fix external_project failing due to the drive letter in the path on Windows

data/test.schema.json

@@ -43,7 +43,9 @@
               "msvc",
               "gcc",
               "cygwin",
-              "!cygwin"
+              "!cygwin",
+              "windows",
+              "!windows"
             ]
           },
           "version": {

docs/markdown/Contributing.md

@@ -320,6 +320,8 @@ considered if the platform matches. The following values for
 | `gcc`      | Not `msvc`                                                           |
 | `cygwin`   | Matches when the platform is cygwin                                  |
 | `!cygwin`  | Not `cygwin`                                                         |
+| `windows`  | Matches when the platform is windows or cygwin                       |
+| `!windows` | Not `windows`                                                        |
 
 #### matrix
 

docs/markdown/snippets/external_project-cygpath-conversion.md

@@ -0,0 +1,7 @@
+## The external_project module uses the cygpath command to convert paths
+
+In previous versions, the external_project module on Windows used a Windows-style path (e.g., `C:/path/to/configure`) to execute the configure file, and a relative path from the drive root (e.g., `/path/to/prefix`) as the installation prefix.
+However, since configure scripts are typically intended to be run in a POSIX-like environment (MSYS2, Cygwin, or GitBash), these paths were incompatible with some configure scripts.
+
+The external_project module now uses the `cygpath` command to convert the configure command path and prefix to Unix-style paths (e.g., `/c/path/to/configure` for MSYS2 and `/cygdrive/c/path/to/configure` for Cygwin).
+If the `cygpath` command is not found in the PATH, it will fall back to the previous behavior.

mesonbuild/modules/external_project.py

@@ -6,6 +6,7 @@
 from pathlib import Path
 import os
 import shlex
+import shutil
 import subprocess
 import typing as T
 
@@ -19,7 +20,7 @@
 from ..interpreter.type_checking import ENV_KW, DEPENDS_KW
 from ..interpreterbase.decorators import ContainerTypeInfo, KwargInfo, typed_kwargs, typed_pos_args
 from ..mesonlib import (EnvironmentException, MesonException, Popen_safe, MachineChoice,
-                        get_variable_regex, do_replacement, join_args, relpath)
+                        get_variable_regex, do_replacement, join_args)
 from ..options import OptionKey
 
 if T.TYPE_CHECKING:
@@ -89,19 +90,29 @@ def __init__(self,
         self.includedir = Path(_i)
         self.name = self.src_dir.name
 
-        # On Windows if the prefix is "c:/foo" and DESTDIR is "c:/bar", `make`
-        # will install files into "c:/bar/c:/foo" which is an invalid path.
-        # Work around that issue by removing the drive from prefix.
-        if self.prefix.drive:
-            self.prefix = Path(relpath(self.prefix, self.prefix.drive))
+        self.prefix = self._cygpath_convert(self.prefix)
 
         # self.prefix is an absolute path, so we cannot append it to another path.
-        self.rel_prefix = Path(relpath(self.prefix, self.prefix.root))
+        # On Windows (where cygpath is not applied),
+        # if the prefix is "c:/foo" and DESTDIR is "c:/bar",
+        # `make` will install files into "c:/bar/c:/foo" which is an invalid path.
+        # This also removes the drive letter from the prefix to workaround the issue.
+        self.rel_prefix = self.prefix.relative_to(self.prefix.anchor)
 
         self._configure(state)
 
         self.targets = self._create_targets(extra_depends)
 
+    def _cygpath_convert(self, winpath: Path) -> Path:
+        # On Cygwin, MSYS2 and GitBash, the configure command and the prefix
+        # should be converted to unix style path like "/c/foo" by cygpath command,
+        # because the colon in the drive letter breaks many configure scripts.
+        # Do nothing on other environment where cygpath is not available.
+        if winpath.drive and shutil.which('cygpath'):
+            _p, o, _e = Popen_safe(['cygpath', '-u', winpath.as_posix()])
+            return Path(o.strip('\n'))
+        return winpath
+
     def _configure(self, state: 'ModuleState') -> None:
         if self.configure_command == 'waf':
             FeatureNew('Waf external project', '0.60.0').use(self.subproject, state.current_node)
@@ -116,6 +127,8 @@ def _configure(self, state: 'ModuleState') -> None:
             configure_path = Path(self.src_dir, self.configure_command)
             configure_prog = state.find_program(configure_path.as_posix())
             configure_cmd = configure_prog.get_command()
+            if len(configure_cmd) >= 2 and configure_cmd[-1] == configure_path.as_posix():
+                configure_cmd = configure_cmd[:-1] + [self._cygpath_convert(configure_path).as_posix()]
             workdir = self.build_dir
             self.make = state.find_program('make').get_command()
 

run_project_tests.py

@@ -158,6 +158,8 @@ def get_path(self, compiler: str, env: environment.Environment) -> T.Optional[Pa
             'gcc': canonical_compiler != 'msvc',
             'cygwin': env.machines.host.is_cygwin(),
             '!cygwin': not env.machines.host.is_cygwin(),
+            'windows': env.machines.host.is_windows() or env.machines.host.is_cygwin(),
+            '!windows': not (env.machines.host.is_windows() or env.machines.host.is_cygwin()),
         }.get(self.platform or '', True)
         if not matches:
             return None

test cases/common/230 external project/libfoo/configure

@@ -2,6 +2,23 @@
 
 srcdir=$(dirname "$0")
 
+# some configure scripts seem to iterate over srcdir and other paths
+# with for-loop using path_separator (most cases colon.)
+PATH_SEPARATOR=:
+(PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+(PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+  PATH_SEPARATOR=';'
+}
+IFS=$PATH_SEPARATOR
+for i in $srcdir
+do
+if [ "$i" != "$srcdir" ]
+then
+    echo "failed to extract $srcdir using path separator $PATH_SEPARATOR"
+    exit 1
+fi
+done
+
 for i in "$@"
 do
 case $i in

test cases/common/230 external project/libfoo/meson.build

@@ -17,6 +17,7 @@ p = mod.add_project('configure',
     '--libext=' + libext,
   ],
   depends: somelib,
+  verbose: true,
 )
 
 libfoo_dep = declare_dependency(link_with : somelib,

test cases/common/230 external project/meson.build

@@ -8,10 +8,6 @@ if not find_program('make', required : false).found()
   error('MESON_SKIP_TEST: make not found')
 endif
 
-if host_machine.system() == 'windows'
-  error('MESON_SKIP_TEST: The fake configure script is too dumb to work on Windows')
-endif
-
 if meson.is_cross_build()
   # CI uses PKG_CONFIG_SYSROOT_DIR which breaks -uninstalled.pc usage.
   error('MESON_SKIP_TEST: Cross build support is too limited for this test')

test cases/common/230 external project/test.json

@@ -1,7 +1,7 @@
 {
   "installed": [
-    { "type": "shared_lib",  "file": "usr/lib/foo", "platform": "!cygwin" },
-    { "type": "file",  "file": "usr/lib/libfoo.dll", "platform": "cygwin" },
+    { "type": "shared_lib",  "file": "usr/lib/foo", "platform": "!windows" },
+    { "type": "file",  "file": "usr/lib/libfoo.dll", "platform": "windows" },
     { "type": "file",  "file": "usr/include/libfoo.h" },
     { "type": "file", "file": "usr/lib/pkgconfig/somelib.pc" }
   ]