Fix ssh attach script syntax error with compound commands

Packages/macOS/CmuxFoundation/Sources/CmuxFoundation/SSHPTYAttachExitCode.swift

@@ -63,6 +63,10 @@ public enum SSHPTYAttachExitCode: Int32 {
 
     /// Builds the POSIX shell loop shared by persistent SSH PTY attach entry points.
     ///
+    /// The attach environment is exported on its own lines rather than as an
+    /// assignment prefix, because a prefix is only legal before a simple command
+    /// and callers legitimately pass compound commands.
+    ///
     /// - Parameters:
     ///   - command: The shell command that performs one attach attempt.
     ///   - reauthenticates: Whether transient failures should request foreground authentication.
@@ -99,7 +103,11 @@ public enum SSHPTYAttachExitCode: Int32 {
             "  fi",
             "  if [ \"$cmux_ssh_attach_reauth_required\" -eq 0 ]; then",
             "  if [ \"$cmux_ssh_attach_reconnect_unbounded\" -eq 1 ] || [ \"$cmux_ssh_attach_retry\" -lt \"$cmux_ssh_attach_reconnect_limit\" ]; then cmux_ssh_attach_can_retry=1; else cmux_ssh_attach_can_retry=0; fi",
-            "  CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY=\"$cmux_ssh_attach_can_retry\" CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY=\"$cmux_ssh_attach_no_progress_retry\" CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT=\"$cmux_ssh_attach_no_progress_limit\" \(command)",
+            "  CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY=\"$cmux_ssh_attach_can_retry\"",
+            "  CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY=\"$cmux_ssh_attach_no_progress_retry\"",
+            "  CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT=\"$cmux_ssh_attach_no_progress_limit\"",
+            "  export CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT",
+            "  \(command)",
             "  cmux_ssh_attach_status=$?",
             "  case \"$cmux_ssh_attach_status\" in",
             "    \(noProgressPolicy.status)) cmux_ssh_attach_no_progress_retry=$((cmux_ssh_attach_no_progress_retry + 1)); cmux_ssh_attach_reconnect_delay=\"$cmux_ssh_attach_reconnect_initial_delay\"; \(noProgressPolicy.limitReachedCommand) ;;",

Packages/macOS/CmuxFoundation/Sources/CmuxFoundation/SSHPTYAttachRetryScriptBuilder.swift

@@ -15,6 +15,10 @@ public struct SSHPTYAttachRetryScriptBuilder: Sendable {
     /// `reauthenticates` is true and installs `cmux_ssh_attach_signal_exit`
     /// before these lines execute.
     ///
+    /// The attach environment is exported on its own lines rather than as an
+    /// assignment prefix, because a prefix is only legal before a simple command
+    /// and callers legitimately pass compound commands.
+    ///
     /// - Parameters:
     ///   - command: Shell command that performs one PTY attachment attempt.
     ///   - reauthenticates: Whether status 255 requires foreground authentication before reattaching.
@@ -67,7 +71,11 @@ public struct SSHPTYAttachRetryScriptBuilder: Sendable {
             "  fi",
             "  if [ \"$cmux_ssh_attach_reauth_required\" -eq 0 ]; then",
             "  if [ \"$cmux_ssh_attach_reconnect_unbounded\" -eq 1 ] || [ \"$cmux_ssh_attach_retry\" -lt \"$cmux_ssh_attach_reconnect_limit\" ]; then cmux_ssh_attach_can_retry=1; else cmux_ssh_attach_can_retry=0; fi",
-            "  CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY=\"$cmux_ssh_attach_can_retry\" CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY=\"$cmux_ssh_attach_no_progress_retry\" CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT=\"$cmux_ssh_attach_no_progress_limit\" \(command)",
+            "  CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY=\"$cmux_ssh_attach_can_retry\"",
+            "  CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY=\"$cmux_ssh_attach_no_progress_retry\"",
+            "  CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT=\"$cmux_ssh_attach_no_progress_limit\"",
+            "  export CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT",
+            "  \(command)",
             "  cmux_ssh_attach_status=$?",
             "  case \"$cmux_ssh_attach_status\" in",
             "    \(noProgressStatus)) cmux_ssh_attach_no_progress_retry=$((cmux_ssh_attach_no_progress_retry + 1)); cmux_ssh_attach_reconnect_delay=\"$cmux_ssh_attach_reconnect_initial_delay\"; \(noProgressPolicy.limitReachedCommand) ;;",

Packages/macOS/CmuxFoundation/Tests/CmuxFoundationTests/SSHPTYAttachExitCodeTests.swift

@@ -65,6 +65,38 @@ struct SSHPTYAttachExitCodeTests {
         #expect(!fileManager.fileExists(atPath: authAttempts.path))
     }
 
+    // Regression for #9443: env-assignment prefixes are only legal before a
+    // simple command, so a compound attach command used to produce
+    // "syntax error near unexpected token `then'".
+    @Test("retry loop stays valid POSIX shell for compound attach commands")
+    func retryLoopAcceptsCompoundAttachCommands() throws {
+        let compoundCommand = [
+            "if [ \"$cmux_ssh_attach_no_progress_retry\" -gt 0 ]; then :; fi",
+            "exit 0",
+        ].joined(separator: "\n")
+        let script = SSHPTYAttachExitCode.retryLoopLines(
+            command: compoundCommand,
+            reauthenticates: false
+        ).joined(separator: "\n")
+        let scriptURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-pty-retry-syntax-\(UUID().uuidString).sh")
+        defer { try? FileManager.default.removeItem(at: scriptURL) }
+        try (script + "\n").write(to: scriptURL, atomically: true, encoding: .utf8)
+
+        let process = Process()
+        let stderrPipe = Pipe()
+        process.executableURL = URL(fileURLWithPath: "/bin/sh")
+        process.arguments = ["-n", scriptURL.path]
+        process.standardError = stderrPipe
+        try process.run()
+        process.waitUntilExit()
+        let stderr = String(
+            data: stderrPipe.fileHandleForReading.readDataToEndOfFile(),
+            encoding: .utf8
+        ) ?? ""
+        #expect(process.terminationStatus == 0, "\(stderr)\n\(script)")
+    }
+
     @Test("lifecycle codes retain precedence over transient-looking messages")
     func lifecycleCodesRetainPrecedence() {
         #expect(

Packages/macOS/CmuxFoundation/Tests/CmuxFoundationTests/SSHPTYAttachRetryScriptBuilderTests.swift

@@ -74,6 +74,47 @@ struct SSHPTYAttachRetryScriptBuilderTests {
         #expect(try String(contentsOf: logURL, encoding: .utf8) == "attach\nsleep:2\nattach\n")
     }
 
+    // Regression for #9443: the loop used to prefix the attach command with env
+    // assignments, which POSIX only allows before a simple command, so a compound
+    // attach command made the generated cmux-ssh-startup script fail with
+    // "syntax error near unexpected token `then'".
+    @Test func retryLoopIsValidPOSIXShellForCompoundAttachCommands() throws {
+        let logURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-ssh-attach-compound-\(UUID().uuidString)")
+        let scriptURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("cmux-ssh-attach-compound-\(UUID().uuidString).sh")
+        defer {
+            try? FileManager.default.removeItem(at: logURL)
+            try? FileManager.default.removeItem(at: scriptURL)
+        }
+
+        let compoundCommand = [
+            "if [ \"$cmux_ssh_attach_no_progress_retry\" -gt 0 ]; then : || exit 1; fi",
+            "printf '%s/%s/%s\\n' \"$CMUX_SSH_PTY_ATTACH_WRAPPER_CAN_RETRY\" \"$CMUX_SSH_PTY_ATTACH_NO_PROGRESS_RETRY\" \"$CMUX_SSH_PTY_ATTACH_NO_PROGRESS_LIMIT\" >> \"$CMUX_TEST_LOG\"",
+            "exit 0",
+        ].joined(separator: "\n")
+        let script = SSHPTYAttachRetryScriptBuilder().lines(
+            command: compoundCommand,
+            reauthenticates: false
+        ).joined(separator: "\n")
+        try (script + "\n").write(to: scriptURL, atomically: true, encoding: .utf8)
+
+        let syntaxCheck = try run("/bin/sh -n '\(scriptURL.path)'", environment: [:])
+        #expect(syntaxCheck.status == 0, "\(syntaxCheck.stderr)\n\(script)")
+
+        // The loop must still hand the retry budget to the command it runs.
+        let execution = try run(
+            script,
+            environment: [
+                "CMUX_TEST_LOG": logURL.path,
+                "CMUX_SSH_RECONNECT_LIMIT": "",
+                "CMUX_SSH_PTY_NO_PROGRESS_RETRY_LIMIT": "3",
+            ]
+        )
+        #expect(execution.status == 0, "\(execution.stderr)")
+        #expect(try String(contentsOf: logURL, encoding: .utf8) == "1/0/3\n")
+    }
+
     @Test func unclassifiedReauthenticationFailsClosedAfterEstablishedSession() throws {
         let logURL = FileManager.default.temporaryDirectory
             .appendingPathComponent("cmux-ssh-attach-unclassified-reauth-\(UUID().uuidString)")