get on a pane with unsaved edits refuses once, as acme's does

A ctl get threw unsaved text away at once. acme's get asks winclean first (exec.c:513): warned once, the same get again discards. A pane dirty only because it was renamed has no text to lose, and is not asked about.

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

2 files changed, 22 insertions, 1 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 16935f41..363524f1 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -454,6 +454,7 @@ pub fn writePane(p: *Pardes, req: Req, pane: *Pane) Reply {
             if (apply and p.paneBySerial(serial) == null) return Reply.fail(req.tag, E.NOENT);
             if (std.mem.eql(u8, line, "get")) {
                 if (!apply) continue;
+                if (getRefused(p, pane)) |said| return tree.failText(req.tag, E.IO, said);
                 const errno = get(p, pane);
                 if (errno != 0) return Reply.fail(req.tag, errno);
             } else if (std.mem.eql(u8, line, "lock")) {
@@ -477,6 +478,21 @@ pub fn writePane(p: *Pardes, req: Req, pane: *Pane) Reply {
 
 const e_not_locked = "window not locked by this open";
 
+/// acme's get asks winclean first (exec.c:513): unsaved text is warned
+/// about once, and the same get again, nothing edited since, discards it.
+fn getRefused(p: *Pardes, pane: *Pane) ?[]const u8 {
+    const f = pane_files.fileOf(pane) orelse return null;
+    if (!panes.Output.fileTraits(f.output).saves or f.revision == f.saved_revision) return null;
+    // Dirty by a rename alone is no text to lose: only edits are asked about.
+    const saved = f.saved_hash orelse return null;
+    if (std.hash.Wyhash.hash(0, f.content) == saved) return null;
+    if (pane.discard_warned) |w| if (w.revision == f.revision and w.by == .get) return null;
+    pane.discard_warned = .{ .revision = f.revision, .by = .get };
+    const said = std.fmt.bufPrint(&p.fs.ename, "{s}: Modified (get again to discard)", .{f.path}) catch "Modified (get again to discard)";
+    p.setMessage(p.paneBySerial(pane.serial).?, said);
+    return said;
+}
+
 fn get(p: *Pardes, pane: *Pane) u16 {
     const f = pane_files.fileOf(pane) orelse return 0;
     if (!panes.Output.fileTraits(f.output).saves) return 0;
@@ -487,6 +503,7 @@ fn get(p: *Pardes, pane: *Pane) u16 {
     panes.File.pushUndo(p, pane);
     panes.File.setContent(p, f, bytes);
     f.saved_revision = f.revision;
+    f.saved_hash = std.hash.Wyhash.hash(0, f.content);
     return 0;
 }
 
@@ -960,6 +977,10 @@ test "get reloads the pane from disk and reports a missing file without losing d
 
     _ = wr(p, Node.of(serial, .name), try std.fmt.bufPrint(&name, "{s}/missing.txt\n", .{directory}));
     _ = wr(p, Node.of(serial, .body), "unsaved\n");
+    // Unsaved text is asked about once, as acme's get asks winclean.
+    const asked = wr(p, ctl_node, "get\n");
+    try testing.expectEqual(E.IO, asked.errno());
+    try testing.expect(std.mem.endsWith(u8, asked.reply.ename, ": Modified (get again to discard)"));
     try testing.expectEqual(E.NOENT, wr(p, ctl_node, "get\n").errno());
     try testing.expect(p.paneBySerial(serial) != null);
     try testing.expectEqualStrings("from disk\nunsaved\n", pane.file.?.content);
diff --git a/src/panes.zig b/src/panes.zig
index 8049da4e..a7e5c668 100644
--- a/src/panes.zig
+++ b/src/panes.zig
@@ -25,7 +25,7 @@ pub const EditText = struct { text: []u8, row0: i32 };
 
 pub const Pane = struct {
     /// The words that throw unsaved text away (builtins.zig warnModified).
-    pub const Discarding = enum { Exit, Restore };
+    pub const Discarding = enum { Exit, Restore, get };
 
     /// One mouse selection (block-shaped), per button. c/r are text-area relative;
     /// r counts from the tag's first row (the body starts at Pane.tag_rows).