Update Github CI, docker setup and documentation to run on Ubuntu 24.04 with clang-20 and gcc-14 (#4940)

### What:
Update Github CI, docker setup and documentation to run on Ubuntu 24.04
with clang-20 and gcc-14

### Why:
Since stellar-core packages would be produced for Ubuntu 22.04 (jammy)
and 24.04 (noble) with clang-20 moving forward, we would like to switch
our Github CI to run on the new leading OS version of Ubuntu.

- Update Github actions runner to build with clang-20
- Update docker setup script and docs
- Drop support for Ubuntu 20.04 focal
- Update documentation
- Switch to corresponding gcc/g++ v14. Noble comes with gcc/g++ version
14 while jammy comes with 12. We could get gcc/g++ 13 on Jammy with PPA
dependency. Which version should we recommend in our documentation?
Currently, I have set Github CI to run gcc/g++ v14 since we run on GHA
runner on Ubuntu 24.04.
- Run clang-format-20. Bunch of files have format changes due to this.
Refer to [clang-format20 style
options](https://releases.llvm.org/20.1.0/tools/clang/docs/ClangFormatStyleOptions.html)

Author: anupsdf

.devcontainer/Dockerfile

@@ -2,7 +2,7 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License. See https://go.microsoft.com/fwlink/?linkid=2090316 for license information.
 #-------------------------------------------------------------------------------------------------------------
-FROM ubuntu:focal
+FROM ubuntu:noble
 
 # Avoid warnings by switching to noninteractive
 ENV DEBIAN_FRONTEND=noninteractive
@@ -60,18 +60,18 @@ RUN apt-get update \
 RUN apt-get -y install git build-essential pkg-config autoconf automake libtool bison flex sed perl libpq-dev parallel libunwind-dev curl
 
 # Update compiler tools
-RUN apt-get -y install libstdc++-10-dev clang-format-12 ccache
+RUN apt-get -y install libstdc++-14-dev clang-format-20 ccache
 
 # gcc
-RUN apt-get -y install cpp-10 gcc-10 g++-10
+RUN apt-get -y install cpp-14 gcc-14 g++-14
 # clang
-RUN apt-get -y install clang-12 llvm-12
+RUN apt-get -y install clang-20 llvm-20
 # rust
 ENV PATH "/root/.cargo/bin:$PATH"
 
 # clang by default
-ENV CC=clang-12
-ENV CXX=clang++-12
+ENV CC=clang-20
+ENV CXX=clang++-20
 
 # Install postgresql to enable tests under make check
 RUN apt-get -y install postgresql

.devcontainer/README.md

@@ -1,7 +1,7 @@
-# Ubuntu 20.04 Remote Dev Container Instructions
+# Ubuntu 24.04 Remote Dev Container Instructions
 
 ## Who's interested in this and why?
-* For those developers who'd like to validate their changes on Ubuntu 20.04, we provide a sandboxed development environment using the 'Remote Development Container' features of Microsoft's Visual Studio Code.
+* For those developers who'd like to validate their changes on Ubuntu 24.04, we provide a sandboxed development environment using the 'Remote Development Container' features of Microsoft's Visual Studio Code.
 * This feature pre-configures a dev environment with all the tools you'll need to build stellar-core
 
 

.github/workflows/build.yml

@@ -19,21 +19,21 @@ jobs:
   complete:
     if: always()
     needs: [fmt, cargo-deny, rust-check-git-rev-deps, build]
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
     - if: contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled')
       run: exit 1
 
   fmt:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
     - uses: actions/checkout@v4
     - run: rustup component add rustfmt
     - run: rustup update
     - run: cargo fmt --all --check
 
   cargo-deny:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     strategy:
       matrix:
         checks:
@@ -51,13 +51,13 @@ jobs:
         arguments:
 
   rust-check-git-rev-deps:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
     - uses: actions/checkout@v4
     - uses: stellar/actions/rust-check-git-rev-deps@main
 
   build:
-    runs-on: ubuntu-jammy-16-cores-amd64
+    runs-on: ubuntu-24.04
     env:
       CACHED_PATHS: |
         ~/.ccache
@@ -68,6 +68,7 @@ jobs:
       matrix:
         toolchain: [ "gcc", "clang"]
         protocol: ["current", "next"]
+        scenario: ["", "--check-test-tx-meta"]
     steps:
       - name: Fix kernel mmap rnd bits
         # Asan in llvm provided in ubuntu 22.04 is incompatible with
@@ -115,11 +116,11 @@ jobs:
       - name: install tool chain
         if: steps.cache.outputs.cache-hit != 'true'
         run: |
-          sudo apt-get -y install libstdc++-10-dev clang-format-12 ccache lldb
+          sudo apt-get -y install libstdc++-14-dev clang-format-20 ccache lldb
           if test "${{ matrix.toolchain }}" = "gcc" ; then
-            sudo apt-get -y install cpp-10 gcc-10 g++-10
+            sudo apt-get -y install cpp-14 gcc-14 g++-14
           else
-            sudo apt-get -y install clang-12 llvm-12
+            sudo apt-get -y install clang-20 llvm-20 libc++-20-dev libc++abi-20-dev
           fi
       - name: install rustup components
         if: steps.cache.outputs.cache-hit != 'true'
@@ -144,8 +145,7 @@ jobs:
             export CXX='clang++'
           fi
           echo Build with $CC and $CXX
-          echo "Running first scenario"
-          ./ci-build.sh --use-temp-db --protocol ${{ matrix.protocol }}
+          ./ci-build.sh --use-temp-db --protocol ${{ matrix.protocol }} ${{ matrix.scenario }}
 
       # We only _save_ to the cache when we had a cache miss and are running on master.
       - name: Save cache after first build
@@ -155,15 +155,3 @@ jobs:
           path: ${{ env.CACHED_PATHS }}
           key: ${{ steps.cache.outputs.cache-primary-key }}
 
-      - name: Build for check-test-tx-meta scenario
-        if: steps.cache.outputs.cache-hit != 'true'
-        run: |
-          if test "${{ matrix.toolchain }}" = "gcc" ; then
-            export CC='gcc'
-            export CXX='g++'
-          else
-            export CC='clang'
-            export CXX='clang++'
-          fi
-          echo "Running second scenario with --check-test-tx-meta flag"
-          ./ci-build.sh --use-temp-db --protocol ${{ matrix.protocol }} --check-test-tx-meta