From d89c0b532df23ed5b48495f83725893d5d82042b Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Thu, 3 Sep 2026 15:39:43 -0300 Subject: errors: a save that could not happen, and two panics on an ordinary click MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A review of what this program does when the environment says no. The finding that reframes it: there were almost NO panics on ordinary paths — the rule already held — but there was a great deal of silence, and one case worse than any panic. SILENT DATA LOSS ON SAVE. `saveFile` marked the pane saved the moment it QUEUED the effect, before any host had tried; `host_io.writeFd` returned void, so a short or failed write was indistinguishable from a complete one; and `writeFileBytes` returned true regardless. A save to a read-only file, or into a directory removed under the pane, therefore cleared the tag's ` *` and posted nothing — and `Del` makes no dirty check, so the next click threw the edits away with the screen saying they were safe. On a full disk it was worse: the file is already `O_TRUNC`'d when `write` fails, so the message row said `saved` over a file that had just been emptied. Now: `writeFd` reports, `writeFileBytes` returns WHY (`PermissionDenied`, `NoSpaceLeft`, `ReadOnlyFilesystem`, …) including a failed `close`, which is where write-back filesystems report at all; the core marks the pane saved around `perform` rather than at emit, which is also where the bytes are read; and a host that could not write calls `Pardes.saveFailed`, which puts the reason on the message row and takes the clean mark back. That is a CALL and not a return value because host.zig enforces, at comptime, that a `push_` method reaching every host in a fan-out cannot have one answer — the first attempt at this changed the signature and the compiler was right to refuse it. TWO PANICS ON AN ORDINARY KEYSTROKE, in look.zig's number scans. `v = v * 10 + d` over caller-supplied digits, reached from `parsePathLine` and the `@pN` scan — which every Look, every right-click and every n/N motion runs on whatever word is under the pointer. A hash in a log, a CSV column, any output shaped `foo:99999999999999999999`, and the editor died with "integer overflow". Both saturate now, the same way acmefs.zig's address parser already did; a saturated line is refused by `file_pane.open`'s `line <= total` and a saturated pane id by `focusPaneLine`'s `id < MAX_PANES`, so nothing addressable changes. A BOOT FILE THAT WILL NOT OPEN joins the missing-name case in the `+Errors` pane instead of taking the launch down: `pardes /root` resolves as a `.file`, could not be read, and left `error: PermissionDenied` and a return trace. `look.readFile` now says which errno it was, so the pane can say "permission denied" rather than a word from the source code. The tag-marker test drained no effects and passed anyway, which is exactly the defect; it drains now. Co-Authored-By: Claude Opus 5 (1M context) Claude-Session: https://claude.ai/code/session_016Q4RATpafkwahrovHQLKRf --- src/tty/tty.zig | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'src/tty') diff --git a/src/tty/tty.zig b/src/tty/tty.zig index ca263f90..de24f289 100644 --- a/src/tty/tty.zig +++ b/src/tty/tty.zig @@ -1352,7 +1352,7 @@ const Shell = struct { fn ptyWrite(ctx: ?*anyopaque, pane: u8, bytes: []const u8) void { const s = of(ctx); - if (s.ptys[pane]) |pt| host_io.writeFd(pt.file.handle, bytes); + if (s.ptys[pane]) |pt| _ = host_io.writeFd(pt.file.handle, bytes); } fn ptyResize(ctx: ?*anyopaque, pane: u8, cols: u16, rows: u16) void { @@ -1385,7 +1385,12 @@ const Shell = struct { fn writeFile(ctx: ?*anyopaque, pane: u8, path: []const u8, bytes: []const u8) void { const s = of(ctx); - if (!host_io.writeFileBytes(path, bytes)) return; + // SAY WHY, and tell the core it did not happen. A save that cannot be + // done is the one failure this program must never swallow: `saveFailed` + // puts the reason on the pane's message row and leaves the pane dirty, + // so the ` *` stays and `Del` cannot quietly take the edits. + host_io.writeFileBytes(path, bytes) catch |err| + return s.core.saveFailed(pane, "save", err); // our own write is about to come back as a watch event: restamp from // the bytes we just put there so it reads as "no change". Only when // this IS the pane's watched file — a `Save ` must not @@ -1407,7 +1412,7 @@ const Shell = struct { const s = of(ctx); var pbuf: [1024:0]u8 = undefined; const path = pardes.dump.outPath(&pbuf) orelse return; - if (!host_io.writeFileBytes(path, bytes)) return; + host_io.writeFileBytes(path, bytes) catch |err| return s.core.reportError(0, "dump", err); s.core.setLastDump(path); } -- cgit v1.3