Add Nix flake dev shell, custom build/run commands, and CI build/test via nix develop without Conan

[Copilot]

This PR introduces a Nix flake-based development environment for bdd_engine and updates CI to build/test through that same environment. The goal is to make dependency/toolchain provisioning explicit and consistent between local dev and GitHub Actions.

• Build environment: add flake.nix

  • Adds a flake dev shell with the project’s required toolchain/dependencies:
    • gcc14 (for C++26 support)
    • cmake
    • ninja
    • abseil-cpp
    • catch2_3
  • Sets CC/CXX to GCC 14 in the shell hook.
  • Adds repository scripts/ to PATH in the dev shell when the repo root is detectable.

• CI: run configure/build/test inside flake dev shell

  • Replaces previous apt/Conan setup in .github/workflows/cmakeBuildTest.yml with Nix-based setup.
  • Installs Nix (with flakes enabled) and executes build/test via nix develop.
  • Uses the new dev-shell command and explicit test invocation:
    • build release
    • ctest --test-dir cmake_build_release --output-on-failure

• Custom shell scripts

  • Adds new dev-shell commands:
    • build debug|release: configure + build into cmake_build_debug or cmake_build_release
    • run debug|release [args...]: configure + build + run bdd_engine
  • Both commands are executable from any directory in the workspace, while building into fixed repo-root build directories.
  • Removes the legacy scripts/build_and_test.sh script in favor of the new build command + ctest flow.

• Conan removal from repository

  • Removes Conan-managed files:
    • conan_provider.cmake
    • conanfile.py
    • conandata.yml
  • Removes Conan references from workflow, presets, and docs.

• CMake compatibility update

  • Keeps existing abseil::abseil linkage working by adding a fallback alias target when only absl::* targets are available in the environment.
  • Requires Catch2 v3 explicitly (find_package(Catch2 3 REQUIRED)) to match imported headers/targets.

• Docs/config cleanup

  • Updates README.md to document Nix-based commands, including build/run variants and test invocation with ctest.
  • Updates CMakePresets.json, .vscode/c_cpp_properties.json, and .idea/cmake.xml to remove Conan-specific settings.
  • Adds cmake_build/, cmake_build_debug/, and cmake_build_release/ to .gitignore to avoid committing local build artifacts.

nix develop
build debug
build release
run debug
run release
ctest --test-dir cmake_build_release --output-on-failure

Original prompt

Help me to write a flake.nix with a dev shell to build the project with the relevant dependencies.

Write a CI that builds and tests the binary with the new flake.nix

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[BrandonTang89]

The CI builds are failing. Let's just install the necessary libraries via the flake.nix.

Strip out anything regarding the Conan parts from the repo, including the code and docs.

[Copilot]

The CI builds are failing. Let's just install the necessary libraries via the flake.nix.

Strip out anything regarding the Conan parts from the repo, including the code and docs.

Done in commit c05b85c.

I removed Conan from the repository and CI flow, updated flake.nix to provide dependencies directly, and updated docs/presets/editor configs to remove Conan references.

CI now builds/tests via nix develop without Conan.

[BrandonTang89]

There are some build issues related to importing the relevant catch2 headers. Help fix this. Ideally try to ensure it can build before asking me to review again (or inform me if this isn't possible)

[Copilot]

There are some build issues related to importing the relevant catch2 headers. Help fix this. Ideally try to ensure it can build before asking me to review again (or inform me if this isn't possible)

Fixed in commit 12c7fcc.

I updated the flake to use catch2_3 and made CMake explicitly require Catch2 v3 (find_package(Catch2 3 REQUIRED)), which matches the catch2/... headers used by the tests.

I also verified the configure step locally with GCC 14 (cmake -S . -B /tmp/bdd_engine_cfgcheck -DCMAKE_BUILD_TYPE=Release) and it now resolves Catch2 targets correctly.

No UI changes in this update, so there is no UI screenshot to provide.

[BrandonTang89]

Looking better. How about getting custom shell scripts

build

Should configure and do an parallel build with 8 workers for the specified variant (debug or release)

run

should build then run the debug/release variant

Then update the read me with proper docs about how to build and test

[Copilot]

Looking better. How about getting custom shell scripts

build ...

Implemented in commit 80551f1 (with follow-up robustness in b1a44d5).

./scripts/build_and_test.sh is now added and used by CI + README. It supports BUILD_TYPE, BUILD_DIR, and optional PARALLEL_JOBS, and it normalizes to repo root before running.

I validated script syntax and invocation locally; full Nix-path execution isn’t possible in this sandbox (nix unavailable), and the latest workflow runs are currently action_required (no jobs started), so I couldn’t get a fresh CI execution result yet.

No UI changes in this update, so there is no UI screenshot.

[BrandonTang89]

I think I wasn't clear. I want 2 custom commands within the dev shell

build debug/release
run debug/release

That configure+build and configure+build+run the relevant variants of the binary

These should be executable from any directory within the workspace and still build the binary in the right placea and run it from the directory the command is run at

[Copilot]

I think I wasn't clear. I want 2 custom commands within the dev shell

build debug/release...

Implemented in commits 9b546db and 7dbbc85.

You can now use build debug|release and run debug|release from anywhere in the workspace (inside nix develop). They always configure/build into ${repo}/cmake_build_debug or ${repo}/cmake_build_release, and run executes the built bdd_engine from the directory where you invoke the command.

No UI changes in this update, so there is no UI screenshot.

[BrandonTang89]

Almost there. Remove the build_and_test shell script and replace it's use within the CI with just using the newly implemented build command and cmake test

[Copilot]

Almost there. Remove the build_and_test shell script and replace it's use within the CI with just using the newly implemented build command and cmake test

Done in commits aa173f4 and 0f022ba.

CI no longer uses scripts/build_and_test.sh (script removed). It now runs build release and then ctest --test-dir cmake_build_release --output-on-failure inside nix develop.

[Copilot]

Pull request overview

This PR migrates the project’s developer/CI build environment from Conan/apt-based provisioning to a Nix flake dev shell, and introduces repo-local build/run helper commands to standardize local workflows and CI execution.

Changes:

• Add flake.nix providing a GCC14/CMake/Ninja/Abseil/Catch2 dev shell and PATH wiring for scripts/.
• Introduce scripts/build and scripts/run commands and update CI to build/test via nix develop.
• Remove Conan integration files and clean up related presets/editor configs/docs/ignore rules.

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
scripts/build	Adds a build helper to configure/build Debug or Release into fixed build dirs.
scripts/run	Adds a run helper to build then execute the compiled bdd_engine binary.
flake.nix	Introduces Nix flake dev shell with toolchain and dependencies.
.github/workflows/cmakeBuildTest.yml	Updates CI to build/test inside nix develop instead of apt/Conan.
CMakeLists.txt	Requires Catch2 v3 and adds an Abseil target alias fallback.
CMakePresets.json	Removes Conan vendor integration and Conan-specific top-level include.
README.md	Updates build/test documentation to Nix + build/ctest flow and removes Conan profile guidance.
.gitignore	Adds ignore rules for new build directories and flake.lock.
.vscode/c_cpp_properties.json	Removes Conan include path reference.
.idea/cmake.xml	Removes Conan top-level include from IDE generation options.
conan_provider.cmake	Removed (Conan provider no longer used).
conanfile.py	Removed (Conan no longer used).
conandata.yml	Removed (Conan no longer used).

Files not reviewed (1)

• .idea/cmake.xml: Language not supported

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[Copilot]

The shellHook only adds scripts/ to PATH when git is available and git rev-parse succeeds. That contradicts the README claim that build/run work from anywhere, and can break in minimal environments or source exports without .git (where build won’t be found). Consider adding git to the devShell packages or using a non-git fallback repo-root detection (e.g., walking up from $PWD for flake.nix/scripts/).

Suggested change

	if command -v git >/dev/null 2>&1; then
	REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || true)"
	if [ -n "$REPO_ROOT" ] && [ -d "$REPO_ROOT/scripts" ]; then
	export PATH="$REPO_ROOT/scripts:$PATH"
	fi
	fi
	REPO_ROOT=""
	if command -v git >/dev/null 2>&1; then
	REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || true)"
	fi
	if [ -z "$REPO_ROOT" ]; then
	search_dir="$PWD"
	while [ "$search_dir" != "/" ]; do
	if [ -d "$search_dir/scripts" ]; then
	REPO_ROOT="$search_dir"
	break
	fi
	search_dir="$(dirname "$search_dir")"
	done
	fi
	if [ -n "$REPO_ROOT" ] && [ -d "$REPO_ROOT/scripts" ]; then
	export PATH="$REPO_ROOT/scripts:$PATH"
	fi

[Copilot]

find_package(absl) is not marked REQUIRED, but the project unconditionally includes Abseil headers and links against abseil::abseil. With the fallback target below, CMake can configure successfully even when Abseil isn’t found (leading to later, harder-to-debug compile/link failures). Make Abseil discovery fail fast (e.g., find_package(absl REQUIRED) / CONFIG REQUIRED) and/or emit a fatal error if the expected absl::* targets are missing before creating abseil::abseil.