Compilation failure in clang/LLVM 19 due to incorrect member name base() in graph_traits_HalfedgeDS.h

[tylermorganwall]

Issue Details

I write an R package that links CGAL, and I was recently informed that the package was failing to install with LLVM 19 due to missing member functions.

Here are the installation logs:

/data/gannet/ripley/R/test-clang/RcppCGAL/include/CGAL/boost/graph/iterator.h:219:22: error: no member named 'base' in 'Halfedge_around_source_iterator'
219 | return (! (this->base() == nullptr));
| ~~~~ ^
/data/gannet/ripley/R/test-clang/RcppCGAL/include/CGAL/boost/graph/iterator.h:313:22: error: no member named 'base' in 'Halfedge_around_target_iterator'
313 | return (! (this->base() == nullptr));
| ~~~~ ^
/data/gannet/ripley/R/test-clang/RcppCGAL/include/CGAL/boost/graph/iterator.h:405:22: error: no member named 'base' in 'Halfedge_around_face_iterator'
405 | return (! (this->base() == nullptr));
| ~~~~ ^
3 errors generated.

(Here are the full logs: https://www.stats.ox.ac.uk/pub/bdr/clang19/raybevel.log)

I believe this should be this::base_reference(), as all the other similarly templated classes in the header call that member function.

Example:

cgal/BGL/include/CGAL/boost/graph/iterator.h

Lines 496 to 510 in 29ed736

	Halfedge_around_source_circulator()
	{}
	Halfedge_around_source_circulator(halfedge_descriptor hd, const Graph& g)
	: Halfedge_around_source_circulator::iterator_adaptor_(Halfedge_around_target_circulator<Graph>(opposite(hd,g),g)), opp(g)
	{}
	Halfedge_around_source_circulator(vertex_descriptor vd, const Graph& g)
	: Halfedge_around_source_circulator::iterator_adaptor_(Halfedge_around_target_circulator<Graph>(halfedge(vd,g),g)), opp(g)
	{}
	explicit operator bool() const
	{
	return (! (this->base_reference() == nullptr));
	}

Source Code

The lines causing these errors is located in these locations:

cgal/BGL/include/CGAL/boost/graph/iterator.h

Lines 215 to 219 in 29ed736

	#ifndef DOXYGEN_RUNNING
	explicit operator bool() const
	{
	return (! (this->base() == nullptr));

cgal/BGL/include/CGAL/boost/graph/iterator.h

Lines 311 to 314 in 29ed736

	explicit operator bool() const
	{
	return (! (this->base() == nullptr));
	}

cgal/BGL/include/CGAL/boost/graph/iterator.h

Lines 403 to 406 in 29ed736

	explicit operator bool() const
	{
	return (! (this->base() == nullptr));
	}

Environment

• Clang/LLVM 19.0.0

[lrineau]

Hi, those operator bool should be removed: they are useless, because the types are iterators, and not circulators.

I suggest the following patch:

diff --git a/BGL/include/CGAL/boost/graph/iterator.h b/BGL/include/CGAL/boost/graph/iterator.h
index 54b54c08ecb..cef4a913cad 100644
--- a/BGL/include/CGAL/boost/graph/iterator.h
+++ b/BGL/include/CGAL/boost/graph/iterator.h
@@ -214,11 +214,6 @@ public:
 
 #ifndef DOXYGEN_RUNNING
 
-  explicit operator bool() const
-  {
-    return (! (this->base() == nullptr));
-  }
-
   bool operator==( const Self& i) const {
     CGAL_assertion( anchor == anchor);
     return  ( g == i.g) && ( pos == i.pos) && ( winding == i.winding);
@@ -308,11 +303,6 @@ public:
 
 #ifndef DOXYGEN_RUNNING
 
-  explicit operator bool() const
-  {
-    return (! (this->base() == nullptr));
-  }
-
   bool operator==( const Self& i) const {
     CGAL_assertion( anchor == anchor);
     return  ( g == i.g) && ( pos == i.pos) && ( winding == i.winding);
@@ -400,11 +390,6 @@ public:
   pointer           operator -> ( )       { return &pos; }
   const value_type* operator -> ( ) const { return &pos; }
 
-  explicit operator bool() const
-  {
-    return (! (this->base() == nullptr));
-  }
-
   bool operator==( const Self& i) const {
     CGAL_assertion( anchor == anchor);
     return  ( g == i.g) && ( pos == i.pos) && ( winding == i.winding);

Can you please try it, and let us know?

[tylermorganwall]

I have confirmed the above patch fixes the issue on clang/LLVM 19.0.0.

[tylermorganwall]

Here is the Dockerfile I used to confirm the patch works:

# Use an Ubuntu base image
FROM ubuntu:22.04

# Set environment variables
ENV DEBIAN_FRONTEND=noninteractive

# Install necessary packages
RUN apt-get update && apt-get install -y \
    build-essential \
    cmake \
    git \
    wget \
    lsb-release \
    software-properties-common \
    gnupg \
    libgmp-dev \
    libmpfr-dev \
    libboost-all-dev \
    libeigen3-dev \
    patch

# Install clang/LLVM 19.0.0
RUN wget https://apt.llvm.org/llvm.sh && chmod +x llvm.sh && ./llvm.sh 19

# Set clang/LLVM as default compiler
RUN update-alternatives --install /usr/bin/cc cc /usr/bin/clang-19 100
RUN update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-19 100

# Copy the patch file into the container
COPY cgal_patch.diff /usr/local/src/cgal_patch.diff

# Clone and build CGAL with the patch
RUN git clone https://github.com/CGAL/cgal.git /usr/local/src/cgal && \
    cd /usr/local/src/cgal && \
    git apply /usr/local/src/cgal_patch.diff && \
    mkdir -p build && cd build && \
    cmake -DCMAKE_BUILD_TYPE=Release .. && \
    make && \
    make install && \
    echo "CGAL build and installation completed successfully."

# Verify installation
RUN ls /usr/local/lib && ls /usr/local/include/CGAL

# Clean up
RUN apt-get clean && rm -rf /var/lib/apt/lists/*

# Set up a working directory
WORKDIR /workspace

# Command to keep the container running
CMD ["bash"]

And the test file I compiled:

#include <CGAL/Simple_cartesian.h>
#include <CGAL/Surface_mesh.h>
#include <iostream>

int main() {
    typedef CGAL::Simple_cartesian<double> Kernel;
    typedef CGAL::Surface_mesh<Kernel::Point_3> Mesh;

    Mesh mesh;
    std::cout << "CGAL and clang/LLVM 19.0.0 are set up correctly!" << std::endl;
    return 0;
}

Without the patch, the compilation with clang 19 failed with the error in the initial post. With the patch applied there is no error and the program successfully compiles.