Error compiling storage/ducklake_insert.cpp while building ducklake-iceberg

[youattd]

Seeing a repeatable compile error while trying to build duckdb-iceberg. On the surface it looks like a type conflict in the function return value and the type of result allocated using make_uniq. Opened this as a question since it happens when trying to build duckdb-iceberg which pulls in ducklake from a cmake file, and checks out a specific commit hash for ducklake. So not certain there's not a missing include file or it's finding or using a wrong include file.

Behavior seems to be the same whether we checkout duckdb_iceberg/duckdb at main, v1.4.1. recent v1.4.2 tag or let it default to whatever duckdb-iceberg checks out.

$ cd duckdb_iceberg/
$ ls
CMakeLists.txt  data  duckdb  extension-ci-tools  extension_config.cmake  LICENSE  Makefile  README.md  scripts  src  test  vcpkg_installed  vcpkg.json
$ git status
HEAD detached at 5f5cd041

$ cd duckdb
$ git status
HEAD detached at 68d7555f68
nothing to commit, working tree clean

Here's the error:

[ 51%] Building CXX object extension/ducklake/src/storage/CMakeFiles/ducklake_storage.dir/ducklake_inlined_data_reader.cpp.o
[ 51%] Building CXX object extension/ducklake/src/storage/CMakeFiles/ducklake_storage.dir/ducklake_insert.cpp.o
/duckdb_iceberg-1.4.2/build/release/_deps/ducklake_extension_fc-src/src/storage/ducklake_insert.cpp: In static member function 'static duckdb::unique_ptr<duckdb::LogicalOperator> duckdb::DuckLakeInsert::InsertCasts(duckdb::Binder&, duckdb::unique_ptr<duckdb::LogicalOperator>&)':

/duckdb_iceberg-1.4.2/build/release/_deps/ducklake_extension_fc-src/src/storage/ducklake_insert.cpp:670:16: error: could not convert 'result' from 'unique_ptr<duckdb::LogicalProjection,default_delete<duckdb::LogicalProjection>,[...]>' to 'unique_ptr<duckdb::LogicalOperator,default_delete<duckdb::LogicalOperator>,[...]>'
  670 |         return result;
      |                ^~~~~~
      |                |
      |                unique_ptr<duckdb::LogicalProjection,default_delete<duckdb::LogicalProjection>,[...]>
gmake[3]: *** [extension/ducklake/src/storage/CMakeFiles/ducklake_storage.dir/build.make:174: extension/ducklake/src/storage/CMakeFiles/ducklake_storage.dir/ducklake_insert.cpp.o] Error 1
gmake[3]: Leaving directory '/duckdb_iceberg-1.4.2/build/release'
gmake[2]: *** [CMakeFiles/Makefile2:8746: extension/ducklake/src/storage/CMakeFiles/ducklake_storage.dir/all] Error 2
gmake[2]: Leaving directory '/duckdb_iceberg-1.4.2/build/release'
gmake[1]: *** [Makefile:136: all] Error 2
gmake[1]: Leaving directory '/duckdb_iceberg-1.4.2/build/release'
make: *** [extension-ci-tools/makefiles/duckdb_extension.Makefile:161: release] Error 2
error: Bad exit status from /var/tmp/rpm-tmp.Jtmc9d (%build)

here's the function (and file https://github.com/duckdb/ducklake/blob/main/src/storage/ducklake_insert.cpp). The function was added in the September 2025 timeframe according to blame:

// Note template type is LogicalOperator
unique_ptr<LogicalOperator> DuckLakeInsert::InsertCasts(Binder &binder, unique_ptr<LogicalOperator> &plan) {
    vector<unique_ptr<Expression>> cast_expressions;

    auto &types = plan->types;
    auto bindings = plan->GetColumnBindings();

    for (idx_t col_idx = 0; col_idx < types.size(); col_idx++) {
        auto &type = types[col_idx];
        auto &binding = bindings[col_idx];
        auto ref_expr = make_uniq<BoundColumnRefExpression>(type, binding);
        if (DuckLakeTypes::RequiresCast(type)) {
            auto new_type = DuckLakeTypes::GetCastedType(type);
            cast_expressions.push_back(
                BoundCastExpression::AddCastToType(binder.context, std::move(ref_expr), new_type));
        } else {
            cast_expressions.push_back(std::move(ref_expr));
        }
    }

    // Note template type is LogicalProjection
    auto result = make_uniq<LogicalProjection>(binder.GenerateTableIndex(), std::move(cast_expressions));
    result->children.push_back(std::move(plan));

    return result;
}

note the auto result templated type of LogicalProjection and the func's declared return type of templated LogicalOperator. They have the same pattern in other files, but in those the return type matches ptr result type.

It uses a utility function make_uniq (obviously), which uses c++ template type forwarding, so suspected at one point that it may be a newer gcc feature. The compiler used is the default on Alma 9: c++ (GCC) 11.5.0 20240719 (Red Hat 11.5.0-5)

The path to that file (from a sandbox build) is /duckdb_iceberg-1.4.2/build/release/_deps/ducklake_extension_fc-src/src/storage/ducklake_insert.cpp

here's the cmake file w/the embedded hard coded commit hash to pull. this is in the duckdb repo https://github.com/duckdb/duckdb/blob/68d7555f68bd25c1a251ccca2e6338949c33986a/.github/config/extensions/ducklake.cmake

and the make_uniq helper func is declared here https://github.com/duckdb/duckdb/blob/68d7555f68bd25c1a251ccca2e6338949c33986a/src/include/duckdb/common/helper.hpp

Any advice is welcome.

[Tmonster]

Hi,

Thanks for filing this issue. I have not been able to reproduce it yet. Can you answer the following for me?

• Do you see the line -- Load extension 'iceberg' from '/Users/tomebergen/duckdb-iceberg' @ 5f5cd0412 when compiling? And is the hash the same?
• Are you compiling with Vcpkg?
• What architecture are you building on?
• What compiler are you using?

This can help narrow down the issue so I can try and reproduce

In the meantime, you can disable the compiling of Ducklake with DuckDB-Iceberg by removing the following lines from extension_config.cmake

duckdb_extension_load(ducklake
        LOAD_TESTS
        GIT_URL https://github.com/duckdb/ducklake
        GIT_TAG f134ad86f2f6e7cdf4133086c38ecd9c48f1a772
)

[sfc-gh-dyouatt]

This was caused by the default older v11 gcc toolset.

FWIW, Alma 10 uses the 14 gcc toolset by default and it compiles/builds successfully there.

And Alma 9 also works if we use scl to tell it to use the 14 gcc toolset.

Based on that, please close this if you want to.

[youattd]

Hi @Tmonster. Thank you for looking at this.

This is on Alma 9, x86_64, with the default (and older) v11 gcc toolset. ducklake builds successfully with the newer v14 gcc toolset which is the default and Alma 10, and is available on Alma 9, just not the default. Also, yes, using vcpkg.

I think we've resolved this one.

[Tmonster]

Closing as it seems this is resolved. @youattd please reopen if not the case