Preliminary bzlmod support

.bazelrc

@@ -6,4 +6,6 @@ common:ghc_9_2_7 --repo_env=GHC_VERSION=9.2.7
 
 common:ghc_9_4_5 --repo_env=GHC_VERSION=9.4.5
 
+common:bzlmod --enable_bzlmod
+
 try-import .bazelrc.local

.github/workflows/workflow.yaml

@@ -17,6 +17,11 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         ghc-version: [ghc_8_10_7, ghc_9_0_2, ghc_9_2_7, ghc_9_4_5]
+        enable-bzlmod: [false]
+        include:
+          - os: ubuntu-latest
+            ghc-version: ghc_9_4_5
+            enable-bzlmod: true
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -38,20 +43,27 @@ jobs:
               cache_setting="--remote_header=x-buildbuddy-api-key=$BUILDBUDDY_API_KEY"
           fi
 
+          bzlmod_setting=
+          if [[ ${{ matrix.enable-bzlmod }} = true ]]; then
+            bzlmod_setting="common --config=bzlmod"
+          fi
+
           cat >.bazelrc.local <<EOF
-          build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host
+          build --host_platform=@rules_nixpkgs_core//platforms:host
           build --bes_results_url=https://app.buildbuddy.io/invocation/
           build --bes_backend=grpcs://cloud.buildbuddy.io
           build --remote_cache=grpcs://cloud.buildbuddy.io
           build $cache_setting
           build --remote_timeout=600
           build --keep_backend_build_event_connections_alive=false
           build --repository_cache=~/repo-cache/
+          $bzlmod_setting
           EOF
           ln -s ../.bazelrc.local example/.bazelrc.local
           ln -s ../../.bazelrc.local tests/alternative-deps/.bazelrc.local
       - name: Build & test
         run: nix-shell --pure --run 'bazel test --config=${{ matrix.ghc-version }} --test_output=all //...'
+        if: ${{ !matrix.enable-bzlmod }}
       - name: Test the example
         run: |
           cd example
@@ -113,5 +125,7 @@ jobs:
           nix-shell --pure --run 'bazel run //:gazelle --config=${{ matrix.ghc-version }}'
           nix-shell --pure --run 'bazel run //:gazelle-update-repos --config=${{ matrix.ghc-version }}'
           nix-shell --pure --run 'bazel test //... --config=${{ matrix.ghc-version }}'
+        if: ${{ !matrix.enable-bzlmod }}
       - name: Test for buildifier suggestions
         run: nix-shell --pure --run 'bazel run //:buildifier-diff'
+        if: ${{ !matrix.enable-bzlmod }}

MODULE.bazel

@@ -0,0 +1,21 @@
+module(
+    name = "gazelle_cabal",
+    version = "0.0.0",
+)
+
+bazel_dep(name = "rules_haskell")
+
+stack_snapshot = use_extension(
+    "@rules_haskell//extensions:stack_snapshot.bzl",
+    "stack_snapshot",
+)
+use_repo(stack_snapshot, "stackage")
+stack_snapshot.package(name = "directory")
+stack_snapshot.package(name = "filepath")
+stack_snapshot.package(name = "json")
+
+non_module_deps = use_extension("//:non_module_deps.bzl", "non_module_deps")
+use_repo(non_module_deps, "io_tweag_gazelle_cabal_deps")
+
+bazel_dep(name = "rules_go", version = "0.41.0", repo_name = "io_bazel_rules_go")
+bazel_dep(name = "gazelle", version = "0.33.0", repo_name = "bazel_gazelle")

README.md

@@ -216,14 +216,13 @@ configuration with default flag values.
 ## Hacking on gazelle_cabal with nix
 
 If you are running NixOS or if you want to provision `ghc` and other dependencies using `nix`,
-you'll need to set the `host_platform` config option to `@io_tweag_rules_nixpkgs//nixpkgs/platforms:host`:
+you'll need to set the `host_platform` config option to `@rules_nixpkgs_core//platforms:host`:
 ```sh
-> bazel build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host ...
+> bazel build --host_platform=@rules_nixpkgs_core//platforms:host ...
 ```
 For ease of use, we recommend setting this in your `.bazelrc.local` file:
 ```sh
-echo "build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host" >> .bazelrc.local
-echo "run --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host" >> .bazelrc.local
+echo "build --host_platform=@rules_nixpkgs_core//platforms:host" >> .bazelrc.local
 ```
 
 ## Sponsors

WORKSPACE

@@ -17,17 +17,15 @@ load("@rules_haskell//haskell:repositories.bzl", "rules_haskell_dependencies")
 
 rules_haskell_dependencies()
 
-load(
-    "@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl",
-    "nixpkgs_local_repository",
-    "nixpkgs_python_configure",
-)
+load("@rules_nixpkgs_core//:nixpkgs.bzl", "nixpkgs_local_repository")
 
 nixpkgs_local_repository(
     name = "nixpkgs",
     nix_file = "//:nixpkgs.nix",
 )
 
+load("@rules_nixpkgs_python//:python.bzl", "nixpkgs_python_configure")
+
 nixpkgs_python_configure(repository = "@nixpkgs")
 
 load("@rules_haskell//haskell:cabal.bzl", "stack_snapshot")
@@ -41,7 +39,7 @@ load("//:config_settings/setup.bzl", "config_settings")
 config_settings(name = "config_settings")
 
 load("@config_settings//:info.bzl", "ghc_version")
-load("@io_tweag_gazelle_cabal//:defs.bzl", "gazelle_cabal_dependencies")
+load("//:defs.bzl", "gazelle_cabal_dependencies")
 
 gazelle_cabal_dependencies()
 
@@ -115,10 +113,7 @@ http_archive(
     ],
 )
 
-load(
-    "@io_tweag_rules_nixpkgs//nixpkgs:toolchains/go.bzl",
-    "nixpkgs_go_configure",
-)
+load("@rules_nixpkgs_go//:go.bzl", "nixpkgs_go_configure")
 
 nixpkgs_go_configure(repository = "@nixpkgs")
 

example/MODULE.bazel

@@ -0,0 +1,118 @@
+module(name = "gazelle_cabal_example")
+
+bazel_dep(name = "gazelle_cabal", repo_name = "io_tweag_gazelle_cabal")
+local_path_override(module_name = "gazelle_cabal", path = "..")
+
+bazel_dep(name = "rules_haskell")
+bazel_dep(name = "rules_haskell_nix")
+bazel_dep(name = "rules_go", version = "0.41.0", repo_name = "io_bazel_rules_go")
+bazel_dep(name = "gazelle", version = "0.33.0", repo_name = "bazel_gazelle")
+
+stack_snapshot = use_extension(
+    "@rules_haskell//extensions:stack_snapshot.bzl",
+    "stack_snapshot",
+)
+use_repo(stack_snapshot, "stackage", "stackage-exe")
+# TODO these should be generated by Gazelle
+stack_snapshot.package(name = "base")
+stack_snapshot.package(name = "inspection-testing")
+stack_snapshot.package(name = "mtl")
+stack_snapshot.package(name = "tasty")
+stack_snapshot.package(
+    name = "tasty-discover",
+    components = [
+        "lib",
+        "exe:tasty-discover",
+    ],
+)
+stack_snapshot.package(name = "tasty-hunit")
+stack_snapshot.package(name = "text")
+stack_snapshot.package(name = "void")
+
+# TODO replace this once a proper public interface for Nix provided Haskell toolchains exists.
+nix_haskell_toolchains = use_extension(
+    "@rules_haskell_nix//extensions:nix_haskell_toolchains.bzl",
+    "nix_haskell_toolchains",
+)
+
+GHC_VERSION = "9.4.5"
+nix_haskell_toolchains.new(
+    attribute_path = "haskell.compiler.ghc" + GHC_VERSION.replace(".", ""),
+    repository = "@nixpkgs",
+    version = GHC_VERSION,
+)
+use_repo(
+    nix_haskell_toolchains,
+    "nix_haskell_toolchains_configurations",
+    # TODO register via rules_nixpkgs_posix once supported.
+    "all_posix_toolchains",
+)
+
+# TODO remove this once a proper public interface for Nix provided Haskell toolchain exists.
+declare_nix_toolchains = use_extension(
+    "@rules_haskell_nix//private:declare_toolchains.bzl",
+    "declare_nix_toolchains",
+)
+use_repo(
+    declare_nix_toolchains,
+    "all_nix_toolchains",
+)
+
+register_toolchains(
+    "@all_nix_toolchains//:all",
+    "@all_posix_toolchains//:all",
+)
+
+# TODO Remove once rules_haskell is in the BCR.
+RULES_HASKELL_REV = "155ba21c7d315cc421ee3f17a1c09b758cc7279d"
+RULES_HASKELL_INTEGRITY = "sha384-dIsFufYml0KGSUiC6jhY9ClMv/yEW1kGof7fLahSwfbWd28jLiwMGBGUuoOsQwWf"
+archive_override(
+    module_name = "rules_haskell",
+    urls = ["https://github.com/tweag/rules_haskell/archive/%s.tar.gz" % RULES_HASKELL_REV],
+    strip_prefix = "rules_haskell-%s" % RULES_HASKELL_REV,
+    integrity = RULES_HASKELL_INTEGRITY,
+)
+archive_override(
+    module_name = "rules_haskell_nix",
+    urls = ["https://github.com/tweag/rules_haskell/archive/%s.tar.gz" % RULES_HASKELL_REV],
+    strip_prefix = "rules_haskell-%s/rules_haskell_nix" % RULES_HASKELL_REV,
+    integrity = RULES_HASKELL_INTEGRITY,
+)
+
+# Needed for custom toolchain definitions in non_module_deps.
+# TODO update once a bzlmod API for Nix provided toolchains exists.
+bazel_dep(name = "rules_nixpkgs_core")
+bazel_dep(name = "rules_nixpkgs_cc")
+bazel_dep(name = "rules_nixpkgs_posix")
+bazel_dep(name = "platforms", version = "0.0.7")
+bazel_dep(name = "rules_cc", version = "0.0.9")
+
+# TODO Remove once rules_nixpkgs is in the BCR.
+RULES_NIXPKGS_REV = "7e627d76ba65d6c42586fc265e46bd370672b4eb"
+RULES_NIXPKGS_INTEGRITY = "sha384-N2bS5BvSk8QMjhmuxdeeve9PBJUTwFOHufMV4sDgaviwXNdCGc7JaJPqwqZV1TbC"
+archive_override(
+    module_name = "rules_nixpkgs_core",
+    urls = ["https://github.com/tweag/rules_nixpkgs/archive/%s.tar.gz" % RULES_NIXPKGS_REV],
+    strip_prefix = "rules_nixpkgs-%s/core" % RULES_NIXPKGS_REV,
+    integrity = RULES_NIXPKGS_INTEGRITY,
+)
+archive_override(
+    module_name = "rules_nixpkgs_cc",
+    urls = ["https://github.com/tweag/rules_nixpkgs/archive/%s.tar.gz" % RULES_NIXPKGS_REV],
+    strip_prefix = "rules_nixpkgs-%s/toolchains/cc" % RULES_NIXPKGS_REV,
+    integrity = RULES_NIXPKGS_INTEGRITY,
+)
+archive_override(
+    module_name = "rules_nixpkgs_posix",
+    urls = ["https://github.com/tweag/rules_nixpkgs/archive/%s.tar.gz" % RULES_NIXPKGS_REV],
+    strip_prefix = "rules_nixpkgs-%s/toolchains/posix" % RULES_NIXPKGS_REV,
+    integrity = RULES_NIXPKGS_INTEGRITY,
+)
+
+non_module_deps = use_extension("//:non_module_deps.bzl", "non_module_deps")
+use_repo(non_module_deps, "nixpkgs")
+use_repo(non_module_deps, "nixpkgs_config_cc")
+use_repo(non_module_deps, "nixpkgs_config_cc_info")
+use_repo(non_module_deps, "nixpkgs_config_cc_toolchains")
+use_repo(non_module_deps, "zlib.dev")
+register_toolchains("@nixpkgs_config_cc_toolchains//:all")

example/README.md

@@ -2,7 +2,8 @@ This is an example project using the [gazelle_cabal][gazelle_cabal] extension.
 
 Run the following to generate the build configuration from the Cabal files.
 ```bazel
-echo "build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host" > .bazelrc.local
+
+echo "build --host_platform=@rules_nixpkgs_core//platforms:host" > .bazelrc.local
 nix-shell --pure --run "bazel run //:gazelle"
 nix-shell --pure --run "bazel run //:gazelle-update-repos"
 ```

example/WORKSPACE

@@ -22,18 +22,15 @@ load("@rules_haskell//haskell:repositories.bzl", "rules_haskell_dependencies")
 
 rules_haskell_dependencies()
 
-load(
-    "@io_tweag_rules_nixpkgs//nixpkgs:nixpkgs.bzl",
-    "nixpkgs_local_repository",
-    "nixpkgs_package",
-    "nixpkgs_python_configure",
-)
+load("@rules_nixpkgs_core//:nixpkgs.bzl", "nixpkgs_local_repository")
 
 nixpkgs_local_repository(
     name = "nixpkgs",
     nix_file = "//:nixpkgs.nix",
 )
 
+load("@rules_nixpkgs_python//:python.bzl", "nixpkgs_python_configure")
+
 nixpkgs_python_configure(repository = "@nixpkgs")
 
 load("@rules_haskell//haskell:cabal.bzl", "stack_snapshot")
@@ -96,10 +93,7 @@ http_archive(
     ],
 )
 
-load(
-    "@io_tweag_rules_nixpkgs//nixpkgs:toolchains/go.bzl",
-    "nixpkgs_go_configure",
-)
+load("@rules_nixpkgs_go//:go.bzl", "nixpkgs_go_configure")
 
 nixpkgs_go_configure(repository = "@nixpkgs")
 
@@ -136,6 +130,8 @@ gazelle_dependencies()
 # zlib
 ####################
 
+load("@rules_nixpkgs_core//:nixpkgs.bzl", "nixpkgs_package")
+
 nixpkgs_package(
     name = "nixpkgs_zlib",
     attribute_path = "zlib",

example/non_module_deps.bzl

@@ -0,0 +1,57 @@
+load(
+    "@rules_nixpkgs_core//:nixpkgs.bzl",
+    "nixpkgs_local_repository",
+    "nixpkgs_package",
+)
+load("@rules_nixpkgs_cc//:cc.bzl", "nixpkgs_cc_configure")
+
+def _non_module_deps_impl(_ctx):
+    nixpkgs_local_repository(
+        name = "nixpkgs",
+        nix_file = "//:nixpkgs.nix",
+    )
+
+    nixpkgs_cc_configure(
+        name = "nixpkgs_config_cc",
+        repository = "@nixpkgs",
+        register = False,
+    )
+
+    nixpkgs_package(
+        name = "nixpkgs_zlib",
+        attribute_path = "zlib",
+        repository = "@nixpkgs",
+    )
+
+    nixpkgs_package(
+        name = "zlib.dev",
+        build_file_content = """
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+filegroup(
+    name = "include",
+    srcs = glob(["include/*.h"]),
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "zlib",
+    srcs = ["@nixpkgs_zlib//:lib"],
+    hdrs = [":include"],
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+    # This rule only bundles headers and a library and doesn't compile or link by itself.
+    # We set linkstatic = 1 to quiet to quiet the following warning:
+    #
+    #   in linkstatic attribute of cc_library rule @zlib.dev//:zlib:
+    #   setting 'linkstatic=1' is recommended if there are no object files.
+    #
+    linkstatic = 1,
+)
+""",
+        repository = "@nixpkgs",
+    )
+
+non_module_deps = module_extension(
+    implementation = _non_module_deps_impl,
+)

gazelle_cabal/BUILD.bazel

@@ -6,7 +6,7 @@ go_library(
         "dependency_resolution.go",
         "lang.go",
     ],
-    data = ["@io_tweag_gazelle_cabal//cabalscan"],
+    data = ["//cabalscan"],
     importpath = "github.com/tweag/gazelle_cabal/gazelle_cabal",
     visibility = ["//visibility:public"],
     deps = [

non_module_deps.bzl

@@ -0,0 +1,11 @@
+load("//:defs.bzl", "gazelle_cabal_dependencies")
+
+def _non_module_deps_impl(_ctx):
+    # TODO[AH]: This is only required for backward compatibility to WORKSPACE mode.
+    #   Once WORKSPACE mode support is removed we can directly reference the
+    #   `@stackage//...` labels for the dependencies introduced by this macro.
+    gazelle_cabal_dependencies()
+
+non_module_deps = module_extension(
+    implementation = _non_module_deps_impl,
+)

tests/alternative-deps/README.md

@@ -3,7 +3,7 @@ It tests using other repository names than `stackage` from which to get dependen
 
 Run the following to generate the build configuration from the Cabal files.
 ```bazel
-echo "build --host_platform=@io_tweag_rules_nixpkgs//nixpkgs/platforms:host" > .bazelrc.local
+echo "build --host_platform=@rules_nixpkgs_core//platforms:host" > .bazelrc.local
 nix-shell --pure --run "bazel run //:gazelle"
 nix-shell --pure --run "bazel run //:gazelle-update-repos"
 ```