From 7a6269ba7b37a31bdc4b7ec539d45adf860f5623 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Fri, 5 Jul 2024 16:21:20 -0400
Subject: [PATCH] Package the Nix CLI with Meson

Co-Authored-By: Qyriad <qyriad@qyriad.me>
---
 meson.build                 |   3 +
 packaging/components.nix    |   3 +
 packaging/hydra.nix         |   1 +
 src/nix/.version            |   1 +
 src/nix/build-remote        |   1 +
 src/nix/build-utils-meson   |   1 +
 src/nix/doc                 |   1 +
 src/nix/help-stores.md      |   1 +
 src/nix/local.mk            |  21 ++---
 src/nix/main.cc             |   2 +-
 src/nix/meson.build         | 170 ++++++++++++++++++++++++++++++++++++
 src/nix/nix-build           |   1 +
 src/nix/nix-channel         |   1 +
 src/nix/nix-collect-garbage |   1 +
 src/nix/nix-copy-closure    |   1 +
 src/nix/nix-env             |   1 +
 src/nix/nix-instantiate     |   1 +
 src/nix/nix-store           |   1 +
 src/nix/package.nix         | 129 +++++++++++++++++++++++++++
 src/nix/profile.md          |   2 +-
 src/nix/profiles.md         |   1 +
 21 files changed, 326 insertions(+), 18 deletions(-)
 create mode 120000 src/nix/.version
 create mode 120000 src/nix/build-remote
 create mode 120000 src/nix/build-utils-meson
 create mode 120000 src/nix/doc
 create mode 120000 src/nix/help-stores.md
 create mode 100644 src/nix/meson.build
 create mode 120000 src/nix/nix-build
 create mode 120000 src/nix/nix-channel
 create mode 120000 src/nix/nix-collect-garbage
 create mode 120000 src/nix/nix-copy-closure
 create mode 120000 src/nix/nix-env
 create mode 120000 src/nix/nix-instantiate
 create mode 120000 src/nix/nix-store
 create mode 100644 src/nix/package.nix
 create mode 120000 src/nix/profiles.md

diff --git a/meson.build b/meson.build
index f09998ab6..e6bdc2eac 100644
--- a/meson.build
+++ b/meson.build
@@ -15,6 +15,9 @@ subproject('libflake')
 subproject('libmain')
 subproject('libcmd')
 
+# Executables
+subproject('nix')
+
 # Docs
 subproject('internal-api-docs')
 subproject('external-api-docs')
diff --git a/packaging/components.nix b/packaging/components.nix
index f1cd3b9c6..0e369a055 100644
--- a/packaging/components.nix
+++ b/packaging/components.nix
@@ -32,6 +32,9 @@ in
 
   nix-cmd = callPackage ../src/libcmd/package.nix { };
 
+  # Will replace `nix` once the old build system is gone.
+  nix-ng = callPackage ../src/nix/package.nix { };
+
   nix-internal-api-docs = callPackage ../src/internal-api-docs/package.nix { };
   nix-external-api-docs = callPackage ../src/external-api-docs/package.nix { };
 
diff --git a/packaging/hydra.nix b/packaging/hydra.nix
index 0bbbc31f7..4dfaf9bbf 100644
--- a/packaging/hydra.nix
+++ b/packaging/hydra.nix
@@ -53,6 +53,7 @@ let
     "nix-flake-tests"
     "nix-main"
     "nix-cmd"
+    "nix-ng"
   ];
 in
 {
diff --git a/src/nix/.version b/src/nix/.version
new file mode 120000
index 000000000..b7badcd0c
--- /dev/null
+++ b/src/nix/.version
@@ -0,0 +1 @@
+../../.version
\ No newline at end of file
diff --git a/src/nix/build-remote b/src/nix/build-remote
new file mode 120000
index 000000000..2cea44d46
--- /dev/null
+++ b/src/nix/build-remote
@@ -0,0 +1 @@
+../build-remote
\ No newline at end of file
diff --git a/src/nix/build-utils-meson b/src/nix/build-utils-meson
new file mode 120000
index 000000000..91937f183
--- /dev/null
+++ b/src/nix/build-utils-meson
@@ -0,0 +1 @@
+../../build-utils-meson/
\ No newline at end of file
diff --git a/src/nix/doc b/src/nix/doc
new file mode 120000
index 000000000..7e57b0f58
--- /dev/null
+++ b/src/nix/doc
@@ -0,0 +1 @@
+../../doc
\ No newline at end of file
diff --git a/src/nix/help-stores.md b/src/nix/help-stores.md
new file mode 120000
index 000000000..5c5624f5e
--- /dev/null
+++ b/src/nix/help-stores.md
@@ -0,0 +1 @@
+../../doc/manual/src/store/types/index.md.in
\ No newline at end of file
diff --git a/src/nix/local.mk b/src/nix/local.mk
index 4b6117330..28b30b586 100644
--- a/src/nix/local.mk
+++ b/src/nix/local.mk
@@ -42,27 +42,16 @@ $(eval $(call install-symlink, $(bindir)/nix, $(libexecdir)/nix/build-remote))
 
 src/nix-env/user-env.cc: src/nix-env/buildenv.nix.gen.hh
 
-src/nix/develop.cc: src/nix/get-env.sh.gen.hh
+$(d)/develop.cc: $(d)/get-env.sh.gen.hh
 
 src/nix-channel/nix-channel.cc: src/nix-channel/unpack-channel.nix.gen.hh
 
-src/nix/main.cc: \
+$(d)/main.cc: \
   doc/manual/generate-manpage.nix.gen.hh \
   doc/manual/utils.nix.gen.hh doc/manual/generate-settings.nix.gen.hh \
   doc/manual/generate-store-info.nix.gen.hh \
-  src/nix/generated-doc/help-stores.md
+  $(d)/help-stores.md.gen.hh
 
-src/nix/generated-doc/files/%.md: doc/manual/src/command-ref/files/%.md
-	@mkdir -p $$(dirname $@)
-	@cp $< $@
+$(d)/profile.cc: $(d)/profile.md
 
-src/nix/profile.cc: src/nix/profile.md src/nix/generated-doc/files/profiles.md.gen.hh
-
-src/nix/generated-doc/help-stores.md: doc/manual/src/store/types/index.md.in
-	@mkdir -p $$(dirname $@)
-	@echo 'R"(' >> $@.tmp
-	@echo >> $@.tmp
-	@cat $^ >> $@.tmp
-	@echo >> $@.tmp
-	@echo ')"' >> $@.tmp
-	@mv $@.tmp $@
+$(d)/profile.md: $(d)/profiles.md.gen.hh
diff --git a/src/nix/main.cc b/src/nix/main.cc
index de6d89bd3..c90bb25a7 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -333,7 +333,7 @@ struct CmdHelpStores : Command
     std::string doc() override
     {
         return
-          #include "generated-doc/help-stores.md"
+          #include "help-stores.md.gen.hh"
           ;
     }
 
diff --git a/src/nix/meson.build b/src/nix/meson.build
new file mode 100644
index 000000000..dd21c4b1b
--- /dev/null
+++ b/src/nix/meson.build
@@ -0,0 +1,170 @@
+project('nix', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+  dependency('nix-util'),
+  dependency('nix-store'),
+  dependency('nix-expr'),
+  dependency('nix-fetchers'),
+  dependency('nix-main'),
+  dependency('nix-cmd'),
+]
+deps_public_maybe_subproject = [
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/export-all-symbols')
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  '-include', 'config-expr.hh',
+  #'-include', 'config-fetchers.hh',
+  '-include', 'config-main.hh',
+  '-include', 'config-cmd.hh',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+subdir('build-utils-meson/generate-header')
+
+nix_sources = files(
+  'add-to-store.cc',
+  'app.cc',
+  'build.cc',
+  'bundle.cc',
+  'cat.cc',
+  'config-check.cc',
+  'config.cc',
+  'copy.cc',
+  'derivation-add.cc',
+  'derivation-show.cc',
+  'derivation.cc',
+  'develop.cc',
+  'diff-closures.cc',
+  'dump-path.cc',
+  'edit.cc',
+  'env.cc',
+  'eval.cc',
+  'flake.cc',
+  'fmt.cc',
+  'hash.cc',
+  'log.cc',
+  'ls.cc',
+  'main.cc',
+  'make-content-addressed.cc',
+  'nar.cc',
+  'optimise-store.cc',
+  'path-from-hash-part.cc',
+  'path-info.cc',
+  'prefetch.cc',
+  'profile.cc',
+  'realisation.cc',
+  'registry.cc',
+  'repl.cc',
+  'run.cc',
+  'search.cc',
+  'sigs.cc',
+  'store-copy-log.cc',
+  'store-delete.cc',
+  'store-gc.cc',
+  'store-info.cc',
+  'store-repair.cc',
+  'store.cc',
+  'unix/daemon.cc',
+  'upgrade-nix.cc',
+  'verify.cc',
+  'why-depends.cc',
+)
+
+nix_sources += [
+  gen_header.process('doc/manual/generate-manpage.nix'),
+  gen_header.process('doc/manual/generate-settings.nix'),
+  gen_header.process('doc/manual/generate-store-info.nix'),
+  gen_header.process('doc/manual/utils.nix'),
+  gen_header.process('get-env.sh'),
+  gen_header.process('profiles.md'),
+  gen_header.process('help-stores.md'),
+]
+
+if host_machine.system() != 'windows'
+  nix_sources += files(
+    'unix/daemon.cc',
+  )
+endif
+
+# The rest of the subdirectories aren't separate components,
+# just source files in another directory, so we process them here.
+
+build_remote_sources = files(
+  'build-remote/build-remote.cc',
+)
+nix_build_sources = files(
+  'nix-build/nix-build.cc',
+)
+nix_channel_sources = files(
+  'nix-channel/nix-channel.cc',
+)
+unpack_channel_gen = gen_header.process('nix-channel/unpack-channel.nix')
+nix_collect_garbage_sources = files(
+  'nix-collect-garbage/nix-collect-garbage.cc',
+)
+nix_copy_closure_sources = files(
+  'nix-copy-closure/nix-copy-closure.cc',
+)
+nix_env_buildenv_gen = gen_header.process('nix-env/buildenv.nix')
+nix_env_sources = files(
+  'nix-env/nix-env.cc',
+  'nix-env/user-env.cc',
+)
+nix_instantiate_sources = files(
+  'nix-instantiate/nix-instantiate.cc',
+)
+nix_store_sources = files(
+  'nix-store/dotgraph.cc',
+  'nix-store/graphml.cc',
+  'nix-store/nix-store.cc',
+)
+
+# Hurray for Meson list flattening!
+sources = [
+  nix_sources,
+  build_remote_sources,
+  nix_build_sources,
+  nix_channel_sources,
+  unpack_channel_gen,
+  nix_collect_garbage_sources,
+  nix_copy_closure_sources,
+  nix_env_buildenv_gen,
+  nix_env_sources,
+  nix_instantiate_sources,
+  nix_store_sources,
+]
+
+include_dirs = [include_directories('.')]
+
+this_exe = executable(
+  meson.project_name(),
+  sources,
+  dependencies : deps_private_subproject + deps_private + deps_other,
+  include_directories : include_dirs,
+  link_args: linker_export_flags,
+  install : true,
+)
diff --git a/src/nix/nix-build b/src/nix/nix-build
new file mode 120000
index 000000000..2954d8ac7
--- /dev/null
+++ b/src/nix/nix-build
@@ -0,0 +1 @@
+../nix-build
\ No newline at end of file
diff --git a/src/nix/nix-channel b/src/nix/nix-channel
new file mode 120000
index 000000000..29b759473
--- /dev/null
+++ b/src/nix/nix-channel
@@ -0,0 +1 @@
+../nix-channel
\ No newline at end of file
diff --git a/src/nix/nix-collect-garbage b/src/nix/nix-collect-garbage
new file mode 120000
index 000000000..b037fc1b0
--- /dev/null
+++ b/src/nix/nix-collect-garbage
@@ -0,0 +1 @@
+../nix-collect-garbage
\ No newline at end of file
diff --git a/src/nix/nix-copy-closure b/src/nix/nix-copy-closure
new file mode 120000
index 000000000..9063c583a
--- /dev/null
+++ b/src/nix/nix-copy-closure
@@ -0,0 +1 @@
+../nix-copy-closure
\ No newline at end of file
diff --git a/src/nix/nix-env b/src/nix/nix-env
new file mode 120000
index 000000000..f2f19f580
--- /dev/null
+++ b/src/nix/nix-env
@@ -0,0 +1 @@
+../nix-env
\ No newline at end of file
diff --git a/src/nix/nix-instantiate b/src/nix/nix-instantiate
new file mode 120000
index 000000000..2d7502ffa
--- /dev/null
+++ b/src/nix/nix-instantiate
@@ -0,0 +1 @@
+../nix-instantiate
\ No newline at end of file
diff --git a/src/nix/nix-store b/src/nix/nix-store
new file mode 120000
index 000000000..e6efcac42
--- /dev/null
+++ b/src/nix/nix-store
@@ -0,0 +1 @@
+../nix-store/
\ No newline at end of file
diff --git a/src/nix/package.nix b/src/nix/package.nix
new file mode 100644
index 000000000..fe83c6969
--- /dev/null
+++ b/src/nix/package.nix
@@ -0,0 +1,129 @@
+{ lib
+, stdenv
+, mkMesonDerivation
+, releaseTools
+
+, meson
+, ninja
+, pkg-config
+
+, nix-store
+, nix-expr
+, nix-main
+, nix-cmd
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, version
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonDerivation (finalAttrs: {
+  pname = "nix";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions ([
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+
+    # Symbolic links to other dirs
+    ./build-remote
+    ./doc
+    ./nix-build
+    ./nix-channel
+    ./nix-collect-garbage
+    ./nix-copy-closure
+    ./nix-env
+    ./nix-instantiate
+    ./nix-store
+
+    # Doc nix files for --help
+    ../../doc/manual/generate-manpage.nix
+    ../../doc/manual/utils.nix
+    ../../doc/manual/generate-settings.nix
+    ../../doc/manual/generate-store-info.nix
+
+    # Other files to be included as string literals
+    ../nix-channel/unpack-channel.nix
+    ../nix-env/buildenv.nix
+    ./get-env.sh
+    ./help-stores.md
+    ../../doc/manual/src/store/types/index.md.in
+    ./profiles.md
+    ../../doc/manual/src/command-ref/files/profiles.md
+
+    # Files
+  ] ++ lib.concatMap
+    (dir: [
+      (fileset.fileFilter (file: file.hasExt "cc") dir)
+      (fileset.fileFilter (file: file.hasExt "hh") dir)
+      (fileset.fileFilter (file: file.hasExt "md") dir)
+    ])
+    [
+      ./.
+      ../build-remote
+      ../nix-build
+      ../nix-channel
+      ../nix-collect-garbage
+      ../nix-copy-closure
+      ../nix-env
+      ../nix-instantiate
+      ../nix-store
+    ]
+  );
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+  ];
+
+  buildInputs = [
+    nix-store
+    nix-expr
+    nix-main
+    nix-cmd
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  enableParallelBuilding = true;
+
+  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+
+  strictDeps = true;
+
+  hardeningDisable = lib.optional stdenv.hostPlatform.isStatic "pie";
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})
diff --git a/src/nix/profile.md b/src/nix/profile.md
index 9b2f86f4a..83a0b5f29 100644
--- a/src/nix/profile.md
+++ b/src/nix/profile.md
@@ -11,7 +11,7 @@ them to be rolled back easily.
 
 )""
 
-#include "generated-doc/files/profiles.md.gen.hh"
+#include "profiles.md.gen.hh"
 
 R""(
 
diff --git a/src/nix/profiles.md b/src/nix/profiles.md
new file mode 120000
index 000000000..c67a86194
--- /dev/null
+++ b/src/nix/profiles.md
@@ -0,0 +1 @@
+../../doc/manual/src/command-ref/files/profiles.md
\ No newline at end of file