Merge pull request #10990 from xclaesse/devenv

devenv: various improvements

8 files changed, 84 insertions, 63 deletions

diff --git a/docs/markdown/Commands.md b/docs/markdown/Commands.md
index c3284611a..4a00c4f4c 100644
--- a/docs/markdown/Commands.md
+++ b/docs/markdown/Commands.md
@@ -345,6 +345,8 @@ These variables are set in environment in addition to those set using [[meson.ad
   schemas is compiled. This is automatically set when using `gnome.compile_schemas()`.
   Note that this requires GLib >= 2.64 when `gnome.compile_schemas()` is used in
   more than one directory.
+- `QEMU_LD_PREFIX` *Since 1.0.0* is set to the `sys_root` value from cross file
+  when cross compiling and that property is defined.
 
 Since *Since 0.62.0* if bash-completion scripts are being installed and the
 shell is bash, they will be automatically sourced.
diff --git a/docs/markdown/snippets/devenv.md b/docs/markdown/snippets/devenv.md
new file mode 100644
index 000000000..d8a38bacc
--- /dev/null
+++ b/docs/markdown/snippets/devenv.md
@@ -0,0 +1,15 @@
+## Developer environment improvements
+
+When cross compiling, the developer environment now sets all environment
+variables for the HOST machine. It now also sets `QEMU_LD_PREFIX` to the
+`sys_root` value from cross file if property is defined. That means that cross
+compiled executables can often be run transparently on the build machine, for
+example when cross compiling for aarch64 linux from x86_64 linux.
+
+A new argument `--workdir` has been added, by default it is set to build
+directory. For example, `meson devenv -C builddir --workdir .` can be used to
+remain in the current dir (often source dir) instead.
+
+`--dump` now prints shell commands like `FOO="/prepend/path:$FOO:/append/path"`,
+using the litteral `$FOO` instead of current value of `FOO` from environment.
+This makes easier to evaluate those expressions in a different environment.
diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 747d80edd..27004f870 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -1108,10 +1108,7 @@ class Backend:
                         break
 
             is_cross = self.environment.is_cross_build(test_for_machine)
-            if is_cross and self.environment.need_exe_wrapper():
-                exe_wrapper = self.environment.get_exe_wrapper()
-            else:
-                exe_wrapper = None
+            exe_wrapper = self.environment.get_exe_wrapper()
             machine = self.environment.machines[exe.for_machine]
             if machine.is_windows() or machine.is_cygwin():
                 extra_bdeps: T.List[T.Union[build.BuildTarget, build.CustomTarget]] = []
@@ -1850,14 +1847,12 @@ class Backend:
         env = build.EnvironmentVariables()
         extra_paths = set()
         library_paths = set()
+        build_machine = self.environment.machines[MachineChoice.BUILD]
         host_machine = self.environment.machines[MachineChoice.HOST]
-        need_exe_wrapper = self.environment.need_exe_wrapper()
-        need_wine = need_exe_wrapper and host_machine.is_windows()
+        need_wine = not build_machine.is_windows() and host_machine.is_windows()
         for t in self.build.get_targets().values():
-            cross_built = not self.environment.machines.matches_build_machine(t.for_machine)
-            can_run = not cross_built or not need_exe_wrapper or need_wine
             in_default_dir = t.should_install() and not t.get_install_dir()[2]
-            if not can_run or not in_default_dir:
+            if t.for_machine != MachineChoice.HOST or not in_default_dir:
                 continue
             tdir = os.path.join(self.environment.get_build_dir(), self.get_target_dir(t))
             if isinstance(t, build.Executable):
@@ -1874,18 +1869,23 @@ class Backend:
                 # LD_LIBRARY_PATH. This allows running system applications using
                 # that library.
                 library_paths.add(tdir)
+        if need_wine:
+            # Executable paths should be in both PATH and WINEPATH.
+            # - Having them in PATH makes bash completion find it,
+            #   and make running "foo.exe" find it when wine-binfmt is installed.
+            # - Having them in WINEPATH makes "wine foo.exe" find it.
+            library_paths.update(extra_paths)
         if library_paths:
-            if host_machine.is_windows() or host_machine.is_cygwin():
+            if need_wine:
+                env.prepend('WINEPATH', list(library_paths), separator=';')
+            elif host_machine.is_windows() or host_machine.is_cygwin():
                 extra_paths.update(library_paths)
             elif host_machine.is_darwin():
                 env.prepend('DYLD_LIBRARY_PATH', list(library_paths))
             else:
                 env.prepend('LD_LIBRARY_PATH', list(library_paths))
         if extra_paths:
-            if need_wine:
-                env.prepend('WINEPATH', list(extra_paths), separator=';')
-            else:
-                env.prepend('PATH', list(extra_paths))
+            env.prepend('PATH', list(extra_paths))
         return env
 
     def compiler_to_generator(self, target: build.BuildTarget,
diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index a9df75ee3..9691cf126 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -25,9 +25,7 @@ from .mesonlib import (
     search_version, MesonBugException
 )
 from . import mlog
-from .programs import (
-    ExternalProgram, EmptyExternalProgram
-)
+from .programs import ExternalProgram
 
 from .envconfig import (
     BinaryTable, MachineInfo, Properties, known_cpu_families, CMakeVariables,
@@ -852,7 +850,7 @@ class Environment:
             return value
         return not machine_info_can_run(self.machines[for_machine])
 
-    def get_exe_wrapper(self) -> ExternalProgram:
+    def get_exe_wrapper(self) -> T.Optional[ExternalProgram]:
         if not self.need_exe_wrapper():
-            return EmptyExternalProgram()
+            return None
         return self.exe_wrapper
diff --git a/mesonbuild/mdevenv.py b/mesonbuild/mdevenv.py
index b75d18b83..b25d73b81 100644
--- a/mesonbuild/mdevenv.py
+++ b/mesonbuild/mdevenv.py
@@ -6,7 +6,8 @@ import itertools
 
 from pathlib import Path
 from . import build, minstall, dependencies
-from .mesonlib import MesonException, RealPathAction, is_windows, setup_vsenv, OptionKey, quote_arg, get_wine_shortpath
+from .mesonlib import (MesonException, is_windows, setup_vsenv, OptionKey,
+                       get_wine_shortpath, MachineChoice)
 from . import mlog
 
 import typing as T
@@ -16,8 +17,10 @@ if T.TYPE_CHECKING:
 POWERSHELL_EXES = {'pwsh.exe', 'powershell.exe'}
 
 def add_arguments(parser: argparse.ArgumentParser) -> None:
-    parser.add_argument('-C', dest='wd', action=RealPathAction,
-                        help='Directory to cd into before running')
+    parser.add_argument('-C', dest='builddir', type=Path, default='.',
+                        help='Path to build directory')
+    parser.add_argument('--workdir', '-w', type=Path, default=None,
+                        help='Directory to cd into before running (default: builddir, Since 1.0.0)')
     parser.add_argument('--dump', action='store_true',
                         help='Only print required environment (Since 0.62.0)')
     parser.add_argument('devcmd', nargs=argparse.REMAINDER, metavar='command',
@@ -45,15 +48,19 @@ def reduce_winepath(env: T.Dict[str, str]) -> None:
     env['WINEPATH'] = get_wine_shortpath([winecmd], winepath.split(';'))
     mlog.log('Meson detected wine and has set WINEPATH accordingly')
 
-def get_env(b: build.Build) -> T.Tuple[T.Dict[str, str], T.Set[str]]:
+def get_env(b: build.Build, dump: bool) -> T.Tuple[T.Dict[str, str], T.Set[str]]:
     extra_env = build.EnvironmentVariables()
     extra_env.set('MESON_DEVENV', ['1'])
     extra_env.set('MESON_PROJECT_NAME', [b.project_name])
 
-    env = os.environ.copy()
+    sysroot = b.environment.properties[MachineChoice.HOST].get_sys_root()
+    if sysroot:
+        extra_env.set('QEMU_LD_PREFIX', [sysroot])
+
+    env = {} if dump else os.environ.copy()
     varnames = set()
     for i in itertools.chain(b.devenv, {extra_env}):
-        env = i.get_env(env)
+        env = i.get_env(env, dump)
         varnames |= i.get_names()
 
     reduce_winepath(env)
@@ -90,7 +97,7 @@ def add_gdb_auto_load(autoload_path: Path, gdb_helper: str, fname: Path) -> None
     except (FileExistsError, shutil.SameFileError):
         pass
 
-def write_gdb_script(privatedir: Path, install_data: 'InstallData') -> None:
+def write_gdb_script(privatedir: Path, install_data: 'InstallData', workdir: Path) -> None:
     if not shutil.which('gdb'):
         return
     bdir = privatedir.parent
@@ -120,26 +127,44 @@ def write_gdb_script(privatedir: Path, install_data: 'InstallData') -> None:
             gdbinit_path.write_text(gdbinit_line, encoding='utf-8')
             first_time = True
         if first_time:
-            mlog.log('Meson detected GDB helpers and added config in', mlog.bold(str(gdbinit_path)))
+            gdbinit_path = gdbinit_path.resolve()
+            workdir_path = workdir.resolve()
+            rel_path = gdbinit_path.relative_to(workdir_path)
+            mlog.log('Meson detected GDB helpers and added config in', mlog.bold(str(rel_path)))
+            mlog.log('To load it automatically you might need to:')
+            mlog.log(' - Add', mlog.bold(f'add-auto-load-safe-path {gdbinit_path.parent}'),
+                     'in', mlog.bold('~/.gdbinit'))
+            if gdbinit_path.parent != workdir_path:
+                mlog.log(' - Change current workdir to', mlog.bold(str(rel_path.parent)),
+                         'or use', mlog.bold(f'--init-command {rel_path}'))
 
 def run(options: argparse.Namespace) -> int:
-    privatedir = Path(options.wd) / 'meson-private'
+    privatedir = Path(options.builddir) / 'meson-private'
     buildfile = privatedir / 'build.dat'
     if not buildfile.is_file():
-        raise MesonException(f'Directory {options.wd!r} does not seem to be a Meson build directory.')
-    b = build.load(options.wd)
+        raise MesonException(f'Directory {options.builddir!r} does not seem to be a Meson build directory.')
+    b = build.load(options.builddir)
+    workdir = options.workdir or options.builddir
 
-    devenv, varnames = get_env(b)
+    devenv, varnames = get_env(b, options.dump)
     if options.dump:
         if options.devcmd:
             raise MesonException('--dump option does not allow running other command.')
         for name in varnames:
-            print(f'{name}={quote_arg(devenv[name])}')
+            print(f'{name}="{devenv[name]}"')
             print(f'export {name}')
         return 0
 
+    if b.environment.need_exe_wrapper():
+        m = 'An executable wrapper could be required'
+        exe_wrapper = b.environment.get_exe_wrapper()
+        if exe_wrapper:
+            cmd = ' '.join(exe_wrapper.get_command())
+            m += f': {cmd}'
+        mlog.log(m)
+
     install_data = minstall.load_install_data(str(privatedir / 'install.dat'))
-    write_gdb_script(privatedir, install_data)
+    write_gdb_script(privatedir, install_data, workdir)
 
     setup_vsenv(b.need_vsenv)
 
@@ -182,7 +207,7 @@ def run(options: argparse.Namespace) -> int:
     try:
         return subprocess.call(args, close_fds=False,
                                env=devenv,
-                               cwd=options.wd)
+                               cwd=workdir)
     except subprocess.CalledProcessError as e:
         return e.returncode
     except FileNotFoundError:
diff --git a/mesonbuild/modules/gnome.py b/mesonbuild/modules/gnome.py
index 1d5e746b2..d0d7dbf89 100644
--- a/mesonbuild/modules/gnome.py
+++ b/mesonbuild/modules/gnome.py
@@ -39,7 +39,7 @@ from ..interpreterbase.decorators import typed_pos_args
 from ..mesonlib import (
     MachineChoice, MesonException, OrderedSet, Popen_safe, join_args,
 )
-from ..programs import OverrideProgram, EmptyExternalProgram
+from ..programs import OverrideProgram
 from ..scripts.gettext import read_linguas
 
 if T.TYPE_CHECKING:
@@ -1464,9 +1464,8 @@ class GnomeModule(ExtensionModule):
             t_args.append(f'--{program_name}={path}')
         if namespace:
             t_args.append('--namespace=' + namespace)
-        # if not need_exe_wrapper, we get an EmptyExternalProgram. If none provided, we get NoneType
         exe_wrapper = state.environment.get_exe_wrapper()
-        if not isinstance(exe_wrapper, (NoneType, EmptyExternalProgram)):
+        if exe_wrapper:
             t_args.append('--run=' + ' '.join(exe_wrapper.get_command()))
         t_args.append(f'--htmlargs={"@@".join(kwargs["html_args"])}')
         t_args.append(f'--scanargs={"@@".join(kwargs["scan_args"])}')
diff --git a/mesonbuild/programs.py b/mesonbuild/programs.py
index 458fabac9..1d616aaf9 100644
--- a/mesonbuild/programs.py
+++ b/mesonbuild/programs.py
@@ -345,25 +345,6 @@ class NonExistingExternalProgram(ExternalProgram):  # lgtm [py/missing-call-to-i
         return False
 
 
-class EmptyExternalProgram(ExternalProgram):  # lgtm [py/missing-call-to-init]
-    '''
-    A program object that returns an empty list of commands. Used for cases
-    such as a cross file exe_wrapper to represent that it's not required.
-    '''
-
-    def __init__(self) -> None:
-        self.name = None
-        self.command = []
-        self.path = None
-
-    def __repr__(self) -> str:
-        r = '<{} {!r} -> {!r}>'
-        return r.format(self.__class__.__name__, self.name, self.command)
-
-    def found(self) -> bool:
-        return True
-
-
 class OverrideProgram(ExternalProgram):
 
     """A script overriding a program."""
diff --git a/mesonbuild/utils/core.py b/mesonbuild/utils/core.py
index ed413cace..5450cdc29 100644
--- a/mesonbuild/utils/core.py
+++ b/mesonbuild/utils/core.py
@@ -119,23 +119,24 @@ class EnvironmentVariables(HoldableObject):
         self.envvars.append((self._prepend, name, values, separator))
 
     @staticmethod
-    def _set(env: T.Dict[str, str], name: str, values: T.List[str], separator: str) -> str:
+    def _set(env: T.Dict[str, str], name: str, values: T.List[str], separator: str, default_value: T.Optional[str]) -> str:
         return separator.join(values)
 
     @staticmethod
-    def _append(env: T.Dict[str, str], name: str, values: T.List[str], separator: str) -> str:
-        curr = env.get(name)
+    def _append(env: T.Dict[str, str], name: str, values: T.List[str], separator: str, default_value: T.Optional[str]) -> str:
+        curr = env.get(name, default_value)
         return separator.join(values if curr is None else [curr] + values)
 
     @staticmethod
-    def _prepend(env: T.Dict[str, str], name: str, values: T.List[str], separator: str) -> str:
-        curr = env.get(name)
+    def _prepend(env: T.Dict[str, str], name: str, values: T.List[str], separator: str, default_value: T.Optional[str]) -> str:
+        curr = env.get(name, default_value)
         return separator.join(values if curr is None else values + [curr])
 
-    def get_env(self, full_env: T.MutableMapping[str, str]) -> T.Dict[str, str]:
+    def get_env(self, full_env: T.MutableMapping[str, str], dump: bool = False) -> T.Dict[str, str]:
         env = full_env.copy()
         for method, name, values, separator in self.envvars:
-            env[name] = method(env, name, values, separator)
+            default_value = f'${name}' if dump else None
+            env[name] = method(env, name, values, separator, default_value)
         return env