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Add InheritEnvironmentVariables to StdioClientTransportOptions (#1563)

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This commit is contained in:
Stephen Halter 2026-05-08 10:38:48 -07:00 • committed by Jeff Handley
commit d34fac48d5
1 changed files with 395 additions and 6 deletions
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182
tests/ModelContextProtocol.Tests/Transport/StdioClientTransportTests.cs
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@ -150,6 +150,188 @@ public class StdioClientTransportTests(ITestOutputHelper testOutputHelper) : Log
Assert.Equal(cliArgumentValue ?? "", content.Text);
}
[Fact(Skip = "Platform not supported by this test.", SkipUnless = nameof(IsStdErrCallbackSupported))]
public async Task InheritEnvironmentVariables_DefaultTrue_ChildSeesParentEnvVars()
{
// Check the same variable the False test checks for absence (HOME on Unix, USERNAME on Windows)
// so the two tests form a direct symmetric pair: one asserts it IS set, the other asserts it is NOT.
var tcs = new TaskCompletionSource<string>();
StdioClientTransport transport = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ?
new(new() { Command = "cmd", Arguments = ["/c", "if defined USERNAME (echo USERNAME_IS_SET >&2) else (echo USERNAME_NOT_SET >&2) & exit /b 1"], StandardErrorLines = line => tcs.TrySetResult(line) }, LoggerFactory) :
new(new() { Command = "sh", Arguments = ["-c", "if [ -n \"$HOME\" ]; then echo HOME_IS_SET >&2; else echo HOME_NOT_SET >&2; fi; exit 1"], StandardErrorLines = line => tcs.TrySetResult(line) }, LoggerFactory);
await Assert.ThrowsAnyAsync<IOException>(() => McpClient.CreateAsync(transport, loggerFactory: LoggerFactory, cancellationToken: TestContext.Current.CancellationToken));
using var cts = new CancellationTokenSource(TestConstants.DefaultTimeout);
string capturedLine = await tcs.Task.WaitAsync(cts.Token);
Assert.Equal(RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "USERNAME_IS_SET" : "HOME_IS_SET", capturedLine.Trim());
}
[Fact(Skip = "Platform not supported by this test.", SkipUnless = nameof(IsStdErrCallbackSupported))]
public async Task InheritEnvironmentVariables_False_ChildDoesNotSeeParentEnvVars()
{
// Pass PATH so cmd/sh can be located. Verify that HOME (Unix) / USERNAME (Windows),
// which are always set in the parent, are absent because they were not explicitly provided.
var tcs = new TaskCompletionSource<string>();
StdioClientTransport transport = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ?
new(new()
{
Command = "cmd",
Arguments = ["/c", "if defined USERNAME (echo USERNAME_IS_SET >&2) else (echo USERNAME_NOT_SET >&2) & exit /b 1"],
InheritEnvironmentVariables = false,
EnvironmentVariables = new Dictionary<string, string?> { ["PATH"] = Environment.GetEnvironmentVariable("PATH") },
StandardErrorLines = line => tcs.TrySetResult(line)
}, LoggerFactory) :
new(new()
{
Command = "sh",
Arguments = ["-c", "if [ -n \"$HOME\" ]; then echo HOME_IS_SET >&2; else echo HOME_NOT_SET >&2; fi; exit 1"],
InheritEnvironmentVariables = false,
EnvironmentVariables = new Dictionary<string, string?> { ["PATH"] = Environment.GetEnvironmentVariable("PATH") },
StandardErrorLines = line => tcs.TrySetResult(line)
}, LoggerFactory);
await Assert.ThrowsAnyAsync<IOException>(() => McpClient.CreateAsync(transport, loggerFactory: LoggerFactory, cancellationToken: TestContext.Current.CancellationToken));
using var cts = new CancellationTokenSource(TestConstants.DefaultTimeout);
string capturedLine = await tcs.Task.WaitAsync(cts.Token);
// HOME / USERNAME were in the parent but not passed — should be absent in the child.
Assert.Equal(RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "USERNAME_NOT_SET" : "HOME_NOT_SET", capturedLine.Trim());
}
[Fact(Skip = "Platform not supported by this test.", SkipUnless = nameof(IsStdErrCallbackSupported))]
public async Task InheritEnvironmentVariables_False_WithExplicitVars_ChildSeesOnlyExplicitVars()
{
// Pass PATH + one explicit var. Verify HOME (Unix) / USERNAME (Windows) is absent,
// and the explicitly provided variable is visible.
const string explicitVarName = "MCP_STDIO_TEST_EXPLICIT_VAR";
const string explicitVarValue = "explicit_test_value";
var capturedLines = new List<string>();
var lineCount = 0;
var tcs = new TaskCompletionSource<bool>();
void CaptureLines(string line)
{
lock (capturedLines)
{
capturedLines.Add(line.Trim());
if (Interlocked.Increment(ref lineCount) >= 2)
tcs.TrySetResult(true);
}
}
StdioClientTransport transport = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ?
new(new()
{
Command = "cmd",
Arguments = ["/c",
$"if defined USERNAME (echo USERNAME_IS_SET >&2) else (echo USERNAME_NOT_SET >&2) " +
$"& if defined {explicitVarName} (echo EXPLICIT_IS_SET >&2) else (echo EXPLICIT_NOT_SET >&2) " +
$"& exit /b 1"],
InheritEnvironmentVariables = false,
EnvironmentVariables = new Dictionary<string, string?> { ["PATH"] = Environment.GetEnvironmentVariable("PATH"), [explicitVarName] = explicitVarValue },
StandardErrorLines = CaptureLines
}, LoggerFactory) :
new(new()
{
Command = "sh",
Arguments = ["-c",
$"if [ -n \"$HOME\" ]; then echo HOME_IS_SET >&2; else echo HOME_NOT_SET >&2; fi; " +
$"if [ -n \"${explicitVarName}\" ]; then echo EXPLICIT_IS_SET >&2; else echo EXPLICIT_NOT_SET >&2; fi; exit 1"],
InheritEnvironmentVariables = false,
EnvironmentVariables = new Dictionary<string, string?> { ["PATH"] = Environment.GetEnvironmentVariable("PATH"), [explicitVarName] = explicitVarValue },
StandardErrorLines = CaptureLines
}, LoggerFactory);
await Assert.ThrowsAnyAsync<IOException>(() => McpClient.CreateAsync(transport, loggerFactory: LoggerFactory, cancellationToken: TestContext.Current.CancellationToken));
using var cts = new CancellationTokenSource(TestConstants.DefaultTimeout);
await tcs.Task.WaitAsync(cts.Token);
string allOutput = string.Join(Environment.NewLine, capturedLines);
Assert.Contains(RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "USERNAME_NOT_SET" : "HOME_NOT_SET", allOutput);
Assert.Contains("EXPLICIT_IS_SET", allOutput);
}
[Fact]
public void GetDefaultEnvironmentVariables_ReturnsFreshDictionaryEachCall()
{
var first = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
var second = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
Assert.NotSame(first, second);
}
[Fact]
public void GetDefaultEnvironmentVariables_ReturnsCorrectComparer()
{
var result = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
Assert.Equal(StringComparer.OrdinalIgnoreCase, result.Comparer);
}
else
{
Assert.Equal(StringComparer.Ordinal, result.Comparer);
}
}
[Fact]
public void GetDefaultEnvironmentVariables_ContainsOnlyAllowlistedKeys()
{
HashSet<string> allowedKeys = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
? new(StringComparer.OrdinalIgnoreCase)
{
"APPDATA", "HOMEDRIVE", "HOMEPATH", "LOCALAPPDATA", "PATH", "PATHEXT",
"PROCESSOR_ARCHITECTURE", "PROGRAMFILES", "SYSTEMDRIVE", "SYSTEMROOT",
"TEMP", "USERNAME", "USERPROFILE",
}
: new(StringComparer.Ordinal)
{
"HOME", "LOGNAME", "PATH", "SHELL", "TERM", "USER",
};
var result = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
foreach (var key in result.Keys)
{
Assert.Contains(key, allowedKeys);
}
}
[Fact]
public void GetDefaultEnvironmentVariables_ExcludesShellFunctionValues()
{
// Verify the postcondition: no returned values start with "()" (shell function markers).
var result = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
foreach (var kvp in result)
{
Assert.False(kvp.Value?.StartsWith("()") ?? false,
$"Value for '{kvp.Key}' starts with '()' and should have been filtered as a shell function.");
}
}
[Fact]
public void GetDefaultEnvironmentVariables_PathIsPresent_WhenSetInEnvironment()
{
// PATH is always set in a real process environment; verify it is included.
var result = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
if (Environment.GetEnvironmentVariable("PATH") is not null)
{
Assert.True(result.ContainsKey("PATH"), "PATH should be present when it exists in the parent environment.");
}
}
[Fact]
public void GetDefaultEnvironmentVariables_DoesNotIncludeNonAllowlistedKeys()
{
// Keys that are definitely not on the allowlist must never appear.
var result = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
Assert.False(result.ContainsKey("AWS_SECRET_ACCESS_KEY"));
Assert.False(result.ContainsKey("GITHUB_TOKEN"));
Assert.False(result.ContainsKey("OPENAI_API_KEY"));
}
[Fact]
public async Task SendMessageAsync_Should_Use_LF_Not_CRLF()
{