Fix executable as script on Windows

On Windows this would fail because of missing DLL:
```
mylib = library(...)
exe = executable(..., link_with: mylib)
meson.add_install_script(exe)
```

The reason is on Windows we cannot rely on rpath to find libraries from
build directory, they are searched in $PATH. We already have all that
mechanism in place for custom_target() using ExecutableSerialisation
class, so reuse it for install/dist/postconf scripts too.

This has bonus side effect to also use exe_wrapper for those scripts.

Fixes: #8187

13 files changed, 103 insertions, 81 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index b5e5cdf..caec761 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -22,9 +22,10 @@ import os
 import pickle
 import re
 import shlex
-import subprocess
 import textwrap
 import typing as T
+import hashlib
+import copy
 
 from .. import build
 from .. import dependencies
@@ -105,7 +106,7 @@ class InstallData:
         self.data: 'InstallType' = []
         self.po_package_name: str = ''
         self.po = []
-        self.install_scripts: T.List[build.RunScript] = []
+        self.install_scripts: T.List[ExecutableSerialisation] = []
         self.install_subdirs: 'InstallSubdirsType' = []
         self.mesonintrospect = mesonintrospect
         self.version = version
@@ -377,13 +378,11 @@ class Backend:
                 raise MesonException('Unknown data type in object list.')
         return obj_list
 
-    def as_meson_exe_cmdline(self, tname, exe, cmd_args, workdir=None,
-                             extra_bdeps=None, capture=None, force_serialize=False,
-                             env: T.Optional[build.EnvironmentVariables] = None):
-        '''
-        Serialize an executable for running with a generator or a custom target
-        '''
-        import hashlib
+    def get_executable_serialisation(self, cmd, workdir=None,
+                                     extra_bdeps=None, capture=None,
+                                     env: T.Optional[build.EnvironmentVariables] = None):
+        exe = cmd[0]
+        cmd_args = cmd[1:]
         if isinstance(exe, dependencies.ExternalProgram):
             exe_cmd = exe.get_command()
             exe_for_machine = exe.for_machine
@@ -403,11 +402,10 @@ class Backend:
         is_cross_built = not self.environment.machines.matches_build_machine(exe_for_machine)
         if is_cross_built and self.environment.need_exe_wrapper():
             exe_wrapper = self.environment.get_exe_wrapper()
-            if not exe_wrapper.found():
-                msg = 'The exe_wrapper {!r} defined in the cross file is ' \
-                      'needed by target {!r}, but was not found. Please ' \
-                      'check the command and/or add it to PATH.'
-                raise MesonException(msg.format(exe_wrapper.name, tname))
+            if not exe_wrapper or not exe_wrapper.found():
+                msg = 'An exe_wrapper is needed but was not found. Please define one ' \
+                      'in cross file and check the command and/or add it to PATH.'
+                raise MesonException(msg)
         else:
             if exe_cmd[0].endswith('.jar'):
                 exe_cmd = ['java', '-jar'] + exe_cmd
@@ -415,11 +413,24 @@ class Backend:
                 exe_cmd = ['mono'] + exe_cmd
             exe_wrapper = None
 
+        workdir = workdir or self.environment.get_build_dir()
+        return ExecutableSerialisation(exe_cmd + cmd_args, env,
+                                       exe_wrapper, workdir,
+                                       extra_paths, capture)
+
+    def as_meson_exe_cmdline(self, tname, exe, cmd_args, workdir=None,
+                             extra_bdeps=None, capture=None, force_serialize=False,
+                             env: T.Optional[build.EnvironmentVariables] = None):
+        '''
+        Serialize an executable for running with a generator or a custom target
+        '''
+        cmd = [exe] + cmd_args
+        es = self.get_executable_serialisation(cmd, workdir, extra_bdeps, capture, env)
         reasons = []
-        if extra_paths:
+        if es.extra_paths:
             reasons.append('to set PATH')
 
-        if exe_wrapper:
+        if es.exe_runner:
             reasons.append('to use exe_wrapper')
 
         if workdir:
@@ -440,10 +451,9 @@ class Backend:
             if not capture:
                 return None, ''
             return ((self.environment.get_build_command() +
-                    ['--internal', 'exe', '--capture', capture, '--'] + exe_cmd + cmd_args),
+                    ['--internal', 'exe', '--capture', capture, '--'] + es.cmd_args),
                     ', '.join(reasons))
 
-        workdir = workdir or self.environment.get_build_dir()
         if isinstance(exe, (dependencies.ExternalProgram,
                             build.BuildTarget, build.CustomTarget)):
             basename = exe.name
@@ -454,15 +464,12 @@ class Backend:
         # Take a digest of the cmd args, env, workdir, and capture. This avoids
         # collisions and also makes the name deterministic over regenerations
         # which avoids a rebuild by Ninja because the cmdline stays the same.
-        data = bytes(str(env) + str(cmd_args) + str(workdir) + str(capture),
+        data = bytes(str(env) + str(cmd_args) + str(es.workdir) + str(capture),
                      encoding='utf-8')
         digest = hashlib.sha1(data).hexdigest()
         scratch_file = 'meson_exe_{0}_{1}.dat'.format(basename, digest)
         exe_data = os.path.join(self.environment.get_scratch_dir(), scratch_file)
         with open(exe_data, 'wb') as f:
-            es = ExecutableSerialisation(exe_cmd + cmd_args, env,
-                                         exe_wrapper, workdir,
-                                         extra_paths, capture)
             pickle.dump(es, f)
         return (self.environment.get_build_command() + ['--internal', 'exe', '--unpickle', exe_data],
                 ', '.join(reasons))
@@ -1186,16 +1193,16 @@ class Backend:
         return inputs, outputs, cmd
 
     def run_postconf_scripts(self) -> None:
+        from ..scripts.meson_exe import run_exe
         env = {'MESON_SOURCE_ROOT': self.environment.get_source_dir(),
                'MESON_BUILD_ROOT': self.environment.get_build_dir(),
                'MESONINTROSPECT': ' '.join([shlex.quote(x) for x in self.environment.get_build_command() + ['introspect']]),
                }
-        child_env = os.environ.copy()
-        child_env.update(env)
 
         for s in self.build.postconf_scripts:
-            cmd = s['exe'] + s['args']
-            subprocess.check_call(cmd, env=child_env)
+            name = ' '.join(s.cmd_args)
+            mlog.log('Running postconf script {!r}'.format(name))
+            run_exe(s, env)
 
     def create_install_data(self) -> InstallData:
         strip_bin = self.environment.lookup_binary_entry(MachineChoice.HOST, 'strip')
@@ -1324,18 +1331,18 @@ class Backend:
                         d.targets.append(i)
 
     def generate_custom_install_script(self, d: InstallData) -> None:
-        result: T.List[build.RunScript] = []
+        result: T.List[ExecutableSerialisation] = []
         srcdir = self.environment.get_source_dir()
         builddir = self.environment.get_build_dir()
         for i in self.build.install_scripts:
-            exe = i['exe']
-            args = i['args']
             fixed_args = []
-            for a in args:
+            for a in i.cmd_args:
                 a = a.replace('@SOURCE_ROOT@', srcdir)
                 a = a.replace('@BUILD_ROOT@', builddir)
                 fixed_args.append(a)
-            result.append(build.RunScript(exe, fixed_args))
+            es = copy.copy(i)
+            es.cmd_args = fixed_args
+            result.append(es)
         d.install_scripts = result
 
     def generate_header_install(self, d: InstallData) -> None:
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 7b15bfe..32daf54 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -2609,14 +2609,6 @@ class Data:
         else:
             self.rename = rename
 
-class RunScript(dict):
-    def __init__(self, script, args):
-        super().__init__()
-        assert(isinstance(script, list))
-        assert(isinstance(args, list))
-        self['exe'] = script
-        self['args'] = args
-
 class TestSetup:
     def __init__(self, exe_wrapper: T.Optional[T.List[str]], gdb: bool,
                  timeout_multiplier: int, env: EnvironmentVariables):
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 8924a46..ceaa29a 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -34,7 +34,7 @@ from .interpreterbase import ObjectHolder, MesonVersionString
 from .interpreterbase import TYPE_var, TYPE_nkwargs
 from .modules import ModuleReturnValue, ExtensionModule
 from .cmake import CMakeInterpreter
-from .backend.backends import TestProtocol, Backend
+from .backend.backends import TestProtocol, Backend, ExecutableSerialisation
 
 from pathlib import Path, PurePath
 import os
@@ -1948,11 +1948,8 @@ class MesonMain(InterpreterObject):
                              })
 
     def _find_source_script(self, prog: T.Union[str, mesonlib.File, ExecutableHolder], args):
-        if isinstance(prog, ExecutableHolder):
-            prog_path = self.interpreter.backend.get_target_filename(prog.held_object)
-            return build.RunScript([prog_path], args)
-        elif isinstance(prog, ExternalProgramHolder):
-            return build.RunScript(prog.get_command(), args)
+        if isinstance(prog, (ExecutableHolder, ExternalProgramHolder)):
+            return self.interpreter.backend.get_executable_serialisation([unholder(prog)] + args)
         # Prefer scripts in the current source directory
         search_dir = os.path.join(self.interpreter.environment.source_dir,
                                   self.interpreter.subdir)
@@ -1970,7 +1967,7 @@ class MesonMain(InterpreterObject):
         else:
             m = 'Script or command {!r} not found or not executable'
             raise InterpreterException(m.format(prog))
-        return build.RunScript(found.get_command(), args)
+        return self.interpreter.backend.get_executable_serialisation([found] + args)
 
     def _process_script_args(
             self, name: str, args: T.List[T.Union[
@@ -2557,7 +2554,7 @@ class Interpreter(InterpreterBase):
             return GeneratedListHolder(item)
         elif isinstance(item, build.RunTarget):
             raise RuntimeError('This is not a pipe.')
-        elif isinstance(item, build.RunScript):
+        elif isinstance(item, ExecutableSerialisation):
             raise RuntimeError('Do not do this.')
         elif isinstance(item, build.Data):
             return DataHolder(item)
@@ -2584,7 +2581,7 @@ class Interpreter(InterpreterBase):
                 self.module_method_callback(v)
             elif isinstance(v, build.GeneratedList):
                 pass
-            elif isinstance(v, build.RunScript):
+            elif isinstance(v, ExecutableSerialisation):
                 self.build.install_scripts.append(v)
             elif isinstance(v, build.Data):
                 self.build.data.append(v)
diff --git a/mesonbuild/mdist.py b/mesonbuild/mdist.py
index 293eef4..4547b38 100644
--- a/mesonbuild/mdist.py
+++ b/mesonbuild/mdist.py
@@ -26,6 +26,7 @@ from mesonbuild.environment import detect_ninja
 from mesonbuild.mesonlib import windows_proof_rmtree, MesonException, quiet_git
 from mesonbuild.wrap import wrap
 from mesonbuild import mlog, build
+from .scripts.meson_exe import run_exe
 
 archive_choices = ['gztar', 'xztar', 'zip']
 archive_extension = {'gztar': '.tar.gz',
@@ -79,17 +80,15 @@ def process_submodules(dirname):
 
 def run_dist_scripts(src_root, bld_root, dist_root, dist_scripts):
     assert(os.path.isabs(dist_root))
-    env = os.environ.copy()
+    env = {}
     env['MESON_DIST_ROOT'] = dist_root
     env['MESON_SOURCE_ROOT'] = src_root
     env['MESON_BUILD_ROOT'] = bld_root
     for d in dist_scripts:
-        script = d['exe']
-        args = d['args']
-        name = ' '.join(script + args)
+        name = ' '.join(d.cmd_args)
         print('Running custom dist script {!r}'.format(name))
         try:
-            rc = subprocess.call(script + args, env=env)
+            rc = run_exe(d, env)
             if rc != 0:
                 sys.exit('Dist script errored out')
         except OSError:
diff --git a/mesonbuild/minstall.py b/mesonbuild/minstall.py
index 3e425eb..98608c7 100644
--- a/mesonbuild/minstall.py
+++ b/mesonbuild/minstall.py
@@ -30,6 +30,7 @@ from .coredata import major_versions_differ, MesonVersionMismatchException
 from .coredata import version as coredata_version
 from .mesonlib import is_windows, Popen_safe
 from .scripts import depfixer, destdir_join
+from .scripts.meson_exe import run_exe
 try:
     from __main__ import __file__ as main_file
 except ImportError:
@@ -485,17 +486,12 @@ class Installer:
         if self.options.quiet:
             env['MESON_INSTALL_QUIET'] = '1'
 
-        child_env = os.environ.copy()
-        child_env.update(env)
-
         for i in d.install_scripts:
             self.did_install_something = True  # Custom script must report itself if it does nothing.
-            script = i['exe']
-            args = i['args']
-            name = ' '.join(script + args)
+            name = ' '.join(i.cmd_args)
             self.log('Running custom install script {!r}'.format(name))
             try:
-                rc = subprocess.call(script + args, env=child_env)
+                rc = run_exe(i, env)
             except OSError:
                 print('FAILED: install script \'{}\' could not be run, stopped'.format(name))
                 # POSIX shells return 127 when a command could not be found
diff --git a/mesonbuild/modules/gnome.py b/mesonbuild/modules/gnome.py
index 5cad9f5..f564eb4 100644
--- a/mesonbuild/modules/gnome.py
+++ b/mesonbuild/modules/gnome.py
@@ -899,7 +899,7 @@ class GnomeModule(ExtensionModule):
             args.append('--media=' + '@@'.join(media))
         if langs:
             args.append('--langs=' + '@@'.join(langs))
-        inscript = build.RunScript(script, args)
+        inscript = state.backend.get_executable_serialisation(script + args)
 
         potargs = state.environment.get_build_command() + [
             '--internal', 'yelphelper', 'pot',
@@ -1051,7 +1051,7 @@ class GnomeModule(ExtensionModule):
             self.interpreter.add_test(state.current_node, check_args, check_kwargs, True)
         res = [custom_target, alias_target]
         if kwargs.get('install', True):
-            res.append(build.RunScript(command, args))
+            res.append(state.backend.get_executable_serialisation(command + args))
         return ModuleReturnValue(custom_target, res)
 
     def _get_build_args(self, kwargs, state, depends):
diff --git a/mesonbuild/modules/hotdoc.py b/mesonbuild/modules/hotdoc.py
index 931db12..eda411c 100644
--- a/mesonbuild/modules/hotdoc.py
+++ b/mesonbuild/modules/hotdoc.py
@@ -350,7 +350,7 @@ class HotdocTargetBuilder:
 
         install_script = None
         if install is True:
-            install_script = HotdocRunScript(self.build_command, [
+            install_script = self.state.backend.get_executable_serialisation(self.build_command + [
                 "--internal", "hotdoc",
                 "--install", os.path.join(fullname, 'html'),
                 '--name', self.name,
@@ -391,11 +391,6 @@ class HotdocTarget(build.CustomTarget):
         return res
 
 
-class HotdocRunScript(build.RunScript):
-    def __init__(self, script, args):
-        super().__init__(script, args)
-
-
 class HotDocModule(ExtensionModule):
     @FeatureNew('Hotdoc Module', '0.48.0')
     def __init__(self, interpreter):
diff --git a/mesonbuild/modules/i18n.py b/mesonbuild/modules/i18n.py
index d48f83b..ae24e6e 100644
--- a/mesonbuild/modules/i18n.py
+++ b/mesonbuild/modules/i18n.py
@@ -180,7 +180,7 @@ class I18nModule(ExtensionModule):
                     pkg_arg]
             if lang_arg:
                 args.append(lang_arg)
-            iscript = build.RunScript(script, args)
+            iscript = state.backend.get_executable_serialisation(script + args)
             targets.append(iscript)
 
         return ModuleReturnValue(None, targets)
diff --git a/mesonbuild/scripts/meson_exe.py b/mesonbuild/scripts/meson_exe.py
index 751d39b..620f579 100644
--- a/mesonbuild/scripts/meson_exe.py
+++ b/mesonbuild/scripts/meson_exe.py
@@ -30,7 +30,7 @@ def buildparser() -> argparse.ArgumentParser:
     parser.add_argument('--capture')
     return parser
 
-def run_exe(exe: ExecutableSerialisation) -> int:
+def run_exe(exe: ExecutableSerialisation, extra_env: T.Optional[dict] = None) -> int:
     if exe.exe_runner:
         if not exe.exe_runner.found():
             raise AssertionError('BUG: Can\'t run cross-compiled exe {!r} with not-found '
@@ -39,6 +39,8 @@ def run_exe(exe: ExecutableSerialisation) -> int:
     else:
         cmd_args = exe.cmd_args
     child_env = os.environ.copy()
+    if extra_env:
+        child_env.update(extra_env)
     if exe.env:
         child_env = exe.env.get_env(child_env)
     if exe.extra_paths:
@@ -56,14 +58,21 @@ def run_exe(exe: ExecutableSerialisation) -> int:
                          stderr=subprocess.PIPE)
     stdout, stderr = p.communicate()
 
-    if exe.pickled and p.returncode != 0:
-        print('while executing {!r}'.format(cmd_args))
-
     if p.returncode == 0xc0000135:
         # STATUS_DLL_NOT_FOUND on Windows indicating a common problem that is otherwise hard to diagnose
         raise FileNotFoundError('due to missing DLLs')
 
-    if exe.capture and p.returncode == 0:
+    if p.returncode != 0:
+        if exe.pickled:
+            print('while executing {!r}'.format(cmd_args))
+        if not exe.capture:
+            print('--- stdout ---')
+            print(stdout.decode())
+        print('--- stderr ---')
+        print(stderr.decode())
+        return p.returncode
+
+    if exe.capture:
         skip_write = False
         try:
             with open(exe.capture, 'rb') as cur:
@@ -73,11 +82,8 @@ def run_exe(exe: ExecutableSerialisation) -> int:
         if not skip_write:
             with open(exe.capture, 'wb') as output:
                 output.write(stdout)
-    else:
-        sys.stdout.buffer.write(stdout)
-    if stderr:
-        sys.stderr.buffer.write(stderr)
-    return p.returncode
+
+    return 0
 
 def run(args: T.List[str]) -> int:
     global options
diff --git a/test cases/common/54 install script/meson.build b/test cases/common/54 install script/meson.build
index eab95ab..24d5dc8 100644
--- a/test cases/common/54 install script/meson.build
+++ b/test cases/common/54 install script/meson.build
@@ -1,6 +1,5 @@
 project('custom install script', 'c')
 
-executable('prog', 'prog.c', install : true)
 meson.add_install_script('myinstall.py', 'diiba/daaba', 'file.dat')
 meson.add_install_script('myinstall.py', 'this/should', 'also-work.dat')
 
@@ -33,3 +32,14 @@ installer = configure_file(
 )
 
 meson.add_install_script(installer, 'otherdir', afile, '--mode=copy')
+
+# This executable links on a library built in src/ directory. On Windows this
+# means meson must add src/ into $PATH to find the DLL when running it as
+# install script.
+myexe = executable('prog', 'prog.c',
+  link_with: mylib,
+  install : true,
+)
+if meson.can_run_host_binaries()
+  meson.add_install_script(myexe)
+endif
diff --git a/test cases/common/54 install script/prog.c b/test cases/common/54 install script/prog.c
index 3bbf08e..85f8df9 100644
--- a/test cases/common/54 install script/prog.c
+++ b/test cases/common/54 install script/prog.c
@@ -1,6 +1,14 @@
 #include<stdio.h>
 
+#ifdef _WIN32
+  #define DO_IMPORT __declspec(dllimport)
+#else
+  #define DO_IMPORT
+#endif
+
+DO_IMPORT int foo(void);
+
 int main(void) {
     printf("This is text.\n");
-    return 0;
+    return foo();
 }
diff --git a/test cases/common/54 install script/src/foo.c b/test cases/common/54 install script/src/foo.c
new file mode 100644
index 0000000..46cb845
--- /dev/null
+++ b/test cases/common/54 install script/src/foo.c
@@ -0,0 +1,10 @@
+#ifdef _WIN32
+  #define DO_EXPORT __declspec(dllexport)
+#else
+  #define DO_EXPORT
+#endif
+
+DO_EXPORT int foo(void)
+{
+  return 0;
+}
diff --git a/test cases/common/54 install script/src/meson.build b/test cases/common/54 install script/src/meson.build
index 123fe18..72de346 100644
--- a/test cases/common/54 install script/src/meson.build
+++ b/test cases/common/54 install script/src/meson.build
@@ -1,3 +1,5 @@
 meson.add_install_script('myinstall.py', 'this/does', 'something-different.dat')
 
 afile = files('a file.txt')
+
+mylib = shared_library('mylib', 'foo.c')