GH-43623: [R] remove libarrow backwards compatibility enforcement

.github/workflows/r.yml

@@ -62,63 +62,6 @@ env:
   DOCKER_VOLUME_PREFIX: ".docker/"
 
 jobs:
-  ubuntu-minimum-cpp-version:
-    name: Check minimum supported Arrow C++ Version (${{ matrix.cpp_version }})
-    runs-on: ubuntu-22.04
-    strategy:
-      matrix:
-        include:
-          - cpp_version: "19.0.1"
-    steps:
-    - name: Checkout Arrow
-      uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4.0.0
-      with:
-        path: src
-        submodules: recursive
-
-    - name: Install Arrow C++ (${{ matrix.cpp_version }})
-      run: |
-        sudo apt update
-        sudo apt install -y -V ca-certificates lsb-release wget
-        wget https://apache.jfrog.io/artifactory/arrow/$(lsb_release --id --short | tr 'A-Z' 'a-z')/apache-arrow-apt-source-latest-$(lsb_release --codename --short).deb
-        sudo apt install -y -V ./apache-arrow-apt-source-latest-$(lsb_release --codename --short).deb
-        sudo apt update
-        # We have to list all packages to avoid version conflicts.
-        sudo apt install -y -V libarrow-dev=${{ matrix.cpp_version }}-1 \
-                               libarrow-acero-dev=${{ matrix.cpp_version }}-1 \
-                               libparquet-dev=${{ matrix.cpp_version }}-1 \
-                               libarrow-dataset-dev=${{ matrix.cpp_version }}-1
-
-    - name: Install checkbashisms
-      run: |
-        sudo apt-get install devscripts
-
-    - uses: r-lib/actions/setup-r@v2
-      with:
-        use-public-rspm: true
-        install-r: false
-
-    - uses: r-lib/actions/setup-r-dependencies@v2
-      with:
-        extra-packages: any::rcmdcheck
-        needs: check
-        working-directory: src/r
-
-    - uses: r-lib/actions/check-r-package@v2
-      with:
-        working-directory: src/r
-      env:
-        LIBARROW_BINARY: "false"
-        LIBARROW_BUILD: "false"
-        ARROW_R_VERBOSE_TEST: "true"
-        ARROW_R_ALLOW_CPP_VERSION_MISMATCH: "true"
-
-    - name: Show install output
-      if: always()
-      run: find src/r/check -name '00install.out*' -exec cat '{}' \; || true
-      shell: bash
-
-
   ubuntu:
     name: AMD64 Ubuntu ${{ matrix.ubuntu }} R ${{ matrix.r }} Force-Tests ${{ matrix.force-tests }}
     runs-on: ubuntu-latest

r/PACKAGING.md

@@ -25,7 +25,7 @@ For a high-level overview of the Arrow release process see the [Apache Arrow Rel
 ## Before the Arrow Release Candidate Is Created
 
 - [ ] [Create a GitHub issue](https://github.com/apache/arrow/issues/new/) entitled `[R] CRAN packaging checklist for version X.Y.Z` and copy this checklist to the issue.
-- [ ] Review deprecated functions to advance their deprecation status, including removing preprocessor directives that no longer apply (search for `ARROW_VERSION_MAJOR` in r/src).
+- [ ] Review deprecated functions to advance their deprecation status.
 - [ ] Evaluate the status of any failing [nightly tests and nightly packaging builds](http://crossbow.voltrondata.com). These checks replicate most of the checks that CRAN runs, so we need them all to be passing or to understand that the failures may (though won't necessarily) result in a rejection from CRAN.
 - [ ] Check [current CRAN check results](https://cran.rstudio.org/web/checks/check_results_arrow.html).
 - [ ] Ensure the contents of the README are accurate and up to date.

r/src/altrep.cpp

@@ -80,13 +80,8 @@ void DeletePointer(std::shared_ptr<T>* ptr) {
 template <typename T>
 using Pointer = cpp11::external_pointer<std::shared_ptr<T>, DeletePointer<T>>;
 
-#if ARROW_VERSION_MAJOR >= 18
 using ChunkResolver = arrow::ChunkResolver;
 using ChunkLocation = arrow::ChunkLocation;
-#else
-using ChunkResolver = arrow::internal::ChunkResolver;
-using ChunkLocation = arrow::internal::ChunkLocation;
-#endif
 
 class ArrowAltrepData {
  public:

r/src/extension-impl.cpp

@@ -100,11 +100,7 @@ std::string RExtensionType::ToString(bool show_metadata) const {
   // In the event of an error (e.g., we are not on the main thread
   // and we are not inside RunWithCapturedR()), just call the default method
   if (!result.ok()) {
-#if ARROW_VERSION_MAJOR >= 16
     return ExtensionType::ToString(show_metadata);
-#else
-    return ExtensionType::ToString();
-#endif
   } else {
     return result.ValueUnsafe();
   }

r/src/filesystem.cpp

@@ -429,11 +429,7 @@ std::shared_ptr<fs::GcsFileSystem> fs___GcsFileSystem__Make(bool anonymous,
   }
 
   auto io_context = MainRThread::GetInstance().CancellableIOContext();
-#if ARROW_VERSION_MAJOR >= 18
   return ValueOrStop(fs::GcsFileSystem::Make(gcs_opts, io_context));
-#else
-  return fs::GcsFileSystem::Make(gcs_opts, io_context);
-#endif
 }
 
 // [[gcs::export]]