AK: Add an OptionalBase helper, and allow specializing Optional with dedicated empty values #25894

Hendiadyoin1 · 2025-04-16T22:34:42Z

CC: @LucasChollet
CC: @nico to cross check if apple-clang really supports this or if wikipedia is weird
CC: Whoever knows if the CI changes are correct

Based on LadybirdBrowser/ladybird#2032
But still need to cherry-pick and adapt the String changes

Depends on #25891 for the GCC version bump

Hendiadyoin1 · 2025-04-16T22:38:11Z

Ah wait the CI containers dont ship gcc-14?

spholz · 2025-04-18T19:28:07Z

Meta/build-image-extlinux.sh

@@ -4,6 +4,7 @@ set -e

 script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)

+# shellcheck source=/dev/null


IIRC these don't fail in CI, but only in the pre-commit check, because we only pass the changed scripts to shellcheck, which doesn't include shell_include.sh.

So most (if not all) # shellcheck source=/dev/null we already have in master might be unnecessary.

Well it failed CI without the one in this exact file you point out....

Weird, I have no idea why it fails here then.
I'm 99% sure that the build-image-raspberry-pi.sh one only failed in the pre-commit hook.

I wonder if we should pass -x in lint-shell-scripts.sh then. That should make these comments unnecessary.
That flag seems to do the same thing as setting external-sources=true in .shellcheckrc.

The man page says that option can be safely enabled for normal development: https://github.com/koalaman/shellcheck/blob/master/shellcheck.1.md#directives

You don't need to do that in this PR though.

Hendiadyoin1 · 2025-04-18T19:30:30Z

Whoops, this breaks jakt builds

Hendiadyoin1 · 2025-04-18T19:41:11Z

Also Something in the NNRP code still seems off, will continue to test

AK/Optional.h

stale · 2025-05-10T22:03:17Z

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

AK/StringBase.h

AK/NonnullOwnPtr.h

AK/Optional.h

AK/MACAddress.h

LucasChollet · 2025-05-17T16:06:11Z

AK/Optional.h

+        else if constexpr (IsCallableWithArguments<decltype(Traits<T>::special_optional_empty_value), T>)
+            return Traits<T>::special_optional_empty_value();


Is this branch ever used? We seem to always define special_optional_empty_value(Badge<Optional<T>>)

Yes, not using this version yet, as all special values are currently "illegal" values, so all APIs are currently Badged
left it in as it might come usefull

Note the immediate value branch is also currently unused

left it in as it might come usefull

I think that we usually don't add unused code. So we should probably remove these two branches.

alimpfard · 2025-05-28T23:21:55Z

Jakt stuff should be good on master, just drop the last commit and rebase.

stale · 2025-06-20T19:04:52Z

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions!

This also makes the monadic helpers a bit stricter with their value types, hence the drive-by changes.

Not sure why it wasn't in there in the first place...

This will be needed in the next commit, as Optional then starts to call into Traits, and the affected Types initialize their own Optional so a Traits specialization needs to already be declared.

The new Optional implementation is chosen when a `Traits<T>::special_optional_empty_value` exists, this can be an immediate value or a function optionally taking a Badge<Optional<T>>. You can also define a custom specialization of `Traits<T>::optional_has_value`, as otherwise the default goes through the `==`/`!=` operators, which may not be defined.

Akin to LadybirdBrowser/ladybird@2457118

spholz

I can't really comment on the Optional changes. That is too much C++ metapogramming for me. But here are some more general comments from me.

spholz · 2025-06-22T10:34:25Z

.github/actions/setup/action.yml


        sudo add-apt-repository ppa:ubuntu-toolchain-r/test

        sudo apt-get update
        sudo apt-get install ccache clang-18 clang++-18 clang-format-18 lld-18 gcc-13 g++-13 libstdc++-13-dev ninja-build unzip qt6-base-dev qt6-tools-dev-tools libqt6svg6-dev qt6-multimedia-dev libgl1-mesa-dev libpulse-dev libssl-dev libegl1-mesa-dev libclang-18-dev

-        sudo apt-get remove clang-{13,14,15} clang++-{13,14,15} libclang-{13,14,15}-dev llvm-{13,14,15}
+        sudo apt-get remove clang-{14,15} clang++-{14,15} libclang-{14,15}-dev llvm-{14,15}


Should we remove other clang versions that are now in the repos as well?
clang-14 to clang-18 seem to be in the repos.

I think that also means we don't really need the ubuntu-toolchain PPA or LLVM toolchain repo?

spholz · 2025-06-22T10:37:09Z

.github/actions/setup/action.yml

        # cmake libgmp-dev npm shellcheck
        # Packages below aren't.

        set -e

        wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-        sudo add-apt-repository 'deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-18 main'
+        sudo add-apt-repository 'deb http://apt.llvm.org/noble/ llvm-toolchain-noble-18 main'

        sudo add-apt-repository ppa:ubuntu-toolchain-r/test

        sudo apt-get update
        sudo apt-get install ccache clang-18 clang++-18 clang-format-18 lld-18 gcc-13 g++-13 libstdc++-13-dev ninja-build unzip qt6-base-dev qt6-tools-dev-tools libqt6svg6-dev qt6-multimedia-dev libgl1-mesa-dev libpulse-dev libssl-dev libegl1-mesa-dev libclang-18-dev


Ninja, unzip, gcc-{13,14}, g++-{13,14}, libssl-dev, and all llvm stuff seems to be preinstalled now:
https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md

spholz · 2025-06-22T10:40:23Z

.github/actions/setup/action.yml

@@ -29,15 +29,15 @@ runs:
        sudo add-apt-repository ppa:ubuntu-toolchain-r/test

        sudo apt-get update
-        sudo apt-get install ccache clang-18 clang++-18 clang-format-18 lld-18 gcc-13 g++-13 libstdc++-13-dev ninja-build unzip qt6-base-dev qt6-tools-dev-tools libqt6svg6-dev qt6-multimedia-dev libgl1-mesa-dev libpulse-dev libssl-dev libegl1-mesa-dev libclang-18-dev
+        sudo apt-get install ccache clang-18 clang++-18 clang-format-18 lld-18 gcc-14 g++-14 libstdc++-13-dev ninja-build unzip qt6-base-dev qt6-tools-dev-tools libqt6svg6-dev qt6-multimedia-dev libgl1-mesa-dev libpulse-dev libssl-dev libegl1-mesa-dev libclang-18-dev


I think you want libstdc++-14 here if we want to keep installing gcc packages explicitly.

spholz · 2025-06-22T10:40:41Z

.github/actions/setup/action.yml

@@ -69,7 +69,7 @@ runs:

        sudo apt-get update
        sudo apt-get remove clang-{14,15} clang++-{14,15} libclang-{14,15}-dev llvm-{14,15}
-        sudo apt-get install clang-format-18 ccache e2fsprogs gcc-13 g++-13 libstdc++-13-dev libmpfr-dev libmpc-dev ninja-build optipng qemu-utils qemu-system-i386 unzip generate-ninja libegl1-mesa-dev
+        sudo apt-get install clang-format-18 ccache e2fsprogs gcc-14 g++-14 libstdc++-13-dev libmpfr-dev libmpc-dev ninja-build optipng qemu-utils qemu-system-i386 unzip generate-ninja libegl1-mesa-dev


spholz · 2025-06-22T10:41:59Z

Documentation/BuildInstructions.md

+#### GCC 14 or Clang 18+

-A host compiler that supports C++23 features is required for building host tools, the newer the better. Tested versions include gcc-13 and Clang 17 through 19.
+A host compiler that supports C++23 features is required for building host tools, the newer the better. Tested versions include gcc-14 and Clang 18 through 19.


GCC 15 and Clang 20 as well.

spholz · 2025-06-22T10:42:58Z

Meta/find_compiler.sh

+    find_newest_compiler clang clang-18 /opt/homebrew/opt/llvm/bin/clang
    if is_supported_compiler "$HOST_COMPILER"; then
        export CC="${HOST_COMPILER}"
        export CXX="${HOST_COMPILER/clang/clang++}"
        return
    fi

-    find_newest_compiler egcc gcc gcc-13 gcc-14 /usr/local/bin/gcc-{13,14} /opt/homebrew/bin/gcc-{13,14}
+    find_newest_compiler egcc gcc gcc-14 /usr/local/bin/gcc-14 /opt/homebrew/bin/gcc-14


What about Clang 19/20 and GCC 15?

spholz · 2025-06-22T10:46:52Z

Documentation/SelfHostedRunners.md

@@ -25,13 +25,13 @@ sudo add-apt-repository ppa:canonical-server/server-backports
 wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
 sudo add-apt-repository 'deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-16 main'
 apt update
-apt install git build-essential make cmake clang-format-16 gcc-13 g++-13 libstdc++-13-dev libgmp-dev ccache libmpfr-dev libmpc-dev ninja-build e2fsprogs qemu-utils qemu-system-i386 wabt
+apt install git build-essential make cmake clang-format-16 gcc-14 g++-14 libstdc++-13-dev libgmp-dev ccache libmpfr-dev libmpc-dev ninja-build e2fsprogs qemu-utils qemu-system-i386 wabt


Also this libstdc++-13-dev here.

spholz · 2025-06-22T10:47:12Z

Documentation/SelfHostedRunners.md

@@ -25,13 +25,13 @@ sudo add-apt-repository ppa:canonical-server/server-backports
 wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
 sudo add-apt-repository 'deb http://apt.llvm.org/jammy/ llvm-toolchain-jammy-16 main'
 apt update
-apt install git build-essential make cmake clang-format-16 gcc-13 g++-13 libstdc++-13-dev libgmp-dev ccache libmpfr-dev libmpc-dev ninja-build e2fsprogs qemu-utils qemu-system-i386 wabt
+apt install git build-essential make cmake clang-format-16 gcc-14 g++-14 libstdc++-13-dev libgmp-dev ccache libmpfr-dev libmpc-dev ninja-build e2fsprogs qemu-utils qemu-system-i386 wabt
 ```

 ### Force usage of GCC 13


spholz · 2025-06-22T10:50:51Z

.github/actions/setup/action.yml

You also need to update

"brew install gcc@13" in BuildInstructionsMacOS.md

"a suitable C++ compiler (g++ >= 13, clang >= 14, Apple Clang >= 14.3) via the CMAKE_CXX_COMPILER and" in BuildInstructionsLadybird.md

"Toolchain/Local/x86_64/x86_64-pc-serenity/include/c++/13.1.0" in QtCreatorConfiguration.md

"If you have Xcode version 14.2 or older, also install a newer host compiler from homebrew. Xcode 14.3 is known to work." in BuildInstructionsMacOS.md

"Xcode 14 versions before 14.3 might crash while building ladybird. Xcode 14.3 or clang from homebrew may be required to successfully build ladybird." in BuildInstructionsLadybird.md

spholz · 2025-06-22T10:54:11Z

AK/MACAddress.h

+class MACAddress;
+template<>
+struct Traits<MACAddress>;


These forward declarations seem unrelated.
I think you meant to add them in the next commit?

Hendiadyoin1 force-pushed the OptionalBase branch 3 times, most recently from 3f18ba3 to 5654981 Compare April 18, 2025 18:32

Hendiadyoin1 marked this pull request as ready for review April 18, 2025 18:32

Hendiadyoin1 requested a review from alimpfard as a code owner April 18, 2025 18:32

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Hendiadyoin1 force-pushed the OptionalBase branch from 5654981 to 13f16f2 Compare April 18, 2025 19:22

spholz reviewed Apr 18, 2025

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Hendiadyoin1 force-pushed the OptionalBase branch from fd5a34f to 4d8dcfe Compare April 19, 2025 16:08

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Hendiadyoin1 force-pushed the OptionalBase branch from 4d8dcfe to 8b91b67 Compare May 10, 2025 22:24

stale bot removed the stale label May 10, 2025

LucasChollet reviewed May 11, 2025

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Hendiadyoin1 force-pushed the OptionalBase branch 2 times, most recently from 71f4a18 to 068a3ed Compare May 16, 2025 18:18

Hendiadyoin1 mentioned this pull request May 16, 2025

codegen: Use auto&& for value capture in optional chaining/coalescing SerenityOS/jakt#1614

Merged

Hendiadyoin1 force-pushed the OptionalBase branch from 068a3ed to a5d9c77 Compare May 17, 2025 13:12

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Hendiadyoin1 force-pushed the OptionalBase branch from a5d9c77 to 7a240b0 Compare May 17, 2025 16:06

Hendiadyoin1 requested a review from BertalanD as a code owner May 17, 2025 16:15

Hendiadyoin1 force-pushed the OptionalBase branch from ef12c4b to 6c59b6b Compare May 21, 2025 17:38

Hendiadyoin1 force-pushed the OptionalBase branch from 6c59b6b to 1b4acb9 Compare May 30, 2025 15:12

stale bot added the stale label Jun 20, 2025

Hendiadyoin1 added 9 commits June 20, 2025 21:50

Meta: Fix some shellcheck issues

9f41b05

CI: Bump Ubuntu runner to 24.04

cbd3ce7

Meta+CI: Bump minimum compiler versions to support deducing-this

150fc6e

AK: Make Badge constexpr movable

27a06b0

AK: Add an OptionalBase helper to ease specializing Optional<T>

1fce490

This also makes the monadic helpers a bit stricter with their value types, hence the drive-by changes.

AK: Move MACAddress into the AK namespace

985b586

Not sure why it wasn't in there in the first place...

AK: Move some Traits<T> specializations up

be076dd

This will be needed in the next commit, as Optional then starts to call into Traits, and the affected Types initialize their own Optional so a Traits specialization needs to already be declared.

AK: Use a null value for Optional<(Fly)String>s empty value

f297f61

Akin to LadybirdBrowser/ladybird@2457118

Hendiadyoin1 force-pushed the OptionalBase branch from 1b4acb9 to f297f61 Compare June 20, 2025 19:51

stale bot removed the stale label Jun 20, 2025

spholz reviewed Jun 22, 2025

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		@@ -4,6 +4,7 @@ set -e

		script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)

		# shellcheck source=/dev/null

		else if constexpr (IsCallableWithArguments<decltype(Traits<T>::special_optional_empty_value), T>)
		return Traits<T>::special_optional_empty_value();

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AK: Add an OptionalBase helper, and allow specializing Optional with dedicated empty values #25894

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AK: Add an OptionalBase helper, and allow specializing Optional with dedicated empty values #25894

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Hendiadyoin1 commented Apr 16, 2025

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alimpfard commented May 28, 2025

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spholz Apr 18, 2025 •

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