Merge "Do not dump metrics if reproxy was never started"
diff --git a/Android.bp b/Android.bp
index 7c50047..380a388 100644
--- a/Android.bp
+++ b/Android.bp
@@ -50,6 +50,7 @@
     name: "device_kernel_headers",
     vendor: true,
     recovery_available: true,
+    min_sdk_version: "apex_inherit",
 }
 
 cc_genrule {
diff --git a/android/api_levels.go b/android/api_levels.go
index de56625..27a3b7f 100644
--- a/android/api_levels.go
+++ b/android/api_levels.go
@@ -18,6 +18,8 @@
 	"encoding/json"
 	"fmt"
 	"strconv"
+
+	"android/soong/starlark_fmt"
 )
 
 func init() {
@@ -380,3 +382,21 @@
 	apiLevelsJson := GetApiLevelsJson(ctx)
 	createApiLevelsJson(ctx, apiLevelsJson, apiLevelsMap)
 }
+
+func printApiLevelsStarlarkDict(config Config) string {
+	apiLevelsMap := GetApiLevelsMap(config)
+	valDict := make(map[string]string, len(apiLevelsMap))
+	for k, v := range apiLevelsMap {
+		valDict[k] = strconv.Itoa(v)
+	}
+	return starlark_fmt.PrintDict(valDict, 0)
+}
+
+func StarlarkApiLevelConfigs(config Config) string {
+	return fmt.Sprintf(`# GENERATED FOR BAZEL FROM SOONG. DO NOT EDIT.
+_api_levels = %s
+
+api_levels = _api_levels
+`, printApiLevelsStarlarkDict(config),
+	)
+}
\ No newline at end of file
diff --git a/android/bazel.go b/android/bazel.go
index 97226c6..0617367 100644
--- a/android/bazel.go
+++ b/android/bazel.go
@@ -300,7 +300,7 @@
 		"external/bouncycastle":                              Bp2BuildDefaultTrue,
 		"external/brotli":                                    Bp2BuildDefaultTrue,
 		"external/conscrypt":                                 Bp2BuildDefaultTrue,
-		"external/e2fsprogs/lib":                             Bp2BuildDefaultTrueRecursively,
+		"external/e2fsprogs":                                 Bp2BuildDefaultTrueRecursively,
 		"external/error_prone":                               Bp2BuildDefaultTrueRecursively,
 		"external/fmtlib":                                    Bp2BuildDefaultTrueRecursively,
 		"external/google-benchmark":                          Bp2BuildDefaultTrueRecursively,
diff --git a/bp2build/cc_binary_conversion_test.go b/bp2build/cc_binary_conversion_test.go
index 8d94079..17337f0 100644
--- a/bp2build/cc_binary_conversion_test.go
+++ b/bp2build/cc_binary_conversion_test.go
@@ -15,12 +15,13 @@
 package bp2build
 
 import (
-	"android/soong/android"
-	"android/soong/cc"
-	"android/soong/genrule"
 	"fmt"
 	"strings"
 	"testing"
+
+	"android/soong/android"
+	"android/soong/cc"
+	"android/soong/genrule"
 )
 
 const (
@@ -127,6 +128,8 @@
         keep_symbols_list: ["symbol"],
         none: true,
     },
+    sdk_version: "current",
+    min_sdk_version: "29",
 }
 `,
 		targets: []testBazelTarget{
@@ -150,6 +153,8 @@
         "keep_symbols_list": ["symbol"],
         "none": True,
     }`,
+        "sdk_version": `"current"`,
+        "min_sdk_version": `"29"`,
 			},
 			},
 		},
diff --git a/bp2build/cc_library_conversion_test.go b/bp2build/cc_library_conversion_test.go
index 8fde655..d84e156 100644
--- a/bp2build/cc_library_conversion_test.go
+++ b/bp2build/cc_library_conversion_test.go
@@ -115,6 +115,8 @@
         },
     },
     include_build_directory: false,
+    sdk_version: "current",
+    min_sdk_version: "29",
 }
 `,
 		expectedBazelTargets: makeCcLibraryTargets("foo-lib", attrNameToString{
@@ -140,6 +142,8 @@
         "//build/bazel/platforms/os:linux_bionic": ["bionic.cpp"],
         "//conditions:default": [],
     })`,
+      "sdk_version": `"current"`,
+      "min_sdk_version": `"29"`,
 		}),
 	})
 }
diff --git a/bp2build/cc_library_headers_conversion_test.go b/bp2build/cc_library_headers_conversion_test.go
index e4cfa35..e5bb120 100644
--- a/bp2build/cc_library_headers_conversion_test.go
+++ b/bp2build/cc_library_headers_conversion_test.go
@@ -112,6 +112,8 @@
             export_include_dirs: ["arch_x86_64_exported_include_dir"],
         },
     },
+    sdk_version: "current",
+    min_sdk_version: "29",
 
     // TODO: Also support export_header_lib_headers
 }`,
@@ -130,6 +132,8 @@
         ":lib-1",
         ":lib-2",
     ]`,
+        "sdk_version": `"current"`,
+        "min_sdk_version": `"29"`,
 			}),
 		},
 	})
diff --git a/bp2build/cc_library_shared_conversion_test.go b/bp2build/cc_library_shared_conversion_test.go
index 78192fe..22c9dfe 100644
--- a/bp2build/cc_library_shared_conversion_test.go
+++ b/bp2build/cc_library_shared_conversion_test.go
@@ -136,6 +136,8 @@
         "header_lib_1",
         "header_lib_2"
     ],
+    sdk_version: "current",
+    min_sdk_version: "29",
 
     // TODO: Also support export_header_lib_headers
 }`,
@@ -174,6 +176,8 @@
         ":whole_static_lib_1",
         ":whole_static_lib_2",
     ]`,
+        "sdk_version": `"current"`,
+        "min_sdk_version": `"29"`,
 			}),
 		},
 	})
diff --git a/bp2build/cc_library_static_conversion_test.go b/bp2build/cc_library_static_conversion_test.go
index 205bf4d..be10e86 100644
--- a/bp2build/cc_library_static_conversion_test.go
+++ b/bp2build/cc_library_static_conversion_test.go
@@ -166,6 +166,8 @@
         "header_lib_1",
         "header_lib_2"
     ],
+    sdk_version: "current",
+    min_sdk_version: "29",
 
     // TODO: Also support export_header_lib_headers
 }`,
@@ -202,6 +204,8 @@
         ":whole_static_lib_1",
         ":whole_static_lib_2",
     ]`,
+        "sdk_version": `"current"`,
+        "min_sdk_version": `"29"`,
 			}),
 		},
 	})
diff --git a/bp2build/cc_object_conversion_test.go b/bp2build/cc_object_conversion_test.go
index 0a6c317..ea58086 100644
--- a/bp2build/cc_object_conversion_test.go
+++ b/bp2build/cc_object_conversion_test.go
@@ -55,6 +55,8 @@
         "a/b/*.c"
     ],
     exclude_srcs: ["a/b/exclude.c"],
+    sdk_version: "current",
+    min_sdk_version: "29",
 }
 `,
 		expectedBazelTargets: []string{
@@ -71,6 +73,8 @@
     ]`,
 				"srcs":                `["a/b/c.c"]`,
 				"system_dynamic_deps": `[]`,
+        "sdk_version": `"current"`,
+        "min_sdk_version": `"29"`,
 			}),
 		},
 	})
diff --git a/bp2build/conversion.go b/bp2build/conversion.go
index 3ab846b..91e614d 100644
--- a/bp2build/conversion.go
+++ b/bp2build/conversion.go
@@ -36,6 +36,7 @@
 	}
 	files = append(files, newFile("api_levels", GeneratedBuildFileName, `exports_files(["api_levels.json"])`))
 	files = append(files, newFile("api_levels", "api_levels.json", string(apiLevelsContent)))
+	files = append(files, newFile("api_levels", "api_levels.bzl", android.StarlarkApiLevelConfigs(cfg)))
 
 	return files
 }
diff --git a/bp2build/conversion_test.go b/bp2build/conversion_test.go
index c94a923..d65ece8 100644
--- a/bp2build/conversion_test.go
+++ b/bp2build/conversion_test.go
@@ -114,6 +114,10 @@
 			dir:      "api_levels",
 			basename: "api_levels.json",
 		},
+		{
+			dir:      "api_levels",
+			basename: "api_levels.bzl",
+		},
 	}
 
 	if len(files) != len(expectedFilePaths) {
diff --git a/cc/binary.go b/cc/binary.go
index 9262f21..89e7262 100644
--- a/cc/binary.go
+++ b/cc/binary.go
@@ -630,6 +630,8 @@
 		},
 
 		Features: baseAttrs.features,
+
+		sdkAttributes: bp2BuildParseSdkAttributes(m),
 	}
 
 	ctx.CreateBazelTargetModule(bazel.BazelTargetModuleProperties{
@@ -673,4 +675,6 @@
 	Strip stripAttributes
 
 	Features bazel.StringListAttribute
+
+	sdkAttributes
 }
diff --git a/cc/bp2build.go b/cc/bp2build.go
index 379d6f2..93d11c7 100644
--- a/cc/bp2build.go
+++ b/cc/bp2build.go
@@ -52,6 +52,8 @@
 	System_dynamic_deps bazel.LabelListAttribute
 
 	Enabled bazel.BoolAttribute
+
+	sdkAttributes
 }
 
 // groupSrcsByExtension partitions `srcs` into groups based on file extension.
@@ -539,6 +541,18 @@
 	}
 }
 
+func bp2BuildParseSdkAttributes(module *Module) sdkAttributes {
+	return sdkAttributes {
+		Sdk_version: module.Properties.Sdk_version,
+		Min_sdk_version: module.Properties.Min_sdk_version,
+	}
+}
+
+type sdkAttributes struct {
+	Sdk_version     *string
+	Min_sdk_version *string
+}
+
 // Convenience struct to hold all attributes parsed from linker properties.
 type linkerAttributes struct {
 	deps                             bazel.LabelListAttribute
diff --git a/cc/library.go b/cc/library.go
index 5fa3471..035a90e 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -316,6 +316,7 @@
 		Implementation_whole_archive_deps: linkerAttrs.implementationWholeArchiveDeps,
 		Whole_archive_deps:                *linkerAttrs.wholeArchiveDeps.Clone().Append(staticAttrs.Whole_archive_deps),
 		System_dynamic_deps:               *linkerAttrs.systemDynamicDeps.Clone().Append(staticAttrs.System_dynamic_deps),
+		sdkAttributes:                     bp2BuildParseSdkAttributes(m),
 	}
 
 	sharedCommonAttrs := staticOrSharedAttributes{
@@ -331,6 +332,7 @@
 		Implementation_dynamic_deps: *linkerAttrs.implementationDynamicDeps.Clone().Append(sharedAttrs.Implementation_dynamic_deps),
 		Whole_archive_deps:          *linkerAttrs.wholeArchiveDeps.Clone().Append(sharedAttrs.Whole_archive_deps),
 		System_dynamic_deps:         *linkerAttrs.systemDynamicDeps.Clone().Append(sharedAttrs.System_dynamic_deps),
+		sdkAttributes:               bp2BuildParseSdkAttributes(m),
 	}
 
 	staticTargetAttrs := &bazelCcLibraryStaticAttributes{
@@ -2481,6 +2483,7 @@
 		Whole_archive_deps:                linkerAttrs.wholeArchiveDeps,
 		Implementation_whole_archive_deps: linkerAttrs.implementationWholeArchiveDeps,
 		System_dynamic_deps:               linkerAttrs.systemDynamicDeps,
+		sdkAttributes:                     bp2BuildParseSdkAttributes(module),
 	}
 
 	var attrs interface{}
diff --git a/cc/library_headers.go b/cc/library_headers.go
index 5d38fba..41ebcc7 100644
--- a/cc/library_headers.go
+++ b/cc/library_headers.go
@@ -117,6 +117,7 @@
 	Deps                     bazel.LabelListAttribute
 	Implementation_deps      bazel.LabelListAttribute
 	System_dynamic_deps      bazel.LabelListAttribute
+	sdkAttributes
 }
 
 func libraryHeadersBp2Build(ctx android.TopDownMutatorContext, module *Module) {
@@ -132,6 +133,7 @@
 		Deps:                     linkerAttrs.deps,
 		System_dynamic_deps:      linkerAttrs.systemDynamicDeps,
 		Hdrs:                     baseAttributes.hdrs,
+		sdkAttributes:            bp2BuildParseSdkAttributes(module),
 	}
 
 	props := bazel.BazelTargetModuleProperties{
diff --git a/cc/object.go b/cc/object.go
index fdd0b11..bd5bd45 100644
--- a/cc/object.go
+++ b/cc/object.go
@@ -133,6 +133,7 @@
 	Absolute_includes   bazel.StringListAttribute
 	Stl                 *string
 	Linker_script       bazel.LabelAttribute
+	sdkAttributes
 }
 
 // objectBp2Build is the bp2build converter from cc_object modules to the
@@ -191,6 +192,7 @@
 		Absolute_includes:   compilerAttrs.absoluteIncludes,
 		Stl:                 compilerAttrs.stl,
 		Linker_script:       linkerScript,
+		sdkAttributes:       bp2BuildParseSdkAttributes(m),
 	}
 
 	props := bazel.BazelTargetModuleProperties{
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index eddcb61..c3a5d5f 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -140,7 +140,7 @@
 	BootclasspathFragmentsDepsProperties
 }
 
-type SourceOnlyBootclasspathProperties struct {
+type HiddenApiPackageProperties struct {
 	Hidden_api struct {
 		// Contains prefixes of a package hierarchy that is provided solely by this
 		// bootclasspath_fragment.
@@ -149,6 +149,14 @@
 		// hidden API flags. See split_packages property for more details.
 		Package_prefixes []string
 
+		// A list of individual packages that are provided solely by this
+		// bootclasspath_fragment but which cannot be listed in package_prefixes
+		// because there are sub-packages which are provided by other modules.
+		//
+		// This should only be used for legacy packages. New packages should be
+		// covered by a package prefix.
+		Single_packages []string
+
 		// The list of split packages provided by this bootclasspath_fragment.
 		//
 		// A split package is one that contains classes which are provided by multiple
@@ -208,6 +216,11 @@
 	}
 }
 
+type SourceOnlyBootclasspathProperties struct {
+	HiddenApiPackageProperties
+	Coverage HiddenApiPackageProperties
+}
+
 type BootclasspathFragmentModule struct {
 	android.ModuleBase
 	android.ApexModuleBase
@@ -271,6 +284,12 @@
 				ctx.PropertyErrorf("coverage", "error trying to append coverage specific properties: %s", err)
 				return
 			}
+
+			err = proptools.AppendProperties(&m.sourceOnlyProperties.HiddenApiPackageProperties, &m.sourceOnlyProperties.Coverage, nil)
+			if err != nil {
+				ctx.PropertyErrorf("coverage", "error trying to append hidden api coverage specific properties: %s", err)
+				return
+			}
 		}
 
 		// Initialize the contents property from the image_name.
@@ -731,7 +750,8 @@
 	// TODO(b/192868581): Remove once the source and prebuilts provide a signature patterns file of
 	//  their own.
 	if output.SignaturePatternsPath == nil {
-		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath, []string{"*"}, nil)
+		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(
+			ctx, output.AllFlagsPath, []string{"*"}, nil, nil)
 	}
 
 	// Initialize a HiddenAPIInfo structure.
@@ -806,11 +826,13 @@
 	// signature patterns.
 	splitPackages := b.sourceOnlyProperties.Hidden_api.Split_packages
 	packagePrefixes := b.sourceOnlyProperties.Hidden_api.Package_prefixes
-	if splitPackages != nil || packagePrefixes != nil {
+	singlePackages := b.sourceOnlyProperties.Hidden_api.Single_packages
+	if splitPackages != nil || packagePrefixes != nil || singlePackages != nil {
 		if splitPackages == nil {
 			splitPackages = []string{"*"}
 		}
-		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(ctx, output.AllFlagsPath, splitPackages, packagePrefixes)
+		output.SignaturePatternsPath = buildRuleSignaturePatternsFile(
+			ctx, output.AllFlagsPath, splitPackages, packagePrefixes, singlePackages)
 	}
 
 	return output
diff --git a/java/dexpreopt_bootjars.go b/java/dexpreopt_bootjars.go
index ee43218..3d91aec 100644
--- a/java/dexpreopt_bootjars.go
+++ b/java/dexpreopt_bootjars.go
@@ -284,6 +284,9 @@
 
 	// Target-dependent fields.
 	variants []*bootImageVariant
+
+	// Path of the preloaded classes file.
+	preloadedClassesFile string
 }
 
 // Target-dependent description of a boot image.
@@ -686,6 +689,13 @@
 		cmd.FlagWithArg("--base=", ctx.Config().LibartImgDeviceBaseAddress())
 	}
 
+	// We always expect a preloaded classes file to be available. However, if we cannot find it, it's
+	// OK to not pass the flag to dex2oat.
+	preloadedClassesPath := android.ExistentPathForSource(ctx, image.preloadedClassesFile)
+	if preloadedClassesPath.Valid() {
+		cmd.FlagWithInput("--preloaded-classes=", preloadedClassesPath.Path())
+	}
+
 	cmd.
 		FlagForEachInput("--dex-file=", image.dexPaths.Paths()).
 		FlagForEachArg("--dex-location=", image.dexLocations).
diff --git a/java/dexpreopt_config.go b/java/dexpreopt_config.go
index 21e1d12..4d0bd09 100644
--- a/java/dexpreopt_config.go
+++ b/java/dexpreopt_config.go
@@ -62,18 +62,20 @@
 			installDirOnDevice:       "system/framework",
 			profileInstallPathInApex: "etc/boot-image.prof",
 			modules:                  artModules,
+			preloadedClassesFile:     "art/build/boot/preloaded-classes",
 		}
 
 		// Framework config for the boot image extension.
 		// It includes framework libraries and depends on the ART config.
 		frameworkSubdir := "system/framework"
 		frameworkCfg := bootImageConfig{
-			extends:            &artCfg,
-			name:               frameworkBootImageName,
-			stem:               "boot",
-			installDirOnHost:   frameworkSubdir,
-			installDirOnDevice: frameworkSubdir,
-			modules:            frameworkModules,
+			extends:              &artCfg,
+			name:                 frameworkBootImageName,
+			stem:                 "boot",
+			installDirOnHost:     frameworkSubdir,
+			installDirOnDevice:   frameworkSubdir,
+			modules:              frameworkModules,
+			preloadedClassesFile: "frameworks/base/config/preloaded-classes",
 		}
 
 		return map[string]*bootImageConfig{
diff --git a/java/hiddenapi_modular.go b/java/hiddenapi_modular.go
index 0cc960d..95ded34 100644
--- a/java/hiddenapi_modular.go
+++ b/java/hiddenapi_modular.go
@@ -943,7 +943,9 @@
 
 // buildRuleSignaturePatternsFile creates a rule to generate a file containing the set of signature
 // patterns that will select a subset of the monolithic flags.
-func buildRuleSignaturePatternsFile(ctx android.ModuleContext, flagsPath android.Path, splitPackages []string, packagePrefixes []string) android.Path {
+func buildRuleSignaturePatternsFile(
+	ctx android.ModuleContext, flagsPath android.Path,
+	splitPackages []string, packagePrefixes []string, singlePackages []string) android.Path {
 	patternsFile := android.PathForModuleOut(ctx, "modular-hiddenapi", "signature-patterns.csv")
 	// Create a rule to validate the output from the following rule.
 	rule := android.NewRuleBuilder(pctx, ctx)
@@ -959,6 +961,7 @@
 		FlagWithInput("--flags ", flagsPath).
 		FlagForEachArg("--split-package ", quotedSplitPackages).
 		FlagForEachArg("--package-prefix ", packagePrefixes).
+		FlagForEachArg("--single-package ", singlePackages).
 		FlagWithOutput("--output ", patternsFile)
 	rule.Build("hiddenAPISignaturePatterns", "hidden API signature patterns")
 
diff --git a/scripts/hiddenapi/signature_patterns.py b/scripts/hiddenapi/signature_patterns.py
index 1abdef1..5a82be7 100755
--- a/scripts/hiddenapi/signature_patterns.py
+++ b/scripts/hiddenapi/signature_patterns.py
@@ -60,7 +60,22 @@
     return False
 
 
-def validate_package_prefixes(split_packages, package_prefixes):
+def validate_package_is_not_matched_by_package_prefix(package_type, pkg,
+                                                      package_prefixes):
+    package_prefix = matched_by_package_prefix_pattern(package_prefixes, pkg)
+    if package_prefix:
+        # A package prefix matches the package.
+        package_for_output = slash_package_to_dot_package(pkg)
+        package_prefix_for_output = slash_package_to_dot_package(package_prefix)
+        return [
+            f'{package_type} {package_for_output} is matched by '
+            f'package prefix {package_prefix_for_output}'
+        ]
+    return []
+
+
+def validate_package_prefixes(split_packages, single_packages,
+                              package_prefixes):
     # If there are no package prefixes then there is no possible conflict
     # between them and the split packages.
     if len(package_prefixes) == 0:
@@ -79,17 +94,16 @@
                 f'{package_prefixes_for_output}\n'
                 '    add split_packages:[] to fix')
         else:
-            package_prefix = matched_by_package_prefix_pattern(
-                package_prefixes, split_package)
-            if package_prefix:
-                # A package prefix matches a split package.
-                split_package_for_output = slash_package_to_dot_package(
-                    split_package)
-                package_prefix_for_output = slash_package_to_dot_package(
-                    package_prefix)
-                errors.append(
-                    f'split package {split_package_for_output} is matched by '
-                    f'package prefix {package_prefix_for_output}')
+            errs = validate_package_is_not_matched_by_package_prefix(
+                'split package', split_package, package_prefixes)
+            errors.extend(errs)
+
+    # Check to make sure that the single packages and package prefixes do not
+    # overlap.
+    for single_package in single_packages:
+        errs = validate_package_is_not_matched_by_package_prefix(
+            'single package', single_package, package_prefixes)
+        errors.extend(errs)
     return errors
 
 
@@ -102,21 +116,40 @@
     return errors
 
 
+def validate_single_packages(split_packages, single_packages):
+    overlaps = []
+    for single_package in single_packages:
+        if single_package in split_packages:
+            overlaps.append(single_package)
+    if overlaps:
+        indented = ''.join([f'\n    {o}' for o in overlaps])
+        return [
+            f'single_packages and split_packages overlap, please ensure the '
+            f'following packages are only present in one:{indented}'
+        ]
+    return []
+
+
 def produce_patterns_from_file(file,
                                split_packages=None,
+                               single_packages=None,
                                package_prefixes=None):
     with open(file, 'r', encoding='utf8') as f:
-        return produce_patterns_from_stream(f, split_packages, package_prefixes)
+        return produce_patterns_from_stream(f, split_packages, single_packages,
+                                            package_prefixes)
 
 
 def produce_patterns_from_stream(stream,
                                  split_packages=None,
+                                 single_packages=None,
                                  package_prefixes=None):
     split_packages = set(split_packages or [])
+    single_packages = set(single_packages or [])
     package_prefixes = list(package_prefixes or [])
     # Read in all the signatures into a list and remove any unnecessary class
     # and member names.
     patterns = set()
+    unmatched_packages = set()
     for row in dict_reader(stream):
         signature = row['signature']
         text = signature.removeprefix('L')
@@ -138,11 +171,31 @@
             # Remove inner class names.
             pieces = qualified_class_name.split('$', maxsplit=1)
             pattern = pieces[0]
-        else:
+            patterns.add(pattern)
+        elif pkg in single_packages:
             # Add a * to ensure that the pattern matches the classes in that
             # package.
             pattern = pkg + '/*'
-        patterns.add(pattern)
+            patterns.add(pattern)
+        else:
+            unmatched_packages.add(pkg)
+
+    # Remove any unmatched packages that would be matched by a package prefix
+    # pattern.
+    unmatched_packages = [
+        p for p in unmatched_packages
+        if not matched_by_package_prefix_pattern(package_prefixes, p)
+    ]
+    errors = []
+    if unmatched_packages:
+        unmatched_packages.sort()
+        indented = ''.join([
+            f'\n    {slash_package_to_dot_package(p)}'
+            for p in unmatched_packages
+        ])
+        errors.append('The following packages were unexpected, please add them '
+                      'to one of the hidden_api properties, split_packages, '
+                      f'single_packages or package_prefixes:{indented}')
 
     # Remove any patterns that would be matched by a package prefix pattern.
     patterns = [
@@ -155,7 +208,13 @@
     patterns = patterns + [f'{p}/**' for p in package_prefixes]
     # Sort the patterns.
     patterns.sort()
-    return patterns
+    return patterns, errors
+
+
+def print_and_exit(errors):
+    for error in errors:
+        print(error)
+    sys.exit(1)
 
 
 def main(args):
@@ -175,26 +234,41 @@
         '--package-prefix',
         action='append',
         help='A package prefix unique to this set of flags')
+    args_parser.add_argument(
+        '--single-package',
+        action='append',
+        help='A single package unique to this set of flags')
     args_parser.add_argument('--output', help='Generated signature prefixes')
     args = args_parser.parse_args(args)
 
     split_packages = set(
         dot_packages_to_slash_packages(args.split_package or []))
     errors = validate_split_packages(split_packages)
+    if errors:
+        print_and_exit(errors)
+
+    single_packages = list(
+        dot_packages_to_slash_packages(args.single_package or []))
+
+    errors = validate_single_packages(split_packages, single_packages)
+    if errors:
+        print_and_exit(errors)
 
     package_prefixes = dot_packages_to_slash_packages(args.package_prefix or [])
 
-    if not errors:
-        errors = validate_package_prefixes(split_packages, package_prefixes)
+    errors = validate_package_prefixes(split_packages, single_packages,
+                                       package_prefixes)
+    if errors:
+        print_and_exit(errors)
+
+    patterns = []
+    # Read in all the patterns into a list.
+    patterns, errors = produce_patterns_from_file(args.flags, split_packages,
+                                                  single_packages,
+                                                  package_prefixes)
 
     if errors:
-        for error in errors:
-            print(error)
-        sys.exit(1)
-
-    # Read in all the patterns into a list.
-    patterns = produce_patterns_from_file(args.flags, split_packages,
-                                          package_prefixes)
+        print_and_exit(errors)
 
     # Write out all the patterns.
     with open(args.output, 'w', encoding='utf8') as outputFile:
diff --git a/scripts/hiddenapi/signature_patterns_test.py b/scripts/hiddenapi/signature_patterns_test.py
index 5c5635c..90b3d0b 100755
--- a/scripts/hiddenapi/signature_patterns_test.py
+++ b/scripts/hiddenapi/signature_patterns_test.py
@@ -32,22 +32,37 @@
     @staticmethod
     def produce_patterns_from_string(csv_text,
                                      split_packages=None,
+                                     single_packages=None,
                                      package_prefixes=None):
         with io.StringIO(csv_text) as f:
             return signature_patterns.produce_patterns_from_stream(
-                f, split_packages, package_prefixes)
+                f, split_packages, single_packages, package_prefixes)
+
+    def test_generate_unmatched(self):
+        _, errors = self.produce_patterns_from_string(
+            TestGeneratedPatterns.csv_flags)
+        self.assertEqual([
+            'The following packages were unexpected, please add them to one of '
+            'the hidden_api properties, split_packages, single_packages or '
+            'package_prefixes:\n'
+            '    java.lang'
+        ], errors)
 
     def test_generate_default(self):
-        patterns = self.produce_patterns_from_string(
-            TestGeneratedPatterns.csv_flags)
+        patterns, errors = self.produce_patterns_from_string(
+            TestGeneratedPatterns.csv_flags, single_packages=['java/lang'])
+        self.assertEqual([], errors)
+
         expected = [
             'java/lang/*',
         ]
         self.assertEqual(expected, patterns)
 
     def test_generate_split_package(self):
-        patterns = self.produce_patterns_from_string(
+        patterns, errors = self.produce_patterns_from_string(
             TestGeneratedPatterns.csv_flags, split_packages={'java/lang'})
+        self.assertEqual([], errors)
+
         expected = [
             'java/lang/Character',
             'java/lang/Object',
@@ -56,8 +71,10 @@
         self.assertEqual(expected, patterns)
 
     def test_generate_split_package_wildcard(self):
-        patterns = self.produce_patterns_from_string(
+        patterns, errors = self.produce_patterns_from_string(
             TestGeneratedPatterns.csv_flags, split_packages={'*'})
+        self.assertEqual([], errors)
+
         expected = [
             'java/lang/Character',
             'java/lang/Object',
@@ -66,16 +83,20 @@
         self.assertEqual(expected, patterns)
 
     def test_generate_package_prefix(self):
-        patterns = self.produce_patterns_from_string(
+        patterns, errors = self.produce_patterns_from_string(
             TestGeneratedPatterns.csv_flags, package_prefixes={'java/lang'})
+        self.assertEqual([], errors)
+
         expected = [
             'java/lang/**',
         ]
         self.assertEqual(expected, patterns)
 
     def test_generate_package_prefix_top_package(self):
-        patterns = self.produce_patterns_from_string(
+        patterns, errors = self.produce_patterns_from_string(
             TestGeneratedPatterns.csv_flags, package_prefixes={'java'})
+        self.assertEqual([], errors)
+
         expected = [
             'java/**',
         ]
@@ -92,21 +113,38 @@
 
     def test_split_package_wildcard_conflicts_with_package_prefixes(self):
         errors = signature_patterns.validate_package_prefixes(
-            {'*'}, package_prefixes={'java'})
+            {'*'}, [], package_prefixes={'java'})
         expected = [
             "split package '*' conflicts with all package prefixes java\n"
             '    add split_packages:[] to fix',
         ]
         self.assertEqual(expected, errors)
 
-    def test_split_package_conflict(self):
+    def test_split_package_conflicts_with_package_prefixes(self):
         errors = signature_patterns.validate_package_prefixes(
-            {'java/split'}, package_prefixes={'java'})
+            {'java/split'}, [], package_prefixes={'java'})
         expected = [
             'split package java.split is matched by package prefix java',
         ]
         self.assertEqual(expected, errors)
 
+    def test_single_package_conflicts_with_package_prefixes(self):
+        errors = signature_patterns.validate_package_prefixes(
+            {}, ['java/single'], package_prefixes={'java'})
+        expected = [
+            'single package java.single is matched by package prefix java',
+        ]
+        self.assertEqual(expected, errors)
+
+    def test_single_package_conflicts_with_split_packages(self):
+        errors = signature_patterns.validate_single_packages({'java/pkg'},
+                                                             ['java/pkg'])
+        expected = [
+            'single_packages and split_packages overlap, please ensure the '
+            'following packages are only present in one:\n    java/pkg'
+        ]
+        self.assertEqual(expected, errors)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)
diff --git a/ui/build/config.go b/ui/build/config.go
index 01fe8fa..dd5bd0c 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -187,7 +187,7 @@
 	}
 
 	if err := fetchEnvConfig(ctx, config, bc); err != nil {
-		fmt.Fprintf(os.Stderr, "Failed to fetch config file: %v", err)
+		fmt.Fprintf(os.Stderr, "Failed to fetch config file: %v\n", err)
 	}
 
 	configDirs := []string{
@@ -1191,7 +1191,12 @@
 }
 
 func (c *configImpl) rbeAuth() (string, string) {
-	credFlags := []string{"use_application_default_credentials", "use_gce_credentials", "credential_file"}
+	credFlags := []string{
+		"use_application_default_credentials",
+		"use_gce_credentials",
+		"credential_file",
+		"use_google_prod_creds",
+	}
 	for _, cf := range credFlags {
 		for _, f := range []string{"RBE_" + cf, "FLAG_" + cf} {
 			if v, ok := c.environ.Get(f); ok {