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fix: fall back to cmd.exe when PowerShell is unavailable on Windows #12034

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fix: fall back to cmd.exe when PowerShell is unavailable on Windows #12034

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38334b1
fix: downgrade console.error to console.debug in DocumentHistoryTrack…
octo-patch Apr 3, 2026
26c16ad
fix: fall back to cmd.exe when PowerShell unavailable on Windows (fix…
octo-patch Apr 4, 2026
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2 changes: 1 addition & 1 deletion core/nextEdit/DocumentHistoryTracker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,7 @@ export class DocumentHistoryTracker {
const documentHistory = this.documentContentHistoryMap.get(documentPath);

if (!astHistory || !documentHistory) {
console.error(`Document ${documentPath} not found in AST tracker`);
console.debug(`Document ${documentPath} not found in AST tracker, adding it`);
this.addDocument(documentPath, documentContent, ast);
return; // Early return - document was added with initial state
}
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54 changes: 47 additions & 7 deletions core/tools/implementations/runTerminalCommand.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -21,13 +21,27 @@ function getDecodedOutput(data: Buffer): string {
} else {
return data.toString();
}
} // Simple helper function to use login shell on Unix/macOS and PowerShell on Windows
}

// Tracks whether PowerShell failed to spawn on Windows (e.g., blocked by corporate policy)
// so subsequent calls can fall back to cmd.exe without retrying PowerShell.
let _powershellUnavailable = false;

// Simple helper function to use login shell on Unix/macOS and PowerShell on Windows
function getShellCommand(command: string): { shell: string; args: string[] } {
if (process.platform === "win32") {
// Windows: Use PowerShell
if (!_powershellUnavailable) {
// Windows: prefer PowerShell for richer command support
return {
shell: "powershell.exe",
args: ["-NoLogo", "-ExecutionPolicy", "Bypass", "-Command", command],
};
}
// PowerShell unavailable (e.g., blocked by corporate security policy);
// fall back to cmd.exe via COMSPEC.
return {
shell: "powershell.exe",
args: ["-NoLogo", "-ExecutionPolicy", "Bypass", "-Command", command],
shell: process.env.COMSPEC || "cmd.exe",
args: ["/D", "/S", "/C", command],
};
} else {
// Unix/macOS: Use login shell to source .bashrc/.zshrc etc.
Expand Down Expand Up @@ -339,7 +353,7 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
}
});

childProc.on("error", (error) => {
childProc.on("error", (error: NodeJS.ErrnoException) => {
// Clear timeout on error
if (timeoutId) {
clearTimeout(timeoutId);
Expand All @@ -360,6 +374,15 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
removeRunningProcess(toolCallId);
}

// If PowerShell failed to spawn on Windows (e.g., blocked by corporate policy),
// mark it unavailable so future calls fall back to cmd.exe automatically.
if (
process.platform === "win32" &&
(error.code === "UNKNOWN" || error.code === "ENOENT")
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@cubic-dev-ai cubic-dev-ai bot Apr 4, 2026 •
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P2: Sticky PowerShell fallback is triggered by broad error codes (UNKNOWN/ENOENT) instead of a PowerShell-specific spawn failure, so one misclassified error can permanently switch future Windows commands to cmd.exe.

Prompt for AI agents 
Check if this issue is valid — if so, understand the root cause and fix it. At core/tools/implementations/runTerminalCommand.ts, line 381:

<comment>Sticky PowerShell fallback is triggered by broad error codes (`UNKNOWN`/`ENOENT`) instead of a PowerShell-specific spawn failure, so one misclassified error can permanently switch future Windows commands to `cmd.exe`.</comment>

<file context>
@@ -360,6 +374,15 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
+            // mark it unavailable so future calls fall back to cmd.exe automatically.
+            if (
+              process.platform === "win32" &&
+              (error.code === "UNKNOWN" || error.code === "ENOENT")
+            ) {
+              _powershellUnavailable = true;
</file context>
Fix with Cubic

) {
_powershellUnavailable = true;
}

reject(error);
});
});
Expand Down Expand Up @@ -458,7 +481,7 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
}
});

childProc.on("error", (error) => {
childProc.on("error", (error: NodeJS.ErrnoException) => {
// Clear timeout on error
if (timeoutId) {
clearTimeout(timeoutId);
Expand All @@ -473,6 +496,16 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
if (toolCallId) {
removeRunningProcess(toolCallId);
}

// If PowerShell failed to spawn on Windows (e.g., blocked by corporate policy),
// mark it unavailable so future calls fall back to cmd.exe automatically.
if (
process.platform === "win32" &&
(error.code === "UNKNOWN" || error.code === "ENOENT")
) {
_powershellUnavailable = true;
}

reject(error);
});
},
Expand Down Expand Up @@ -521,10 +554,17 @@ export const runTerminalCommandImpl: ToolImpl = async (args, extras) => {
}
});

childProc.on("error", () => {
childProc.on("error", (error: NodeJS.ErrnoException) => {
if (isProcessBackgrounded(toolCallId)) {
removeBackgroundedProcess(toolCallId);
}
// If PowerShell failed to spawn on Windows, mark it unavailable for future calls.
if (
process.platform === "win32" &&
(error.code === "UNKNOWN" || error.code === "ENOENT")
) {
_powershellUnavailable = true;
}
});

// Unref the child to allow the Node.js process to exit
Expand Down
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