Formally ban absl::optional.

It has been superseded by std::optional.

(Also removes some PRESUBMITs against StringPiece while I'm touching
that block, since that's gone too.)

Bug: 40288126
Change-Id: I8941f1bb75652a4bbb50e95026ea9b6d0ea5ecda
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5805666
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Owners-Override: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1345168}

DEPS

@@ -5036,6 +5036,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

PRESUBMIT.py

@@ -1010,6 +1010,14 @@ _BANNED_CPP_FUNCTIONS: Sequence[BanRule] = (
         True,
         [_THIRD_PARTY_EXCEPT_BLINK],  # Not an error in third_party folders.
     ),
+    BanRule(
+        pattern=
+        r'/\babsl::(optional|nullopt|make_optional)\b',
+        explanation=('absl::optional is banned. Use std::optional instead.', ),
+        treat_as_error=True,
+        excluded_paths=[
+            _THIRD_PARTY_EXCEPT_BLINK,
+        ]),
     BanRule(
         r'/(\babsl::Span\b|#include <span>|\bstd::span\b)',
         (
@@ -1981,27 +1989,6 @@ _BANNED_CPP_FUNCTIONS: Sequence[BanRule] = (
             '^chrome/browser/about_flags.cc',
             '^chrome/browser/web_applications/isolated_web_apps/isolated_web_app_features.cc',
         )),
-    BanRule(
-        pattern=
-        r'/\babsl::(optional|nullopt|make_optional|in_place|in_place_t)\b',
-        explanation=('Don\'t use `absl::optional`. Use `std::optional`.', ),
-        # TODO(b/40288126): Enforce after completing the rewrite.
-        treat_as_error=False,
-        excluded_paths=[
-            _THIRD_PARTY_EXCEPT_BLINK,
-        ]),
-    BanRule(
-        pattern=r'(base::)?\bStringPiece\b',
-        explanation=(
-            'Don\'t use `base::StringPiece`. Use `std::string_view`.', ),
-        treat_as_error=False,
-    ),
-    BanRule(
-        pattern=r'(base::)?\bStringPiece16\b',
-        explanation=(
-            'Don\'t use `base::StringPiece16`. Use `std::u16string_view`.', ),
-        treat_as_error=False,
-    ),
     BanRule(
         pattern='/(CUIAutomation|AccessibleObjectFromWindow)',
         explanation=

ash/assistant/ui/DEPS

@@ -48,6 +48,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

ash/constants/DEPS

@@ -29,6 +29,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chrome/installer/setup/install.cc

@@ -348,9 +348,7 @@ bool CreateVisualElementsManifest(const base::FilePath& src_path,
 
 #if BUILDFLAG(GOOGLE_CHROME_BRANDING)
 // Returns a CommandLine to run if os_update_handler.exe should be run,
-// i.e.. a Windows update has been detected, absl::nullopt otherwise.
-// Use the Windows version update string set by Omaha on the command line
-// as the version update string to pass to os_update_handler.exe.
+// i.e. a Windows update has been detected; null otherwise.
 std::optional<base::CommandLine> GetOsUpdateHandlerCommand(
     const base::FilePath& target_path,
     const std::wstring& installed_version,
@@ -359,6 +357,8 @@ std::optional<base::CommandLine> GetOsUpdateHandlerCommand(
   if (args.size() != 1) {
     return std::nullopt;
   }
+  // Use the Windows version update string set by Omaha on the command line
+  // as the version update string to pass to os_update_handler.exe.
   base::CommandLine os_update_handler_cmd(
       target_path.Append(installed_version).Append(kOsUpdateHandlerExe));
   InstallUtil::AppendModeAndChannelSwitches(&os_update_handler_cmd);

chromeos/ash/components/attestation/DEPS

@@ -31,6 +31,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/ash/components/audio/DEPS

@@ -39,5 +39,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

chromeos/ash/components/cryptohome/DEPS

@@ -32,6 +32,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/ash/components/dbus/DEPS

@@ -42,5 +42,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

chromeos/ash/components/login/auth/DEPS

@@ -46,5 +46,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

chromeos/ash/components/login/integrity/DEPS

@@ -33,5 +33,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

chromeos/ash/components/login/session/DEPS

@@ -30,6 +30,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/ash/components/network/DEPS

@@ -59,6 +59,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/ash/components/tpm/DEPS

@@ -30,6 +30,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/ash/services/recording/DEPS

@@ -40,6 +40,7 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]
 

chromeos/components/onc/DEPS

@@ -31,5 +31,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

chromeos/dbus/DEPS

@@ -35,5 +35,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]

components/cronet/tools/generators/cronet_c_generator.py

@@ -543,7 +543,7 @@ class Generator(generator.Generator):
 
   def _GetCppWrapperType(self, kind, add_same_module_namespaces=False):
     def _AddOptional(type_name):
-      return "absl::optional<%s>" % type_name
+      return "std::optional<%s>" % type_name
 
     if self._IsTypemappedKind(kind):
       type_name = self._GetNativeTypeName(kind)

sandbox/linux/DEPS

@@ -22,5 +22,4 @@ include_rules = [
   "+sandbox/sandbox_export.h",
   # Everyone can use tests/
   "+sandbox/linux/tests",
-  '+third_party/abseil-cpp/absl/types/optional.h',
 ]

styleguide/c++/c++-features.md

@@ -1753,7 +1753,8 @@ Banned since workaround for lack of RTTI
 absl::bind_front
 ```
 
-**Description:** Binds the first N arguments of an invocable object and stores them by value.
+**Description:** Binds the first N arguments of an invocable object and stores
+them by value.
 
 **Documentation:**
 *   [bind_front.h](https://source.chromium.org/chromium/chromium/src/+/main:third_party/abseil-cpp/absl/functional/bind_front.h)
@@ -1859,6 +1860,23 @@ invocable type.
 [Discussion thread](https://groups.google.com/a/chromium.org/g/cxx/c/JVN4E4IIYA0)
 ***
 
+### Optional <sup>[banned]</sup>
+
+```c++
+absl::optional<int> Func(bool b) {
+  return b ? absl::make_optional(1) : abl::nullopt;
+}
+```
+
+**Description:** Early adaptation of C++17 `std::optional`.
+
+**Documentation:** [std::optional](https://en.cppreference.com/w/cpp/utility/optional)
+
+**Notes:**
+*** promo
+Superseded by `std::optional`. Use `std::optional` instead.
+***
+
 ### Random <sup>[banned]</sup>
 
 ```c++

ui/events/keycodes/DEPS

@@ -32,5 +32,6 @@ include_rules = [
   '-third_party/abseil-cpp/absl/synchronization',
   '-third_party/abseil-cpp/absl/time',
   '-third_party/abseil-cpp/absl/types/any.h',
+  '-third_party/abseil-cpp/absl/types/optional.h',
   '-third_party/abseil-cpp/absl/types/span.h',
 ]