fix: strip shell comment lines before parsing claude_args (#1055)

shell-quote treats # as a shell comment character, swallowing all
subsequent content including flags on new lines. Strip comment lines
(lines starting with #) before passing input to shell-quote.

Fixes #802

Co-authored-by: VoidChecksum <Admin@CyberNord>

base-action/src/parse-sdk-options.ts

@@ -79,6 +79,20 @@ function mergeMcpConfigs(configValues: string[]): string {
   return JSON.stringify(merged);
 }
 
+/**
+ * Strip comment lines from a shell argument string.
+ * Lines whose first non-whitespace character is `#` are removed entirely.
+ * Inline `#` within a line (e.g. inside a quoted value) is left untouched
+ * because shell-quote handles quoting — we only need to remove full comment lines
+ * before shell-quote sees them.
+ */
+function stripShellComments(input: string): string {
+  return input
+    .split("\n")
+    .filter((line) => !line.trim().startsWith("#"))
+    .join("\n");
+}
+
 /**
  * Parse claudeArgs string into extraArgs record for SDK pass-through
  * The SDK/CLI will handle --mcp-config, --json-schema, etc.
@@ -92,7 +106,7 @@ function parseClaudeArgsToExtraArgs(
   if (!claudeArgs?.trim()) return {};
 
   const result: Record<string, string | null> = {};
-  const args = parseShellArgs(claudeArgs).filter(
+  const args = parseShellArgs(stripShellComments(claudeArgs)).filter(
     (arg): arg is string => typeof arg === "string",
   );
 

base-action/test/parse-sdk-options.test.ts

@@ -313,6 +313,42 @@ describe("parseSdkOptions", () => {
     });
   });
 
+  describe("shell comment stripping", () => {
+    test("should parse flags before and after a comment line", () => {
+      const options: ClaudeOptions = {
+        claudeArgs: "--model 'claude-haiku'\n# comment\n--allowed-tools 'Edit'",
+      };
+
+      const result = parseSdkOptions(options);
+
+      expect(result.sdkOptions.extraArgs?.["model"]).toBe("claude-haiku");
+      expect(result.sdkOptions.allowedTools).toEqual(["Edit"]);
+    });
+
+    test("should parse flags correctly when no comments are present", () => {
+      const options: ClaudeOptions = {
+        claudeArgs: "--model 'claude-haiku'",
+      };
+
+      const result = parseSdkOptions(options);
+
+      expect(result.sdkOptions.extraArgs?.["model"]).toBe("claude-haiku");
+    });
+
+    test("should not strip inline # that appears inside a quoted value", () => {
+      const options: ClaudeOptions = {
+        claudeArgs: "--model 'claude-haiku' --prompt 'use color #ff0000'",
+      };
+
+      const result = parseSdkOptions(options);
+
+      expect(result.sdkOptions.extraArgs?.["model"]).toBe("claude-haiku");
+      expect(result.sdkOptions.extraArgs?.["prompt"]).toBe(
+        "use color #ff0000",
+      );
+    });
+  });
+
   describe("environment variables passthrough", () => {
     test("should include OTEL environment variables in sdkOptions.env", () => {
       // Set up test environment variables