From 95f7854671d6d884e2c9bd83808b26c30389ee60 Mon Sep 17 00:00:00 2001
From: Larry Ewing <lewing@gmail.com>
Date: Sat, 18 Jul 2026 20:35:01 -0500
Subject: [PATCH 1/3] [wasm] Fix native build failing when temp path contains
 parentheses

RunShellCommand writes the compile command to a temporary batch file under
Path.GetTempPath() and runs it with 'cmd /c "<script>"'. When the temp path
contains characters cmd.exe treats specially - most commonly parentheses from a
Windows user profile name like C:\Users\John(US) - cmd's /c quote handling
strips the surrounding quotes (it sees special characters between the two
quotes) and then mis-parses the now-unquoted path at the first '(', producing:

    'C:\Users\John' is not recognized as an internal or external command

and the whole native (emcc) build fails.

Invoke the script as 'cmd /S /c ""<script>""' instead: /S makes cmd strip
only the outermost pair of quotes and treat the rest verbatim, so the inner
quotes around the path are preserved.

Adds a Windows-only Wasm.Build.Tests regression that runs a native build with
%TMP%/%TEMP% pointed at a directory containing parentheses.

Fixes #120327

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 62dcd5b3-7227-426b-a072-8812e9c4382d
---
 .../wasm/Wasm.Build.Tests/NativeBuildTests.cs | 34 +++++++++++++++++++
 src/tasks/Common/Utils.cs                     |  8 ++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
index 3e107ad21bb180..5b9e460df5f0f4 100644
--- a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
+++ b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
@@ -41,6 +41,40 @@ public async Task SimpleNativeBuild(Configuration config, bool aot)
             await RunForPublishWithWebServer(new BrowserRunOptions(config, ExpectedExitCode: 42));
         }
 
+        [Theory]
+        [BuildAndRun(aot: false)]
+        [TestCategory("native-mono")]
+        [SkipOnPlatform(TestPlatforms.AnyUnix, "The cmd.exe quoting behavior this covers is Windows-specific.")]
+        public async Task NativeBuildWithParenthesesInTempPath(Configuration config, bool aot)
+        {
+            // Regression test for https://github.com/dotnet/runtime/issues/120327.
+            // Native compilation runs the compiler through a temporary batch file created under the
+            // temp directory. Windows user profile names can contain parentheses (e.g. "John(US)"),
+            // which puts parentheses in %TEMP%. `cmd /c "<path>"` then stripped the quotes around
+            // that path and mis-parsed it at the first '(', failing the native build with
+            // "'C:\Users\John' is not recognized as an internal or external command".
+            ProjectInfo info = CreateWasmTemplateProject(
+                Template.WasmBrowser,
+                config,
+                aot,
+                "parens_temp",
+                extraProperties: "<WasmBuildNative>true</WasmBuildNative>");
+
+            UpdateBrowserProgramFile();
+            ReplaceMainJsWithMinimalRunMain();
+
+            string tempWithParens = Path.Combine(BuildEnvironment.TmpPath, $"tmp ({info.ProjectName})");
+            Directory.CreateDirectory(tempWithParens);
+            var envVars = new Dictionary<string, string>
+            {
+                ["TMP"] = tempWithParens,
+                ["TEMP"] = tempWithParens,
+            };
+
+            PublishProject(info, config, new PublishOptions(ExtraBuildEnvironmentVariables: envVars), isNativeBuild: true);
+            await RunForPublishWithWebServer(new BrowserRunOptions(config, ExpectedExitCode: 42));
+        }
+
         [Theory]
         [BuildAndRun(aot: true)]
         [TestCategory("native-mono")]
diff --git a/src/tasks/Common/Utils.cs b/src/tasks/Common/Utils.cs
index 97be25c8559d38..edbaa0fbc3c792 100644
--- a/src/tasks/Common/Utils.cs
+++ b/src/tasks/Common/Utils.cs
@@ -59,8 +59,14 @@ public static (int exitCode, string output) RunShellCommand(
                                         string? label=null)
     {
         string scriptFileName = CreateTemporaryBatchFile(command);
+        // The script path lives under the temp directory, which is typically inside the user
+        // profile (e.g. C:\Users\John(US)\AppData\Local\Temp\...). If that path contains cmd
+        // special characters such as '(' or ')', `cmd /c "<path>"` strips the surrounding quotes
+        // (because it sees special chars between the two quotes) and then mis-parses the now
+        // unquoted path at the first parenthesis. Use `/S` together with an extra pair of quotes
+        // so cmd strips only the outermost quotes and runs the still-quoted path verbatim.
         (string shell, string args) = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
-                                                    ? ("cmd", $"/c \"{scriptFileName}\"")
+                                                    ? ("cmd", $"/S /c \"\"{scriptFileName}\"\"")
                                                     : ("/bin/sh", $"\"{scriptFileName}\"");
 
         string msgPrefix = label == null ? string.Empty : $"[{label}] ";

From 9475ae540b751a28341840d434f8de972c94767c Mon Sep 17 00:00:00 2001
From: Larry Ewing <lewing@gmail.com>
Date: Sat, 18 Jul 2026 20:43:55 -0500
Subject: [PATCH 2/3] Address review: use a random subdirectory for the
 parenthesized temp path

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 62dcd5b3-7227-426b-a072-8812e9c4382d
---
 src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
index 5b9e460df5f0f4..dbabfbd75a5fcb 100644
--- a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
+++ b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
@@ -63,7 +63,7 @@ public async Task NativeBuildWithParenthesesInTempPath(Configuration config, boo
             UpdateBrowserProgramFile();
             ReplaceMainJsWithMinimalRunMain();
 
-            string tempWithParens = Path.Combine(BuildEnvironment.TmpPath, $"tmp ({info.ProjectName})");
+            string tempWithParens = Path.Combine(BuildEnvironment.TmpPath, $"tmp ({GetRandomId()})");
             Directory.CreateDirectory(tempWithParens);
             var envVars = new Dictionary<string, string>
             {

From de9fe31e37703ee278703efc52e5c889a7cb2337 Mon Sep 17 00:00:00 2001
From: Larry Ewing <lewing@gmail.com>
Date: Sat, 18 Jul 2026 20:50:58 -0500
Subject: [PATCH 3/3] Keep unicode (GB18030-style) chars in the temp path
 alongside parentheses

Restore the non-ASCII characters (dropped in the previous commit) so the temp
path exercises both the cmd.exe quoting fix (parentheses) and the UTF-8
(chcp 65001) handling in RunShellCommand, while GetRandomId keeps it unique.
Rename the test accordingly.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 62dcd5b3-7227-426b-a072-8812e9c4382d
---
 src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
index dbabfbd75a5fcb..d02dee1678c1c0 100644
--- a/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
+++ b/src/mono/wasm/Wasm.Build.Tests/NativeBuildTests.cs
@@ -45,7 +45,7 @@ public async Task SimpleNativeBuild(Configuration config, bool aot)
         [BuildAndRun(aot: false)]
         [TestCategory("native-mono")]
         [SkipOnPlatform(TestPlatforms.AnyUnix, "The cmd.exe quoting behavior this covers is Windows-specific.")]
-        public async Task NativeBuildWithParenthesesInTempPath(Configuration config, bool aot)
+        public async Task NativeBuildWithSpecialCharsInTempPath(Configuration config, bool aot)
         {
             // Regression test for https://github.com/dotnet/runtime/issues/120327.
             // Native compilation runs the compiler through a temporary batch file created under the
@@ -53,6 +53,8 @@ public async Task NativeBuildWithParenthesesInTempPath(Configuration config, boo
             // which puts parentheses in %TEMP%. `cmd /c "<path>"` then stripped the quotes around
             // that path and mis-parsed it at the first '(', failing the native build with
             // "'C:\Users\John' is not recognized as an internal or external command".
+            // The unicode chars additionally cover the UTF-8 (chcp 65001) handling in the same
+            // RunShellCommand path, which exists so non-ASCII (e.g. GB18030) temp/user paths work.
             ProjectInfo info = CreateWasmTemplateProject(
                 Template.WasmBrowser,
                 config,
@@ -63,7 +65,7 @@ public async Task NativeBuildWithParenthesesInTempPath(Configuration config, boo
             UpdateBrowserProgramFile();
             ReplaceMainJsWithMinimalRunMain();
 
-            string tempWithParens = Path.Combine(BuildEnvironment.TmpPath, $"tmp ({GetRandomId()})");
+            string tempWithParens = Path.Combine(BuildEnvironment.TmpPath, $"tmp ({GetRandomId()}) {s_unicodeChars}");
             Directory.CreateDirectory(tempWithParens);
             var envVars = new Dictionary<string, string>
             {