason(s) ["dir1/Android.bp" is a descendant of "dir1", and that path prefix was not included in PRODUCT_SOURCE_ROOT_DIRS]`,
 			},
 		},
 		{
@@ -1506,7 +1506,7 @@ func TestSourceRootDirs(t *testing.T) {
 				"foo_dir_ignored_special_case",
 			},
 			expectedErrs: []string{
-				"dir1/Android.bp:2:2: \"foo_dir1\" depends on undefined module \"foo_dir_ignored\"",
+				`dir1/Android.bp:2:2: module "foo_dir1" depends on skipped module "foo_dir_ignored"; "foo_dir_ignored" was defined in files(s) [dir_ignored/Android.bp], but was skipped for reason(s) ["dir_ignored/Android.bp" is a descendant of "", and that path prefix was not included in PRODUCT_SOURCE_ROOT_DIRS]`,
 			},
 		},
 		{
@@ -1520,7 +1520,7 @@ func TestSourceRootDirs(t *testing.T) {
 				"foo_dir_ignored",
 			},
 			expectedErrs: []string{
-				"dir1/Android.bp:2:2: \"foo_dir1\" depends on undefined module \"foo_dir_ignored\"",
+				"dir1/Android.bp:2:2: module \"foo_dir1\" depends on skipped module \"foo_dir_ignored\"; \"foo_dir_ignored\" was defined in files(s) [dir_ignored/Android.bp], but was skipped for reason(s) [\"dir_ignored/Android.bp\" is a descendant of \"\", and that path prefix was not included in PRODUCT_SOURCE_ROOT_DIRS]",
 			},
 		},
 	}
@@ -1536,8 +1536,8 @@ func TestSourceRootDirs(t *testing.T) {
 			_, actualErrs := ctx.ResolveDependencies(nil)
 
 			stringErrs := []string(nil)
-			for i := range actualErrs {
+			for _, err := range actualErrs {
-				stringErrs = append(stringErrs, fmt.Sprint(actualErrs[i]))
+				stringErrs = append(stringErrs, err.Error())
 			}
 			if !reflect.DeepEqual(tc.expectedErrs, stringErrs) {
 				t.Errorf("expected to find errors %v; got %v", tc.expectedErrs, stringErrs)

name_interface.go

@@ -16,7 +16,6 @@ package blueprint
 
 import (
 	"fmt"
-	"os"
 	"sort"
 	"strings"
 )
@@ -62,6 +61,9 @@ type NameInterface interface {
 	// Finds the module with the given name
 	ModuleFromName(moduleName string, namespace Namespace) (group ModuleGroup, found bool)
 
+	// Finds if the module with the given name was skipped
+	SkippedModuleFromName(moduleName string, namespace Namespace) (skipInfos []SkippedModuleInfo, skipped bool)
+
 	// Returns an error indicating that the given module could not be found.
 	// The error contains some diagnostic information about where the dependency can be found.
 	MissingDependencyError(depender string, dependerNamespace Namespace, depName string) (err error)
@@ -143,25 +145,14 @@ func (s *SimpleNameInterface) NewSkippedModule(ctx NamespaceContext, name string
 
 func (s *SimpleNameInterface) ModuleFromName(moduleName string, namespace Namespace) (group ModuleGroup, found bool) {
 	group, found = s.modules[moduleName]
-	skipInfos, skipped := s.skippedModules[moduleName]
-	if skipped {
-		filesFound := make([]string, 0, len(skipInfos))
-		reasons := make([]string, 0, len(skipInfos))
-		for _, info := range skipInfos {
-			filesFound = append(filesFound, info.filename)
-			reasons = append(reasons, info.reason)
-		}
-		fmt.Fprintf(
-			os.Stderr,
-			"module %q was defined in files(s) [%v], but was skipped for reason(s) [%v]\n",
-			moduleName,
-			strings.Join(filesFound, ", "),
-			strings.Join(reasons, "; "),
-		)
-	}
 	return group, found
 }
 
+func (s *SimpleNameInterface) SkippedModuleFromName(moduleName string, namespace Namespace) (skipInfos []SkippedModuleInfo, skipped bool) {
+	skipInfos, skipped = s.skippedModules[moduleName]
+	return
+}
+
 func (s *SimpleNameInterface) Rename(oldName string, newName string, namespace Namespace) (errs []error) {
 	existingGroup, exists := s.modules[newName]
 	if exists {
@@ -207,6 +198,23 @@ func (s *SimpleNameInterface) AllModules() []ModuleGroup {
 }
 
 func (s *SimpleNameInterface) MissingDependencyError(depender string, dependerNamespace Namespace, dependency string) (err error) {
+	skipInfos, skipped := s.SkippedModuleFromName(dependency, dependerNamespace)
+	if skipped {
+		filesFound := make([]string, 0, len(skipInfos))
+		reasons := make([]string, 0, len(skipInfos))
+		for _, info := range skipInfos {
+			filesFound = append(filesFound, info.filename)
+			reasons = append(reasons, info.reason)
+		}
+		return fmt.Errorf(
+			"module %q depends on skipped module %q; %q was defined in files(s) [%v], but was skipped for reason(s) [%v]",
+			depender,
+			dependency,
+			dependency,
+			strings.Join(filesFound, ", "),
+			strings.Join(reasons, "; "),
+		)
+	}
 	return fmt.Errorf("%q depends on undefined module %q", depender, dependency)
 }