Unknown CMake command "build_static_extension"

[ju-klein]

Dear everybody,
similar to #96, I get the same error message when trying to work with a specific extension ( https://github.com/dais-polymtl/flock ) in VSCode.

Since VSCode relies on LSP as well (I think (n)vim does), I would think that maybe my problem is similar.
I tried to create a compile_commands.json using set(CMAKE_EXPORT_COMPILE_COMMANDS ON) in CMakeLists.txt.

I also get a LARGE compile_commands.json out of it and handed that to VSCode inside c_cpp_properties.json.

Still the same error. Has anyone ( maybe @rob2244) solved this?

If there is anything I can do to help, please lmk!

Behavior:

VSCode tells me: Configure failed. Would you like to attempt to configure with the CMake Debugger? Source: CMake Tools

Expected Behavior:

No error message and I can use the debugger(Edit: I can use GDB).

Steps to reproduce:

Set up flock (remember to put DuckDB INSIDE flock repo) and try to open repository inside VSCode.

Environment (Dockerfile):

# based on this guide: https://docs.docker.com/get-started/docker-concepts/building-images/writing-a-dockerfile/
# and rewritten after reading through https://docs.docker.com/get-started/workshop/
# install -y taken from https://github.com/llvm/llvm-project/issues/81470
# (trixie) used debian trixie because of need for curl > 8.9 as taken from here: https://discourse.cmake.org/t/why-cant-i-find-curl-when-cross-compiling/11041/4
FROM debian:trixie-slim
WORKDIR /duckdb-build-env

# this is the required JSON package for compiling flockMTL. how to use build arguments taken from https://docs.docker.com/build/building/variables/
ENV NLOHMANN_JSON=https://github.com/nlohmann/json.git

# this is googletest, required for compiling flockmtl
ENV GTEST=https://github.com/google/googletest.git

# needed for compiling DuckDB. 
# git is needed to get a proper version of DuckDB instead of v0.0.1
# parallel is useful for testing DuckDB (do we need to cite the github comment for parallel ( https://github.com/catchorg/Catch2/issues/399#issuecomment-672391192 )here?)
# automagically bumped up to clang 19, which is default on trixie. does not need libclang-rt-14-dev anymore. see (trixie)
RUN apt-get update && apt-get install -y clang libasan8-amd64-cross cmake ninja-build gdb git parallel vim less

# install ccache to speed up (extension) builds. Taken from: https://github.com/duckdb/extension-template?tab=readme-ov-file#tips-for-speedy-builds, 18-09-2025-10-16-am
# also set environment variable to tempfs. Taken from https://wiki.debian.org/ccache#Choose_a_good_ccache_directory
RUN apt-get install -y ccache
ENV CCACHE_DIR=/tmp/ccache

# prepare compiling flockmtl
# installed libcurl-openssl-devel to fix MISSING CURL_LIBRARY CMake Error. Source: https://stackoverflow.com/questions/34914944/could-not-find-curl-missing-curl-library-curl-include-dir-on-cmake
RUN ["apt-get", "install", "-y", "curl", "libcurl4-openssl-dev", "python3", "pipx"]

# packages to be installed taken from makefile after reading https://discourse.cmake.org/t/findcurl-doesnt-set-curl-libraries-and-curl-include-dirs/7619/3
# separated into two distinct RUNs because of reading https://linuxcommandlibrary.com/man/pipx 
RUN ["pipx", "install", "clang-format"]
RUN ["pipx", "install", "cmakelang"]

# install nlohmann_json. needed for flockmtl
# how to use build arguments taken from https://docs.docker.com/build/building/variables/
ARG NLOHMANN_JSON
RUN git clone ${NLOHMANN_JSON} ./nlohmann_json	# used shell form of run because of conversation with Docker docs AI, see 10-09-2025-10-45-am-docker-git-clone.txt
RUN cd ./nlohmann_json &&  cmake -S . -B ./build -G Ninja # the fact that we needed to INSTALL first before we could make flockmtl taken from https://github.com/nlohmann/json/issues/1755#issuecomment-1837675544, 15-09-2025-11-26-am

# install googletest. needed for flockmtl
ARG GTEST
RUN git clone ${GTEST} ./googletest
RUN cd ./googletest && mkdir ./build  && cd ./build && cmake .. && make && make install # how to make and make install googletest taken from https://github.com/google/googletest/tree/main/googletest#build-with-cmake, 15-09-2025-01-22-pm, fixed the whitespace error (mkdir./build) after reading https://stackoverflow.com/questions/63585819/dockerfile-mkdir-not-working-nodealpine, 15-09-2025-02-05-pm


# install vcpkg. source https://learn.microsoft.com/en-us/vcpkg/get_started/get-started?pivots=shell-bash
RUN apt-get install -y zip unzip tar
RUN git clone https://github.com/microsoft/vcpkg.git
RUN cd ./vcpkg && ./bootstrap-vcpkg.sh

RUN ["mkdir", "./DuckDB", "./flockmtl"]

Docker compose file:

# This is a Docker compose file 
# that starts the development environment
# for DuckDB using CLang with Address Sanitizer enabled.
# This bind-mounts the project directory in PATH.
# Skeleton for the file taken from: https://docs.docker.com/engine/storage/bind-mounts/#use-a-bind-mount-with-docker-compose
# Also used info from here: https://docs.docker.com/reference/compose-file/services/#volumes
# How to use env variables taken from: https://docs.docker.com/reference/compose-file/version-and-name/#name-top-level-element, 
# https://docs.docker.com/compose/how-tos/environment-variables/envvars/
# How to use env file taken from: https://serversforhackers.com/c/div-variables-in-docker-compose
# and https://docs.docker.com/compose/how-tos/environment-variables/set-environment-variables/#use-the-env_file-attribute
# Used https://www.yamllint.com/ to check syntax.
# Indentation for bind and create_host_path taken from: https://forums.docker.com/t/creating-directory-instead-of-file/143483/3
# Correct usage of env file taken from conversation with Docker Docs AI: 29-08-2025-1-26-pm-docker-bind-mounts-not-showing.txt
# Read up on networking here:(user-defined-networks) https://docs.docker.com/engine/network/#user-defined-networks
# Took the networks part from here: https://docs.docker.com/compose/intro/compose-application-model/#illustrative-example and ad verbatim from here: https://docs.docker.com/reference/compose-file/networks/#advanced-example
# Took the info that we need the host driver from here: https://docs.docker.com/engine/network/drivers/ and user-defined-networks 

services:
  duckdb-build-env:
    image: ourregistry/duckdb-build-env
    volumes:
      - type: bind
        source: ${SOURCE}
        # the target is an ABSOLUTE path. You have to include the workdir from the Dockerfile if you want that to be the root!
        target: /duckdb-build-env/DuckDB # removed dot because of conversation with docker docs AI: see 28-08-2025-3-14-pm.txt
        read_only: false
        bind:
          create_host_path: false
      - type: bind
        source: ${FLOCKMTL}
        target: /duckdb-build-env/flockmtl
        read_only: false
        bind:
          create_host_path: false
      - type: bind
        source: ${DATASETS}
        target: /duckdb-build-env/datasets
        read_only: false
        bind:
          create_host_path: false
    network_mode: host  # taken from conversation with docker docks AI: see 09-09-2025-11-47-docker-compose-host-network.txt

[westfly]

wget https://raw.githubusercontent.com/duckdb/duckdb/refs/heads/main/extension/extension_build_tools.cmake

and include it in you cmake

include(extension_build_tools.cmake)

[mingtotti]

Got the same issue when configing with dubckdb-vss extension in VSCode, and I solved by adding below configs in vscode settings:

{
    "cmake.configureArgs": [
        "-DDUCKDB_EXTENSION_CONFIGS='${workspaceFolder}/extension_config.cmake'"
    ],
    "cmake.sourceDirectory": "${workspaceFolder}/duckdb",
}

Hope this can help.