WIP: Bazel template

WIP: use new MODULE.bazel system.
WIP: use `.bazel` extension on BUILD files.

templates/c++-bazel/.bazelignore

@@ -0,0 +1,3 @@
+.pre-commit-config.yaml
+result
+.direnv

templates/c++-bazel/.bazelrc

@@ -0,0 +1,6 @@
+# rule_nixpkgs' specific configuration
+build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host
+build --crosstool_top=@nixpkgs_config_cc//:toolchain
+
+# Use C++20
+build:linux --cxxopt=-std=c++20

templates/c++-bazel/.clang-format

@@ -0,0 +1,23 @@
+# vim: ft=yaml
+---
+BasedOnStyle: LLVM
+IndentWidth: 4
+---
+Language: Cpp
+# Force pointers to the type for C++.
+DerivePointerAlignment: false
+PointerAlignment: Left
+
+# Short functions should not be on a single line, unless empty
+AllowShortFunctionsOnASingleLine: Empty
+
+# Make them level
+AccessModifierOffset: -4
+
+# It makes more sense this way
+BreakBeforeBinaryOperators: All
+BreakBeforeTernaryOperators: true
+
+# Aesthetic
+AlignOperands: AlignAfterOperator
+---

templates/c++-bazel/.envrc

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+if ! has nix_direnv_version || ! nix_direnv_version 3.0.0; then
+    source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.0/direnvrc" "sha256-21TMnI2xWX7HkSTjFFri2UaohXVj854mgvWapWrxRXg="
+fi
+
+use flake

templates/c++-bazel/.gitignore

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+# Bazel build directories
+/bazel-*/
+
+# Nix generated files
+/.pre-commit-config.yaml
+/result

templates/c++-bazel/.woodpecker/check.yml

@@ -0,0 +1,31 @@
+labels:
+  backend: local
+
+steps:
+- name: pre-commit check
+  image: bash
+  commands:
+  - nix develop --command pre-commit run --all
+
+- name: nix flake check
+  image: bash
+  commands:
+  - nix flake check
+
+- name: notifiy
+  image: bash
+  environment:
+    ADDRESS:
+      from_secret: matrix_homeserver
+    ROOM:
+      from_secret: matrix_roomid
+    USER:
+      from_secret: matrix_username
+    PASS:
+      from_secret: matrix_password
+  commands:
+  - nix run github:ambroisie/matrix-notifier
+  when:
+    status:
+    - failure
+    - success

templates/c++-bazel/WORKSPACE

@@ -0,0 +1,48 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "io_tweag_rules_nixpkgs",
+    sha256 = "980edfceef2e59e1122d9be6c52413bc298435f0a3d452532b8a48d7562ffd67",
+    strip_prefix = "rules_nixpkgs-0.10.0",
+    urls = ["https://github.com/tweag/rules_nixpkgs/releases/download/v0.10.0/rules_nixpkgs-0.10.0.tar.gz"],
+)
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:repositories.bzl", "rules_nixpkgs_dependencies")
+
+# load everything that rules_nixpkgs rules need to work
+rules_nixpkgs_dependencies()
+
+load("@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl", "nixpkgs_cc_configure", "nixpkgs_local_repository")
+
+# Define nixpkgs version using the flakes lock file.
+nixpkgs_local_repository(
+    name = "nixpkgs",
+    nix_file_deps = ["//:flake.lock"],
+    nix_flake_lock_file = "//:flake.lock",
+)
+
+nixpkgs_cc_configure(
+    name = "nixpkgs_config_cc",
+    repository = "@nixpkgs",
+)
+
+# load rules_cc
+http_archive(
+    name = "rules_cc",
+    sha256 = "4dccbfd22c0def164c8f47458bd50e0c7148f3d92002cdb459c2a96a68498241",
+    urls = ["https://github.com/bazelbuild/rules_cc/releases/download/0.0.1/rules_cc-0.0.1.tar.gz"],
+)
+
+load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies", "rules_cc_toolchains")
+
+rules_cc_dependencies()
+
+rules_cc_toolchains()
+
+# Load dependencies
+http_archive(
+    name = "com_google_googletest",
+    sha256 = "8ad598c73ad796e0d8280b082cebd82a630d73e73cd3c70057938a6501bba5d7",
+    strip_prefix = "googletest-1.14.0",
+    urls = ["https://github.com/google/googletest/archive/refs/tags/v1.14.0.tar.gz"],
+)

templates/c++-bazel/flake.lock

@@ -0,0 +1,143 @@
+{
+  "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1673956053,
+        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "futils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1694529238,
+        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "ref": "main",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "gitignore": {
+      "inputs": {
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1660459072,
+        "narHash": "sha256-8DFJjXG8zqoONA1vXtgeKXy68KdJL5UaXR8NtVMUbx8=",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "a20de23b925fd8264fd7fad6454652e142fd7f73",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1698134075,
+        "narHash": "sha256-foCD+nuKzfh49bIoiCBur4+Fx1nozo+4C/6k8BYk4sg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "8efd5d1e283604f75a808a20e6cde0ef313d07d4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1685801374,
+        "narHash": "sha256-otaSUoFEMM+LjBI1XL/xGB5ao6IwnZOXc47qhIgJe8U=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c37ca420157f4abc31e26f436c1145f8951ff373",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": [
+          "futils"
+        ],
+        "gitignore": "gitignore",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "nixpkgs-stable": "nixpkgs-stable"
+      },
+      "locked": {
+        "lastModified": 1698227354,
+        "narHash": "sha256-Fi5H9jbaQLmLw9qBi/mkR33CoFjNbobo5xWdX4tKz1Q=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "bd38df3d508dfcdff52cd243d297f218ed2257bf",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "master",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "futils": "futils",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

templates/c++-bazel/flake.nix

@@ -0,0 +1,126 @@
+{
+  description = "A C++ project";
+
+  inputs = {
+    futils = {
+      type = "github";
+      owner = "numtide";
+      repo = "flake-utils";
+      ref = "main";
+    };
+
+    nixpkgs = {
+      type = "github";
+      owner = "NixOS";
+      repo = "nixpkgs";
+      ref = "nixos-unstable";
+    };
+
+    pre-commit-hooks = {
+      type = "github";
+      owner = "cachix";
+      repo = "pre-commit-hooks.nix";
+      ref = "master";
+      inputs = {
+        flake-utils.follows = "futils";
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+  };
+
+  outputs = { self, futils, nixpkgs, pre-commit-hooks }:
+    {
+      overlays = {
+        default = final: _prev: {
+          project = with final; buildBazelPackage {
+            pname = "project";
+            version = "0.0.0";
+
+            src = self;
+
+            inherit (pkgs) bazel;
+
+            fetchAttrs = {
+              # Fixed output derivation hash after bazel fetch.
+              # This varies per platform, probably from the JDK pulled in being part
+              # of the output derivation ? Is there a more robust way to do this ?
+              # (Hashes extracted from the ofborg build logs)
+              sha256 = let inherit (stdenv.hostPlatform) system; in {
+                x86_64-linux = "${lib.fakeHash}";
+              }.${system} or (throw "No hash for system: ${system}");
+
+
+              # Use WORKSPACE file to fetch `rule_cc`
+              removeRulesCC = false;
+            };
+
+            buildAttrs = {
+              installPhase = ''
+                mkdir -p "$out/bin"
+
+                install bazel-bin/src/project "$out/bin"
+              '';
+            };
+
+            doCheck = true;
+
+            meta = with lib; {
+              description = "A C++ project";
+              homepage = "https://gitea.belanyi.fr/ambroisie/project";
+              license = licenses.mit;
+              maintainers = with maintainers; [ ambroisie ];
+              platforms = platforms.unix;
+            };
+          };
+        };
+      };
+    } // futils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [
+            self.overlays.default
+          ];
+        };
+
+        pre-commit = pre-commit-hooks.lib.${system}.run {
+          src = self;
+
+          hooks = {
+            nixpkgs-fmt = {
+              enable = true;
+            };
+
+            clang-format = {
+              enable = true;
+            };
+          };
+        };
+      in
+      {
+        checks = {
+          inherit (self.packages.${system}) project;
+
+          inherit pre-commit;
+        };
+
+        devShells = {
+          default = pkgs.mkShellNoCC {
+            inputsFrom = with self.packages.${system}; [
+              project
+            ];
+
+            packages = with pkgs; [
+              clang-tools
+            ];
+
+            inherit (pre-commit) shellHook;
+          };
+        };
+
+        packages = futils.lib.flattenTree {
+          default = pkgs.project;
+          inherit (pkgs) project;
+        };
+      });
+}

templates/c++-bazel/src/BUILD

@@ -0,0 +1,6 @@
+cc_binary(
+    name = "project",
+    srcs = [
+        "main.cc",
+    ],
+)

templates/c++-bazel/src/main.cc

@@ -0,0 +1,5 @@
+#include <iostream>
+
+int main() {
+    std::cout << "Hello World!\n";
+}

templates/c++-bazel/tests/unit/BUILD

@@ -0,0 +1,10 @@
+cc_test(
+    name = "dummy_test",
+    size = "small",
+    srcs = [
+        "dummy_test.cc",
+    ],
+    deps = [
+        "@com_google_googletest//:gtest_main",
+    ],
+)

templates/c++-bazel/tests/unit/dummy_test.cc

@@ -0,0 +1,5 @@
+#include <gtest/gtest.h>
+
+TEST(misc, passing) {
+    ASSERT_EQ(1, 1);
+}