Build old (pre-v145) PlatformToolset-pinned .vcxproj files

vintner only ever downloads one compiler generation, but real-world
.vcxproj files are pinned to whichever PlatformToolset they were last
saved under - v142 (VS2019) for anything not actively maintained is
extremely common. MSBuild checks toolset "installed-ness" (MSB8020) by
testing whether MSBuild/Microsoft/VC/v<schema>/Platforms/<arch>/
PlatformToolsets/<toolset>/ exists on disk - a plain file lookup our
downloaded MSBuild package only satisfies for the exact generation it
shipped. `install` now symlinks every historical numeric PlatformToolset
name (v90 through v143) onto whichever real toolset directory is
actually present, so any of them resolves transparently; Toolset.props/
.targets don't hardcode a version number, so aliasing is correct, not
just a workaround.

Three more MSBuild property/environment issues came with it, all found
building a real years-old project against the one modern toolchain
vintner installs:

- VCInstallDir_<N>/VCToolsInstallDir_<N> needed a third numbering
  source (PlatformToolset short names from Microsoft.VCToolsVersion.
  v<N>.default.props) alongside the existing MSBuild schema-version and
  known-toolset lists, so the env-var-driven half of toolset resolution
  covers the same names the on-disk alias does.
- VCToolsVersion must be a real version string: left unset, it falls
  back to a literal placeholder that then hits an unconditional
  version-string comparison elsewhere in Microsoft.CppBuild.targets
  (MSB4184). Setting it to the real installed version in turn requires
  CheckMSVCComponents=false, since CheckVCToolsetVersion (MSB8052)
  otherwise rejects an aliased PlatformToolset whenever its numeric
  generation doesn't match VCToolsVersion's - exactly the case aliasing
  creates on purpose. Everything else CheckMSVCComponents gates is
  diagnostic-only (MFC/ATL/Spectre presence warnings), so disabling it
  costs nothing else.
- WindowsTargetPlatformVersion needed to become an explicit /p: global
  property on the msbuild command line, not just an env var: legacy
  .vcxproj files commonly hardcode this in a PropertyGroup, and an
  explicit project assignment always wins over an inherited environment
  variable of the same name. A command-line global property is the one
  thing a project file can't override. Only injected when the caller
  hasn't already pinned it themselves.

internal/install/install.go

@@ -62,6 +62,10 @@ func Install(dest, selfBinary string) error {
 		return err
 	}
 
+	if err := aliasPlatformToolsets(dest); err != nil {
+		return err
+	}
+
 	includeDir := filepath.Join(msvcDir, "include")
 	if err := Lowercase(includeDir, LowercaseOptions{Symlink: true}); err != nil {
 		return fmt.Errorf("lowercasing %s: %w", includeDir, err)

internal/install/platformtoolsets.go

@@ -0,0 +1,92 @@
+package install
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+
+	"github.com/Cheviiot/vintner/internal/wineenv"
+)
+
+var rePlatformToolsetDir = regexp.MustCompile(`^v(\d+)$`)
+
+// aliasPlatformToolsets makes every historical PlatformToolset name in
+// wineenv.KnownPlatformToolsets resolve to the one compiler `download`
+// actually fetched.
+//
+// MSBuild decides whether a PlatformToolset is "installed" at all - the
+// check behind MSB8020 - by testing whether
+// MSBuild/Microsoft/VC/v<schema>/Platforms/<arch>/PlatformToolsets/<toolset>/
+// exists on disk (Microsoft.Cpp.props, via
+// ToolLocationHelper.FindRootFolderWhereAllFilesExist). That's a plain file
+// lookup, not influenced by any environment variable - unlike the later,
+// env-var-driven VCInstallDir_<N> checks internal/wrapper's msbuildEnv
+// covers, this one needs the actual directory to exist under dest.
+// Microsoft's own downloaded MSBuild package only ships a PlatformToolsets
+// entry for the exact generation matching the fetched compiler, so any
+// project pinned to an older PlatformToolset (v142 for a project last saved
+// under VS2019, say) fails this check outright even though the one real
+// toolchain installed could easily build it.
+//
+// Toolset.props/Toolset.targets don't hardcode a version number (they just
+// import version-agnostic files like Microsoft.Cpp.MSVC.Toolset.<arch>.props),
+// so a symlink under any other historical name is a correct, transparent
+// alias rather than a divergent copy.
+func aliasPlatformToolsets(dest string) error {
+	schemaDirs, err := filepath.Glob(filepath.Join(dest, "MSBuild", "Microsoft", "VC", "v*"))
+	if err != nil {
+		return err
+	}
+	for _, schemaDir := range schemaDirs {
+		archDirs, err := filepath.Glob(filepath.Join(schemaDir, "Platforms", "*", "PlatformToolsets"))
+		if err != nil {
+			return err
+		}
+		for _, toolsetsDir := range archDirs {
+			if err := aliasOneDir(toolsetsDir); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// aliasOneDir symlinks every name in wineenv.KnownPlatformToolsets that
+// doesn't already exist in toolsetsDir onto whichever real v<N> toolset
+// subdirectory is actually present there.
+func aliasOneDir(toolsetsDir string) error {
+	entries, err := os.ReadDir(toolsetsDir)
+	if err != nil {
+		return err
+	}
+	var real string
+	for _, e := range entries {
+		if !e.IsDir() {
+			continue
+		}
+		if rePlatformToolsetDir.MatchString(e.Name()) {
+			real = e.Name()
+			break
+		}
+	}
+	if real == "" {
+		// Nothing numeric here (e.g. only the WindowsKernelModeDriver10.0-style
+		// WDK toolsets) - nothing to alias.
+		return nil
+	}
+
+	for _, n := range wineenv.KnownPlatformToolsets {
+		alias := "v" + n
+		if alias == real {
+			continue
+		}
+		aliasPath := filepath.Join(toolsetsDir, alias)
+		if exists(aliasPath) {
+			continue
+		}
+		if err := os.Symlink(real, aliasPath); err != nil {
+			return err
+		}
+	}
+	return nil
+}

internal/install/platformtoolsets_test.go

@@ -0,0 +1,106 @@
+package install
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/Cheviiot/vintner/internal/wineenv"
+)
+
+func TestAliasPlatformToolsetsAliasesRealToolset(t *testing.T) {
+	dest := t.TempDir()
+	toolsetsDir := filepath.Join(dest, "MSBuild", "Microsoft", "VC", "v180", "Platforms", "x64", "PlatformToolsets")
+	realDir := filepath.Join(toolsetsDir, "v145")
+	if err := os.MkdirAll(realDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(realDir, "Toolset.props"), []byte("<Project/>"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	// A WDK toolset entry alongside it - must not be mistaken for the real
+	// numeric toolset or itself get aliased over.
+	if err := os.MkdirAll(filepath.Join(toolsetsDir, "WindowsKernelModeDriver10.0"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := aliasPlatformToolsets(dest); err != nil {
+		t.Fatalf("aliasPlatformToolsets: %v", err)
+	}
+
+	for _, n := range wineenv.KnownPlatformToolsets {
+		alias := filepath.Join(toolsetsDir, "v"+n)
+		fi, err := os.Lstat(alias)
+		if err != nil {
+			t.Errorf("expected v%s alias to exist: %v", n, err)
+			continue
+		}
+		if fi.Mode()&os.ModeSymlink == 0 {
+			t.Errorf("v%s should be a symlink, got mode %v", n, fi.Mode())
+			continue
+		}
+		target, err := os.Readlink(alias)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if target != "v145" {
+			t.Errorf("v%s symlink target = %q, want \"v145\"", n, target)
+		}
+		// Follow the alias and confirm it actually reaches the real content.
+		if !isFile(filepath.Join(toolsetsDir, "v"+n, "Toolset.props")) {
+			t.Errorf("v%s/Toolset.props not reachable through the alias", n)
+		}
+	}
+
+	if exists(filepath.Join(toolsetsDir, "WindowsKernelModeDriver10.0", "v"+wineenv.KnownPlatformToolsets[0])) {
+		t.Error("WDK toolset directory should not have been touched")
+	}
+}
+
+func TestAliasPlatformToolsetsDoesNotOverwriteExisting(t *testing.T) {
+	dest := t.TempDir()
+	toolsetsDir := filepath.Join(dest, "MSBuild", "Microsoft", "VC", "v180", "Platforms", "x64", "PlatformToolsets")
+	if err := os.MkdirAll(filepath.Join(toolsetsDir, "v145"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	// v142 already genuinely installed (e.g. a real VS install with several
+	// side-by-side toolsets) - must be left alone, not replaced with an alias.
+	real142 := filepath.Join(toolsetsDir, "v142")
+	if err := os.MkdirAll(real142, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(real142, "Toolset.props"), []byte("<!-- real v142 -->"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := aliasPlatformToolsets(dest); err != nil {
+		t.Fatalf("aliasPlatformToolsets: %v", err)
+	}
+
+	fi, err := os.Lstat(real142)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fi.Mode()&os.ModeSymlink != 0 {
+		t.Error("pre-existing v142 directory should not have been replaced with a symlink")
+	}
+}
+
+func TestAliasPlatformToolsetsNoNumericToolset(t *testing.T) {
+	dest := t.TempDir()
+	// Only a WDK-style toolset present, nothing numeric to alias from.
+	toolsetsDir := filepath.Join(dest, "MSBuild", "Microsoft", "VC", "v180", "Platforms", "x64", "PlatformToolsets")
+	if err := os.MkdirAll(filepath.Join(toolsetsDir, "WindowsUserModeDriver10.0"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := aliasPlatformToolsets(dest); err != nil {
+		t.Fatalf("aliasPlatformToolsets: %v", err)
+	}
+
+	for _, n := range wineenv.KnownPlatformToolsets {
+		if exists(filepath.Join(toolsetsDir, "v"+n)) {
+			t.Errorf("v%s should not have been created with no real numeric toolset present", n)
+		}
+	}
+}

internal/wineenv/platformtoolsets.go

@@ -0,0 +1,15 @@
+package wineenv
+
+// KnownPlatformToolsets are every numeric PlatformToolset short name
+// Microsoft.Cpp.Default.props has ever defined a
+// _PlatformToolsetShortNameFor_v<N> entry for (VS2013 through the VS2022
+// initial release; excludes the _xp/_wp80/_wp81 variants, which aren't
+// purely numeric). vintner only ever installs one compiler generation, but
+// real .vcxproj files in the wild are pinned to whichever generation they
+// were last edited under - v142 (VS2019) for anything not yet retargeted is
+// extremely common. Shared between internal/install (which symlinks these
+// names onto the one real MSBuild PlatformToolsets directory) and
+// internal/wrapper (which mirrors the same names onto VCInstallDir_<N>/
+// VCToolsInstallDir_<N> for the older, environment-variable-driven toolset
+// redirect chain) - see doc comments there for why both are needed.
+var KnownPlatformToolsets = []string{"90", "100", "110", "120", "140", "141", "142", "143"}

internal/wrapper/msbuildenv.go

@@ -29,7 +29,28 @@ func msbuildEnv(cfg *wineenv.Config, paths *wineenv.Paths) map[string]string {
 		// tools onto the same UTC clock removes the mismatch.
 		"TZ": "UTC",
 
+		// VCToolsVersion must be a real version string, not left unset:
+		// Microsoft.Cpp.VCTools.props itself falls back to the literal
+		// placeholder "VCToolsVersion_is_not_defined" whenever it's empty,
+		// and that placeholder then reaches unconditional (not gated behind
+		// CheckMSVCComponents) version-string comparisons elsewhere in
+		// Microsoft.CppBuild.targets, e.g. the SegmentHeap manifest check's
+		// VersionGreaterThanOrEquals(), which throws MSB4184 on a
+		// non-version string.
+		//
+		// CheckMSVCComponents=false is what actually makes an aliased
+		// PlatformToolset safe to combine with that real version: without
+		// it, CheckVCToolsetVersion (Microsoft.CppBuild.targets, MSB8052)
+		// rejects the combination whenever VCToolsVersion's numeric
+		// generation doesn't match PlatformToolset's - exactly the legacy-
+		// project case toolsetSuffixes/aliasPlatformToolsets exist for (a
+		// v142 project against the one real, newer compiler actually
+		// installed). Everything else CheckMSVCComponents gates
+		// (Microsoft.CppBuild.targets ~495-535) is diagnostic-only - MFC/ATL/
+		// Spectre component presence warnings, none of it feeding into the
+		// actual compile/link - so disabling it costs nothing here.
 		"DisableRegistryUse":  "true",
+		"CheckMSVCComponents": "false",
 		"VCToolsVersion":      cfg.MSVCVer,
 		"VsInstallRoot":       paths.BaseWin + `\`,
 		"VSInstallDir":        paths.BaseWin + `\`,
@@ -58,20 +79,29 @@ func msbuildEnv(cfg *wineenv.Config, paths *wineenv.Paths) map[string]string {
 		"Platform": msbuildPlatform(cfg.Arch),
 	}
 
-	// Microsoft.Cpp.props resolves the compiler/toolset location through
+	// VCInstallDir_<N>/VCToolsInstallDir_<N> are consulted under two
-	// VCInstallDir_<N>/VCToolsInstallDir_<N>, where <N> is whatever numeric
+	// completely different numbering schemes, both needing the single real
-	// suffix the installed MSBuild toolset property sheets use (e.g.
+	// toolchain behind every <N> they might ask for:
-	// .../MSBuild/Microsoft/VC/v180 -> "180"). Populate every one actually
+	//
-	// present, so a project pinned to any of them resolves to the one real
+	//  - Microsoft.Cpp.Default.props keys its early "is this toolset even
-	// toolchain that's installed.
+	//    installed" check (the one MSB8020 comes from) off <N> = the
-	matches, _ := filepath.Glob(filepath.Join(paths.BaseUnix, "MSBuild", "Microsoft", "VC", "v*"))
+	//    PlatformToolset suffix a .vcxproj actually declares (v142, v143,
-	for _, m := range matches {
+	//    v145, ...) - the same short name Microsoft stamps on
-		sub := reToolsetDir.FindStringSubmatch(filepath.Base(m))
+	//    VC/Auxiliary/Build/Microsoft.VCToolsVersion.v<N>.default.props for
-		if sub == nil {
+	//    the downloaded compiler.
-			continue
+	//  - Microsoft.CppBuild.targets (MSB8070) instead keys off <N> = the
-		}
+	//    MSBuild targets-schema version whose Microsoft.Cpp.props ended up
-		env["VCInstallDir_"+sub[1]] = paths.MSVCBaseWin + `\`
+	//    imported for this run (MSBuild/Microsoft/VC/v150|v160|v170|v180 -
-		env["VCToolsInstallDir_"+sub[1]] = paths.MSVCDirWin + `\`
+	//    fixed, shipped identically with every MSBuild release, unrelated to
+	//    which compiler is installed), to locate the specific toolset
+	//    version subfolder.
+	//
+	// Populate every <N> from both sources, all pointing at the one real
+	// toolchain that's installed, so a project pinned to any PlatformToolset
+	// resolves at every stage MSBuild checks it.
+	for _, n := range toolsetSuffixes(paths.BaseUnix) {
+		env["VCInstallDir_"+n] = paths.MSVCBaseWin + `\`
+		env["VCToolsInstallDir_"+n] = paths.MSVCDirWin + `\`
 	}
 
 	if strings.HasSuffix(paths.MSBuildBinDir, "amd64") {
@@ -94,6 +124,100 @@ func msbuildEnv(cfg *wineenv.Config, paths *wineenv.Paths) map[string]string {
 	return env
 }
 
+// toolsetSuffixes collects every numeric <N> that either VCInstallDir_<N>
+// lookup mechanism (see msbuildEnv) might be asked to resolve for this
+// installation: PlatformToolset short names from
+// vc/Auxiliary/Build/Microsoft.VCToolsVersion.v<N>.default.props, MSBuild
+// targets-schema versions from MSBuild/Microsoft/VC/v<N>, and every
+// historical PlatformToolset name (see wineenv.KnownPlatformToolsets) - a
+// project pinned to any of them all resolves to the one real toolchain
+// installed.
+func toolsetSuffixes(baseUnix string) []string {
+	seen := map[string]bool{}
+	var suffixes []string
+
+	record := func(n string) {
+		if seen[n] {
+			return
+		}
+		seen[n] = true
+		suffixes = append(suffixes, n)
+	}
+
+	add := func(dir, prefix, suffix string) {
+		matches, _ := filepath.Glob(filepath.Join(dir, "*"))
+		for _, m := range matches {
+			name := filepath.Base(m)
+			if prefix != "" {
+				if !strings.HasPrefix(name, prefix) {
+					continue
+				}
+				name = strings.TrimPrefix(name, prefix)
+			}
+			name = strings.TrimSuffix(name, suffix)
+			sub := reToolsetDir.FindStringSubmatch(name)
+			if sub == nil {
+				continue
+			}
+			record(sub[1])
+		}
+	}
+
+	add(filepath.Join(baseUnix, "vc", "Auxiliary", "Build"), "Microsoft.VCToolsVersion.", ".default.props")
+	add(filepath.Join(baseUnix, "MSBuild", "Microsoft", "VC"), "", "")
+	for _, n := range wineenv.KnownPlatformToolsets {
+		record(n)
+	}
+
+	return suffixes
+}
+
+// reGlobalProp matches an MSBuild global-property command-line switch
+// ("/p:Name=...", "-property:Name=...", case-insensitive on both the
+// -p/-property spelling and the property name) so msbuildGlobalArgs can tell
+// whether the caller already pinned a given property themselves.
+func reGlobalProp(name string) *regexp.Regexp {
+	return regexp.MustCompile(`(?i)^[-/](p|property):` + regexp.QuoteMeta(name) + `=`)
+}
+
+// msbuildGlobalArgs returns /p: switches to prepend to an MSBuild invocation,
+// one per forced property not already present in args.
+//
+// WindowsTargetPlatformVersion is the one property that needs this rather
+// than an env var: unlike VCInstallDir_<N> (an input to a props-file
+// *lookup*, so any value msbuildEnv sets is visible no matter what a project
+// pins its PlatformToolset to), WindowsTargetPlatformVersion is itself the
+// value most legacy .vcxproj files hardcode directly in a PropertyGroup -
+// and an explicit PropertyGroup assignment always wins over an inherited
+// environment variable of the same name. A command-line global property is
+// the one thing a project file can't override, which is exactly what's
+// needed here: vintner only ever installs one Windows SDK version, so - same
+// reasoning as the PlatformToolset fallback above - any project should
+// transparently build against that one installed version rather than fail
+// outright over an exact version string it happened to be pinned to when
+// last saved from a real Windows SDK selector dropdown.
+func msbuildGlobalArgs(cfg *wineenv.Config, args []string) []string {
+	forced := map[string]string{
+		"WindowsTargetPlatformVersion": cfg.SDKVer,
+	}
+
+	var out []string
+	for name, value := range forced {
+		re := reGlobalProp(name)
+		alreadySet := false
+		for _, a := range args {
+			if re.MatchString(a) {
+				alreadySet = true
+				break
+			}
+		}
+		if !alreadySet {
+			out = append(out, "/p:"+name+"="+value)
+		}
+	}
+	return out
+}
+
 func msbuildPlatform(arch string) string {
 	switch arch {
 	case "x86":

internal/wrapper/msbuildenv_test.go

@@ -39,6 +39,14 @@ func TestMsbuildEnvBasics(t *testing.T) {
 	if env["DisableRegistryUse"] != "true" {
 		t.Errorf(`env["DisableRegistryUse"] = %q, want "true"`, env["DisableRegistryUse"])
 	}
+	if env["CheckMSVCComponents"] != "false" {
+		t.Errorf(`env["CheckMSVCComponents"] = %q, want "false" (else CheckVCToolsetVersion errors on an aliased PlatformToolset)`, env["CheckMSVCComponents"])
+	}
+	// VCToolsVersion must be a real version string (see msbuildEnv's doc
+	// comment on it: leaving it unset makes Microsoft.Cpp.VCTools.props
+	// substitute a placeholder that then breaks unconditional version
+	// comparisons elsewhere). CheckMSVCComponents=false is what keeps this
+	// safe to combine with an aliased PlatformToolset.
 	if env["VCToolsVersion"] != cfg.MSVCVer {
 		t.Errorf(`env["VCToolsVersion"] = %q, want %q`, env["VCToolsVersion"], cfg.MSVCVer)
 	}
@@ -61,7 +69,24 @@ func TestMsbuildEnvDiscoversEveryToolsetVersion(t *testing.T) {
 	cfg := &wineenv.Config{Arch: "x64", Host: "x64", DotnetHost: "amd64", MSVCVer: "14.51.36231", SDKVer: "10.0.26100.0"}
 	paths, base := newTestPaths(t, cfg)
 
-	for _, v := range []string{"v145", "v180", "not-a-version"} {
+	// Real layout has two independent sources feeding VCInstallDir_<N>/
+	// VCToolsInstallDir_<N> (see toolsetSuffixes' doc comment for why both
+	// are needed): the PlatformToolset short names a downloaded compiler
+	// ships default-props for, and MSBuild's own fixed schema-version dirs.
+	buildDir := filepath.Join(base, "vc", "Auxiliary", "Build")
+	if err := os.MkdirAll(buildDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	for _, name := range []string{
+		"Microsoft.VCToolsVersion.v145.default.props",
+		"Microsoft.VCToolsVersion.v143.default.props",
+		"Microsoft.VCToolsVersion.default.props", // no version suffix - must not match
+	} {
+		if err := os.WriteFile(filepath.Join(buildDir, name), nil, 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, v := range []string{"v180", "not-a-version"} {
 		if err := os.MkdirAll(filepath.Join(base, "MSBuild", "Microsoft", "VC", v), 0o755); err != nil {
 			t.Fatal(err)
 		}
@@ -69,7 +94,7 @@ func TestMsbuildEnvDiscoversEveryToolsetVersion(t *testing.T) {
 
 	env := msbuildEnv(cfg, paths)
 
-	for _, n := range []string{"145", "180"} {
+	for _, n := range []string{"145", "143", "180"} {
 		if _, ok := env["VCInstallDir_"+n]; !ok {
 			t.Errorf("expected VCInstallDir_%s to be set", n)
 		}
@@ -82,6 +107,64 @@ func TestMsbuildEnvDiscoversEveryToolsetVersion(t *testing.T) {
 	}
 }
 
+func TestToolsetSuffixesDedupsOverlap(t *testing.T) {
+	base := t.TempDir()
+	buildDir := filepath.Join(base, "vc", "Auxiliary", "Build")
+	if err := os.MkdirAll(buildDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(buildDir, "Microsoft.VCToolsVersion.v180.default.props"), nil, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(filepath.Join(base, "MSBuild", "Microsoft", "VC", "v180"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	got := toolsetSuffixes(base)
+	count := 0
+	for _, n := range got {
+		if n == "180" {
+			count++
+		}
+	}
+	if count != 1 {
+		t.Errorf("toolsetSuffixes() returned %q with %d entries for \"180\" (from both sources), want exactly 1", got, count)
+	}
+}
+
+func TestMsbuildGlobalArgsForcesWindowsTargetPlatformVersion(t *testing.T) {
+	cfg := &wineenv.Config{SDKVer: "10.0.26100.0"}
+
+	got := msbuildGlobalArgs(cfg, []string{"Foo.sln", "/p:Configuration=Release"})
+	want := "/p:WindowsTargetPlatformVersion=10.0.26100.0"
+	found := false
+	for _, a := range got {
+		if a == want {
+			found = true
+		}
+	}
+	if !found {
+		t.Errorf("msbuildGlobalArgs(...) = %v, want it to contain %q", got, want)
+	}
+}
+
+func TestMsbuildGlobalArgsRespectsExplicitOverride(t *testing.T) {
+	cfg := &wineenv.Config{SDKVer: "10.0.26100.0"}
+
+	for _, explicit := range []string{
+		"/p:WindowsTargetPlatformVersion=10.0.19041.0",
+		"-p:WindowsTargetPlatformVersion=10.0.19041.0",
+		"/property:WindowsTargetPlatformVersion=10.0.19041.0",
+	} {
+		got := msbuildGlobalArgs(cfg, []string{"Foo.sln", explicit})
+		for _, a := range got {
+			if reGlobalProp("WindowsTargetPlatformVersion").MatchString(a) {
+				t.Errorf("msbuildGlobalArgs with explicit %q also injected %q - should have left the caller's value alone", explicit, a)
+			}
+		}
+	}
+}
+
 func TestMsbuildEnvDetectsWDKContentRoot(t *testing.T) {
 	cfg := &wineenv.Config{Arch: "x64", Host: "x64", DotnetHost: "amd64", MSVCVer: "14.51.36231", SDKVer: "10.0.26100.0"}
 	paths, base := newTestPaths(t, cfg)

internal/wrapper/run.go

@@ -83,8 +83,10 @@ func Run(tool string, args []string) int {
 		// MSBuild: skip all filtering/toolrelay (its output is meant to be
 		// read as-is), and add the extra environment MSBuild's own
 		// toolset/SDK-detection props need on top of the generic
-		// INCLUDE/LIB/WINEPATH.
+		// INCLUDE/LIB/WINEPATH, plus any global properties a project file
-		cmd := exec.Command(wineBin, append([]string{toolExePath}, rewritten...)...)
+		// itself could otherwise override (see msbuildGlobalArgs).
+		msArgs := append(msbuildGlobalArgs(cfg, rewritten), rewritten...)
+		cmd := exec.Command(wineBin, append([]string{toolExePath}, msArgs...)...)
 		env := buildEnv(paths)
 		for k, v := range msbuildEnv(cfg, paths) {
 			env = append(env, k+"="+v)