refactor(run): marker for heredoc

Commit `a25e2fe`

Eric Bower · 2026-05-20 22:21:35 -0400 EDT

parent d5c6926

refactor(run): marker for heredoc

For most commands we can append `; $?` except for heredoc where the marker
needs to be on its own line.

1 files changed, +28, -14

M src/main.zig

+28, -14

......@@ -1140,17 +1140,33 @@ const Daemon = struct {

        const cmd = payload;

        // Daemon appends the task marker so we know when a task is done with
        // exit status
        const marker = "echo ZMX_TASK_COMPLETED:$?\r";

        // Redirect stdin from /dev/null to prevent interactive programs
        // (pagers, editors, prompts) from blocking the task. Programs that
        // detect a TTY and open a pager (e.g. git, man) or read stdin
        // (e.g. cat, head) will receive EOF instead of blocking. This
        // matches the behavior of CI runners and `tmux send-keys`.
        //
        // Commands that legitimately need stdin should use `zmx send`
        // instead, or pipe data directly: `echo data | zmx run dev cat`.
        // Here-documents still work because the shell processes the
        // here-document before applying the /dev/null redirection.
        const stdin_redirect = "< /dev/null ";

        // Chain the exit marker with `;` on the same line. `$?` captures the
        // exit code of the command (not the `;`). The sole exception is when
        // the command contains a heredoc (`<<`) — the delimiter must be alone
        // on its line, so the marker goes on the next line instead.
        const single_line_marker = "; echo ZMX_TASK_COMPLETED:$?\r";
        const heredoc_marker = "\r\necho ZMX_TASK_COMPLETED:$?\r";
        const uses_heredoc = std.mem.indexOf(u8, cmd, "<<") != null;

        self.queuePtyInput(stdin_redirect);
        if (cmd.len > 0 and cmd[cmd.len - 1] == '\r') {
            self.queuePtyInput(cmd[0 .. cmd.len - 1]);
        } else {
            self.queuePtyInput(cmd);
        }
        self.queuePtyInput("\r");
        self.queuePtyInput(marker);
        self.queuePtyInput(if (uses_heredoc) heredoc_marker else single_line_marker);

        try ipc.appendMessage(self.alloc, &client.write_buf, .Ack, "");
        client.has_pending_output = true;

......@@ -1282,13 +1298,10 @@ fn help() !void {
        \\  Commands run inside a PTY using bash
        \\  Commands are passed as-is: do not wrap in quotes.
        \\  Commands run sequentially: do not send multiple in parallel.
        \\  Avoid interactive programs (pagers, editors, prompts): they hang.
        \\
        \\  If the command hangs, send Ctrl+C to recover:
        \\    zmx run <session> $(printf '\x03')
        \\
        \\  If the command hangs, print the history to see the error:
        \\    zmx history <session> | tail -100
        \\  Stdin is redirected from /dev/null to prevent interactive programs
        \\  (pagers, editors, prompts) from blocking. Use `zmx send` for
        \\  commands that need user input, or pipe data directly:
        \\    echo "data" | zmx run dev cat
        \\
        \\  `-d` will detach from the calling terminal. Use `wait` to track
        \\  its status.

......@@ -1297,7 +1310,8 @@ fn help() !void {
        \\    zmx run dev ls
        \\    zmx run dev zig build
        \\    zmx run dev grep -r TODO src
        \\    zmx run dev git -c core.pager=cat diff
        \\    zmx run dev git log --oneline          # pager won't block
        \\    echo "hello" | zmx run dev cat         # piped stdin still works
        \\
        \\    zmx run dev -d sleep 10
        \\    zmx wait dev

...	...		@@ -1140,17 +1140,33 @@ const Daemon = struct {
1140	1140
1141	1141		const cmd = payload;
1142	1142
1143		-	// Daemon appends the task marker so we know when a task is done with
1144		-	// exit status
1145		-	const marker = "echo ZMX_TASK_COMPLETED:$?\r";
1146		-
	1143	+	// Redirect stdin from /dev/null to prevent interactive programs
	1144	+	// (pagers, editors, prompts) from blocking the task. Programs that
	1145	+	// detect a TTY and open a pager (e.g. git, man) or read stdin
	1146	+	// (e.g. cat, head) will receive EOF instead of blocking. This
	1147	+	// matches the behavior of CI runners and `tmux send-keys`.
	1148	+	//
	1149	+	// Commands that legitimately need stdin should use `zmx send`
	1150	+	// instead, or pipe data directly: `echo data \| zmx run dev cat`.
	1151	+	// Here-documents still work because the shell processes the
	1152	+	// here-document before applying the /dev/null redirection.
	1153	+	const stdin_redirect = "< /dev/null ";
	1154	+
	1155	+	// Chain the exit marker with `;` on the same line. `$?` captures the
	1156	+	// exit code of the command (not the `;`). The sole exception is when
	1157	+	// the command contains a heredoc (`<<`) — the delimiter must be alone
	1158	+	// on its line, so the marker goes on the next line instead.
	1159	+	const single_line_marker = "; echo ZMX_TASK_COMPLETED:$?\r";
	1160	+	const heredoc_marker = "\r\necho ZMX_TASK_COMPLETED:$?\r";
	1161	+	const uses_heredoc = std.mem.indexOf(u8, cmd, "<<") != null;
	1162	+
	1163	+	self.queuePtyInput(stdin_redirect);
1147	1164		if (cmd.len > 0 and cmd[cmd.len - 1] == '\r') {
1148	1165		self.queuePtyInput(cmd[0 .. cmd.len - 1]);
1149	1166		} else {
1150	1167		self.queuePtyInput(cmd);
1151	1168		}
1152		-	self.queuePtyInput("\r");
1153		-	self.queuePtyInput(marker);
	1169	+	self.queuePtyInput(if (uses_heredoc) heredoc_marker else single_line_marker);
1154	1170
1155	1171		try ipc.appendMessage(self.alloc, &client.write_buf, .Ack, "");
1156	1172		client.has_pending_output = true;

...	...		@@ -1282,13 +1298,10 @@ fn help() !void {
1282	1298		\\ Commands run inside a PTY using bash
1283	1299		\\ Commands are passed as-is: do not wrap in quotes.
1284	1300		\\ Commands run sequentially: do not send multiple in parallel.
1285		-	\\ Avoid interactive programs (pagers, editors, prompts): they hang.
1286		-	\\
1287		-	\\ If the command hangs, send Ctrl+C to recover:
1288		-	\\ zmx run <session> $(printf '\x03')
1289		-	\\
1290		-	\\ If the command hangs, print the history to see the error:
1291		-	\\ zmx history <session> \| tail -100
	1301	+	\\ Stdin is redirected from /dev/null to prevent interactive programs
	1302	+	\\ (pagers, editors, prompts) from blocking. Use `zmx send` for
	1303	+	\\ commands that need user input, or pipe data directly:
	1304	+	\\ echo "data" \| zmx run dev cat
1292	1305		\\
1293	1306		\\ `-d` will detach from the calling terminal. Use `wait` to track
1294	1307		\\ its status.

...	...		@@ -1297,7 +1310,8 @@ fn help() !void {
1297	1310		\\ zmx run dev ls
1298	1311		\\ zmx run dev zig build
1299	1312		\\ zmx run dev grep -r TODO src
1300		-	\\ zmx run dev git -c core.pager=cat diff
	1313	+	\\ zmx run dev git log --oneline # pager won't block
	1314	+	\\ echo "hello" \| zmx run dev cat # piped stdin still works
1301	1315		\\
1302	1316		\\ zmx run dev -d sleep 10
1303	1317		\\ zmx wait dev

Commit a25e2fe

Commit `a25e2fe`