Progress on Wine CI support, MinGW dev shell with Meson (#10975)

* Only build perl subproject on Linux

* Fix various Windows regressions

* Don't put the emulator hook in test builds

  We run the tests in a separate derivation. Only need it for the dev shell.

* Fix native dev shells

* Fix cross dev shells we don't know how to emulate

Co-authored-by: PoweredByPie <poweredbypie@users.noreply.github.com>
Co-authored-by: Joachim Schiele <js@lastlog.de>
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>

flake.nix

@@ -278,6 +278,7 @@
             in
               "-D${prefix}:${rest}";
           havePerl = stdenv.buildPlatform == stdenv.hostPlatform && stdenv.hostPlatform.isUnix;
+          ignoreCrossFile = flags: builtins.filter (flag: !(lib.strings.hasInfix "cross-file" flag)) flags;
         in {
           pname = "shell-for-" + attrs.pname;
 
@@ -309,10 +310,12 @@
           };
 
           mesonFlags =
-            map (transformFlag "libutil") pkgs.nixComponents.nix-util.mesonFlags
-            ++ map (transformFlag "libstore") pkgs.nixComponents.nix-store.mesonFlags
-            ++ map (transformFlag "libfetchers") pkgs.nixComponents.nix-fetchers.mesonFlags
-            ++ lib.optionals havePerl (map (transformFlag "perl") pkgs.nixComponents.nix-perl-bindings.mesonFlags)
+            map (transformFlag "libutil") (ignoreCrossFile pkgs.nixComponents.nix-util.mesonFlags)
+            ++ map (transformFlag "libstore") (ignoreCrossFile pkgs.nixComponents.nix-store.mesonFlags)
+            ++ map (transformFlag "libfetchers") (ignoreCrossFile pkgs.nixComponents.nix-fetchers.mesonFlags)
+            ++ lib.optionals havePerl (map (transformFlag "perl") (ignoreCrossFile pkgs.nixComponents.nix-perl-bindings.mesonFlags))
+            ++ map (transformFlag "libexpr") (ignoreCrossFile pkgs.nixComponents.nix-expr.mesonFlags)
+            ++ map (transformFlag "libcmd") (ignoreCrossFile pkgs.nixComponents.nix-cmd.mesonFlags)
             ;
 
           nativeBuildInputs = attrs.nativeBuildInputs or []
@@ -322,9 +325,16 @@
             ++ lib.optionals havePerl pkgs.nixComponents.nix-perl-bindings.nativeBuildInputs
             ++ pkgs.nixComponents.nix-internal-api-docs.nativeBuildInputs
             ++ pkgs.nixComponents.nix-external-api-docs.nativeBuildInputs
+            ++ lib.optional
+              (!stdenv.buildPlatform.canExecute stdenv.hostPlatform
+                 # Hack around https://github.com/nixos/nixpkgs/commit/bf7ad8cfbfa102a90463433e2c5027573b462479
+                 && !(stdenv.hostPlatform.isWindows && stdenv.buildPlatform.isDarwin)
+                 && stdenv.hostPlatform.emulatorAvailable pkgs.buildPackages
+                 && lib.meta.availableOn stdenv.buildPlatform (stdenv.hostPlatform.emulator pkgs.buildPackages))
+              pkgs.buildPackages.mesonEmulatorHook
             ++ [
               pkgs.buildPackages.cmake
-              pkgs.shellcheck
+              pkgs.buildPackages.shellcheck
               modular.pre-commit.settings.package
               (pkgs.writeScriptBin "pre-commit-hooks-install"
                 modular.pre-commit.settings.installationScript)

meson.build

@@ -29,7 +29,9 @@ subproject('libexpr-c')
 subproject('libmain-c')
 
 # Language Bindings
-subproject('perl')
+if not meson.is_cross_build()
+  subproject('perl')
+endif
 
 # Testing
 subproject('nix-util-test-support')

src/libexpr-c/nix_api_expr.cc

@@ -14,10 +14,10 @@
 #include "nix_api_util.h"
 #include "nix_api_util_internal.h"
 
-#ifdef HAVE_BOEHMGC
-#include <mutex>
-#define GC_INCLUDE_NEW 1
-#include "gc_cpp.h"
+#if HAVE_BOEHMGC
+#  include <mutex>
+#  define GC_INCLUDE_NEW 1
+#  include "gc_cpp.h"
 #endif
 
 nix_err nix_libexpr_init(nix_c_context * context)
@@ -131,7 +131,7 @@ void nix_state_free(EvalState * state)
     delete state;
 }
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 std::unordered_map<
     const void *,
     unsigned int,
@@ -207,7 +207,7 @@ nix_err nix_value_decref(nix_c_context * context, nix_value *x)
 
 void nix_gc_register_finalizer(void * obj, void * cd, void (*finalizer)(void * obj, void * cd))
 {
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
     GC_REGISTER_FINALIZER(obj, finalizer, cd, 0, 0);
 #endif
 }

src/libexpr-c/nix_api_external.cc

@@ -14,7 +14,7 @@
 
 #include <nlohmann/json.hpp>
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 # include "gc/gc.h"
 # define GC_INCLUDE_NEW 1
 # include "gc_cpp.h"
@@ -174,7 +174,7 @@ ExternalValue * nix_create_external_value(nix_c_context * context, NixCExternalV
         context->last_err_code = NIX_OK;
     try {
         auto ret = new
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
             (GC)
 #endif
                 NixCExternalValue(*desc, v);

src/libexpr-c/nix_api_value.cc

@@ -14,7 +14,7 @@
 #include "nix_api_value.h"
 #include "value/context.hh"
 
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
 #  include "gc/gc.h"
 #  define GC_INCLUDE_NEW 1
 #  include "gc_cpp.h"
@@ -131,7 +131,7 @@ PrimOp * nix_alloc_primop(
     try {
         using namespace std::placeholders;
         auto p = new
-#ifdef HAVE_BOEHMGC
+#if HAVE_BOEHMGC
             (GC)
 #endif
                 nix::PrimOp{

src/libstore/build/drv-output-substitution-goal.cc

@@ -62,7 +62,7 @@ Goal::Co DrvOutputSubstitutionGoal::init()
     #ifndef _WIN32
             outPipe->readSide.get()
     #else
-            &outPipe
+            &*outPipe
     #endif
         }, true, false);
 

src/libutil/file-system.cc

@@ -416,7 +416,11 @@ void deletePath(const fs::path & path)
 
 void createDir(const Path & path, mode_t mode)
 {
-    if (mkdir(path.c_str(), mode) == -1)
+    if (mkdir(path.c_str()
+#ifndef _WIN32
+                , mode
+#endif
+                ) == -1)
         throw SysError("creating directory '%1%'", path);
 }
 

src/libutil/fs-sink.cc

@@ -97,7 +97,7 @@ void RestoreSink::createRegularFile(const CanonPath & path, std::function<void(C
     RestoreRegularFile crf;
     crf.fd =
 #ifdef _WIN32
-        CreateFileW(path.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL)
+        CreateFileW(p.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL)
 #else
         open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY | O_CLOEXEC, 0666)
 #endif
@@ -145,7 +145,7 @@ void RestoreRegularFile::operator () (std::string_view data)
 void RestoreSink::createSymlink(const CanonPath & path, const std::string & target)
 {
     auto p = append(dstPath, path);
-    nix::createSymlink(target, p);
+    nix::createSymlink(target, p.string());
 }
 
 

src/nix/meson.build

@@ -88,12 +88,17 @@ nix_sources = files(
   'store-info.cc',
   'store-repair.cc',
   'store.cc',
-  'unix/daemon.cc',
   'upgrade-nix.cc',
   'verify.cc',
   'why-depends.cc',
 )
 
+if host_machine.system() != 'windows'
+  nix_sources += files(
+    'unix/daemon.cc',
+  )
+endif
+
 nix_sources += [
   gen_header.process('doc/manual/generate-manpage.nix'),
   gen_header.process('doc/manual/generate-settings.nix'),
@@ -104,12 +109,6 @@ nix_sources += [
   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.
 
@@ -146,9 +145,7 @@ nix_store_sources = files(
 # 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,
@@ -158,6 +155,13 @@ sources = [
   nix_store_sources,
 ]
 
+if host_machine.system() != 'windows'
+  sources += [
+    build_remote_sources,
+    nix_channel_sources,
+  ]
+endif
+
 include_dirs = [include_directories('.')]
 
 this_exe = executable(