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ADR 0025: Command line + :compile + output panel

Status

Accepted

Context

Phase 15 of the "complete normal editor" plan. Two design questions were resolved with the user before implementing, both confirmed exactly as proposed:

  1. The : command line joins the FloatingPanel family established in ADR 0022 — same centered/flat/animated treatment as Find/Replace and Open/Save-As, since it's the same "glance, act, dismiss" interaction shape.
  2. The output panel deliberately does not — it's docked at the bottom of the window instead. Find/Replace/Open/Save-As/the command line are all quick, modal, and fine to float centered over your code because you're not looking at the code while they're open. The output panel is different: you want to watch a build stream while still looking at, and jumping back into, your code. A centered overlay would fight that.

Decision

AseProcess (core/include/ase/process.h, core/src/process.c)

Extracted from the LSP client's existing (previously file-local, duplicated-in-spirit-if-this-phase-hadn't-happened) platform_spawn/ platform_read_nonblocking/platform_write_all/platform_terminate — same fork/exec/pipe/SIGPIPE-handling code, same POSIX-real/ Windows-stub split (ADR 0011 decision 6: ase_process_spawn returns NULL cleanly on Windows rather than shipping untested async I/O). Two additions beyond a straight extraction, both needed for :compile specifically (the LSP client never needed either): - cwd parameter: the child chdir()s before execvp (and refuses to run, _exit(127), if that fails — running a build in the wrong directory is actively misleading, not a case to silently ignore). - stderr merged into the same stream as stdout (dup2 onto both fds) — compiler errors go to stderr; a build tool's output panel that only shows stdout would silently miss most of what you actually want to see, so v1 doesn't attempt to split them. - ase_process_has_exited/ase_process_exit_code: a non-blocking waitpid(..., WNOHANG) check, cached once true. The LSP client never needed this (it tracks liveness via read EOF/error instead, its own alive flag) but :compile needs the real exit code to report.

lsp_client.c is now a consumer of this module — its struct holds one AseProcess *process instead of child_pid/read_fd/write_fd separately, and every call site updated accordingly. Verified this refactor didn't change LSP behavior: the full existing ase_lsp_client_tests suite (handshake through shutdown, against the fake LSP server fixture) still passes unmodified. New core/tests/test_process.c covers the module directly: stdout capture, non-zero exit codes, cwd, a full write→read round trip through cat, and the execvp-fails-in-the-child case (spawn still succeeds, exit code 127).

CommandLine (gui/src/command_line.{h,cpp})

A FloatingPanel with one ":" LetterBadge and one field — the smallest member of this family, matching FindBar's shape almost exactly. : opens it (checked via the produced character in keyPressEvent, not a keycode — : is a shifted key on most layouts, and Qt has no layout-independent "colon" key). Enter reads the typed text, closes the panel, and calls EditorViewport::runCommand — kept in that order (close before running) so a command that itself touches focus or opens another panel isn't fighting the command line's own close animation. Escape cancels without running anything. No history, no buttons, no tab-completion — v1 stays exactly as small as FindBar was.

EditorViewport::runCommand dispatches on the trimmed text: w → save(), q → window()->close(), compile → compile(), output → toggles the output panel's visibility. Anything else is a silent no-op — matches the plugin host's existing "skip, don't crash" tolerance (ADR 0009) rather than an error message for a typo.

:compile (EditorViewport::compile/pollCompile)

Reads build_command from config fresh on every call (not cached, same hot-reload spirit as everything else config-driven here) — no default value (ase_config_create_default doesn't set it), matching the config's own "don't guess" convention already established for optional settings. Unconfigured, no open file, or a build already running are each reported as a line in the output panel, not a crash or a silent no-op — you asked for something to happen, so something visible happens even when it's "can't do that, here's why."

%f is substituted for the current file's path; the process runs via /bin/sh -c "<substituted command>", not execvp'd directly — the config key is documented (and the starter template's own example shows) as a shell command, so &&/pipes/etc. need real shell interpretation. cwd is the file's directory. pollCompile() is driven by a QTimer (100ms, same non-blocking-poll shape ase_lsp_client_poll already established), draining whatever's available into the output panel each tick and appending an [exit code N] line once ase_process_has_exited — at which point the process is destroyed and the timer stopped.

OutputPanel (gui/src/output_panel.{h,cpp})

Deliberately not a FloatingPanel — see Context above. A plain QWidget holding one read-only QPlainTextEdit, added as a real QVBoxLayout row in main.cpp below EditorViewport (which now needs a wrapper QWidget as the window's central widget again, this time for a genuine layout reason rather than the one Phase 13 briefly had and Phase 13.5 reverted). Starts hidden until the first :compile; :output toggles it after. Themed with the editor's own plain background/text colors, not the translucent panel_background tone floating chrome uses — it's a docked extension of the window, not an overlay, so it should read as part of the editor rather than chrome sitting on top of it.

Consequences

Verified live via xdotool: the command line opens centered with the same look as FindBar; :compile against a real build_command (echo "compiling %f"; sleep 0.5; echo "done") streams the command line, both echo outputs, and [exit code 0] into the output panel, which appears docked below the editor text, correctly themed; :w saves; :output toggles without incident. core's test suite grew by one file (test_process.c) and stayed green throughout the lsp_client.c refactor (9/9 passing, up from 8/8 — the new suite, not a regression fix).

Not built: stdout/stderr aren't separated (documented above, a deliberate v1 simplification, not a half-built feature); no ANSI color parsing in the output panel; no click-to-jump from a compiler error line to that location in the buffer; no command history or tab- completion in the command line. Vim mode is next per the roadmap, now that Phase 15 — the last item before it — is done; it gets its own dedicated planning pass, per the standing direction, rather than being scoped here.