Saving the init file in a pane (Config) applies its settings at once; its commands are not run a second time

A setting changed in the init file took effect only at the next start.
The host's Save now hands a written init file's text back to the core,
which applies its setting lines again (each idempotent), with the same
notice and err for one that fails; a command line in it (`Newcol`)
belongs to the start and is left alone.

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

3 files changed, 27 insertions, 1 deletions

diff --git a/src/exec.zig b/src/exec.zig
index 8a24969d..722ad3de 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -980,9 +980,21 @@ pub fn executeBuiltinLine(p: *Pardes, id: usize, txt: []const u8) bool {
 }
 
 pub fn applyStartupConfig(p: *Pardes) void {
+    applyInitText(p, p.opts.startup_config orelse return, false);
+}
+
+/// The init file saved in a pane: its settings applied again. Only its
+/// setting lines: a command in it (`Newcol`) is the session's start, and
+/// would not be right twice.
+pub fn reapplyInitFile(p: *Pardes, path: []const u8, text: []const u8) void {
+    const init_path = p.opts.startup_config_path orelse return;
+    if (!std.mem.eql(u8, init_path, path)) return;
+    applyInitText(p, text, true);
+}
+
+fn applyInitText(p: *Pardes, text: []const u8, settings_only: bool) void {
     p.announce = false;
     defer p.announce = true;
-    const text = p.opts.startup_config orelse return;
     // A UTF-8 BOM an editor left at its start is no part of its first word.
     const body = if (std.mem.startsWith(u8, text, "\xEF\xBB\xBF")) text[3..] else text;
     var lines = std.mem.splitScalar(u8, body, '\n');
@@ -993,6 +1005,7 @@ pub fn applyStartupConfig(p: *Pardes) void {
         // `#` starts a comment only at a line's start: a value may hold one
         // (`#ff0000`).
         if (word.len == 0 or isComment(word)) continue;
+        if (settings_only and config.Runtime.find(word[0 .. std.mem.indexOfAny(u8, word, " \t") orelse word.len]) == null) continue;
         const failures = p.fs.failures;
         const known = executeBuiltinLine(p, p.active, line);
         if (known and p.fs.failures == failures) continue;
diff --git a/src/host_io.zig b/src/host_io.zig
index a488f0f8..8ff55d74 100644
--- a/src/host_io.zig
+++ b/src/host_io.zig
@@ -2818,6 +2818,8 @@ pub fn writeFile(core: *pardes.Pardes, watches: *file_watch.Table, pane: u8, pat
     };
     var mbuf: [256]u8 = undefined;
     core.setMessage(pane, pardes.Messages.Message.stamp(&mbuf, "saved", path));
+    // The init file, saved here (Config): its settings take effect now.
+    pardes.exec.reapplyInitFile(core, path, bytes);
 }
 
 /// A Dump's write, into the DumpDir.
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 2fa0cd7e..cd8bc6c9 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -4477,3 +4477,14 @@ test "the init file reads past a BOM, and every line it fails is a notice and an
     try testing.expect(!th.logHas(p, "line 4"));
     try testing.expect(th.logHas(p, "err - init file line 5: "));
 }
+
+test "the init file saved in a pane applies its settings again, and runs none of its commands twice" {
+    const p = try Pardes.init(testing.allocator, .{ .tty_only = true, .startup_config = "Theme dusk\n", .startup_config_path = "/tmp/pardes-init-test/init" });
+    defer p.deinit();
+    const cols = p.ncol;
+    pardes.exec.reapplyInitFile(p, "/tmp/pardes-init-test/elsewhere", "Theme acme\n");
+    try testing.expectEqualStrings("dusk", p.theme().name);
+    pardes.exec.reapplyInitFile(p, "/tmp/pardes-init-test/init", "Theme acme\nNewcol\n");
+    try testing.expectEqualStrings("acme", p.theme().name);
+    try testing.expectEqual(cols, p.ncol);
+}