A Python block sent to a REPL gets the second Enter that ends it

A dogfood agent's `def` sent to python3 sat open at the continuation prompt:
a block whose last line is indented is not over at one Enter, pasted into
3.13's REPL or typed into the old one (checked against python 3.14 in a real
pty, both ways). A send to a Python REPL now adds that second Enter, and the
pty/data recipe in the docs and the 9P skill says to.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

2 files changed, 17 insertions, 0 deletions

diff --git a/src/exec.zig b/src/exec.zig
index 1e9d4b2d..0c0930e2 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -464,6 +464,13 @@ fn routeToRepl(p: *Pardes, from: usize, text: []const u8) Routed {
     return .asked;
 }
 
+fn pythonBlockOpen(text: []const u8) bool {
+    const trimmed = std.mem.trimEnd(u8, text, " \t\n");
+    const start = if (std.mem.lastIndexOfScalar(u8, trimmed, '\n')) |nl| nl + 1 else 0;
+    const last = trimmed[start..];
+    return last.len > 0 and (last[0] == ' ' or last[0] == '\t' or last[last.len - 1] == ':');
+}
+
 /// Types `text` into the REPL in `to`, bracketed if its program asked for
 /// that, then Enter; says so on `from`'s message row and in the log.
 pub fn sendToRepl(p: *Pardes, from: usize, to: usize, text: []const u8) void {
@@ -491,6 +498,11 @@ pub fn sendToRepl(p: *Pardes, from: usize, to: usize, text: []const u8) void {
     }
     edit.typeToTty(p, to, dst, clean[0..n]);
     p.emitWrite(to, "\r");
+    // A Python block whose last line is indented, or a bare header, is not
+    // over at one Enter, pasted into 3.13's REPL or typed into the old one:
+    // the blank line a second Enter gives ends it.
+    if ((if (dst.repl) |r| r.lang == python_lang else false) and pythonBlockOpen(clean[0..n]))
+        p.emitWrite(to, "\r");
     // Line by line, a blank line inside a Python block ends the block.
     if (!panes.Terminal.bracketedPaste(dst) and !dst.repl_warned and (if (dst.repl) |r| r.lang == python_lang else false) and
         std.mem.indexOfScalar(u8, text, '\n') != null)
diff --git a/src/pardes.zig b/src/pardes.zig
index 239987ea..e20eb17e 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -1474,6 +1474,11 @@ test "a REPL bound for a language takes the exec made on a body in it; tags, Exe
     _ = exec.executeFrom(p, 0, "a = 1\r\nb = \x1b[201~2", true);
     Sent.drain(p);
     try std.testing.expectEqualStrings("a = 1\rb = [201~2\r", Sent.said(1));
+    // A block left open by its indented last line gets the blank line that
+    // ends it: a second Enter.
+    _ = exec.executeFrom(p, 0, "def f():\n    return 1", true);
+    Sent.drain(p);
+    try std.testing.expectEqualStrings("def f():\r    return 1\r\r", Sent.said(1));
     // Several selections executed at once: each is sent, not the first.
     {
         const text = try edit.flatSurface(p, &file.body);