nandi/frq · f1e99b4

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Expanded only where a Flex can hold it

"Cannot hit test a render box that has never been laid out", in a pile, and
then a failed assertion on semantics. All one cause: `hbox` renders as a Wrap,
`entry` with no width returned `Expanded`, and `Expanded` outside a Flex fails
the layout — after which every box under it is asked to hit-test without ever
having been laid out. The chats screen has two unsized entries in an `hbox`,
which is where it fired.

The renderer now threads the axis it is building into, because there is no way
to ask Flutter after the fact. An unsized entry takes the rest of the row where
there is a row and a definite width otherwise; a `fillHeight` vbox and a
`scroll` expand only into a Flex. A TextField has no intrinsic width, so in a
Wrap it was both illegal and unmeasurable, which is why one field took the
whole screen down rather than just itself.

A row whose child asks to fill the height now stretches on its cross axis,
which is where that has to come from — Expanded in a Row is about width.

FRQ_AUTOCONNECT comes back with it, deleted along with the spike it was written
for. It is how this was found at all: the connect screen is clean because its
entries carry widths, so a window that only ever reaches that screen looks
fine. A Wayland window cannot be clicked from a script, and sitting in front of
one is not a check.

Not yet verified past the connect screen — that is the next thing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

nandi committed 2026-09-18T23:30:44-07:00 Browse files

f1e99b4 parent: 2e24e64

modified flutter/lib/nim_renderer.dart +50 -15 Viewed

@@ -134,9 +134,30 @@ class _NimAppState extends State<NimApp> {
134	134
135	135	// ------------------------------------------------------------------ build
136	136
137		- Widget _build(core.UiNode n) {
138		- final kids = n.children.map(_build).toList();
	137	+ /// The axis of the widget a node is being built into, because `Expanded`
	138	+ /// is only legal inside a Flex and there is no way to ask Flutter after the
	139	+ /// fact.
	140	+ ///
	141	+ /// Getting this wrong is what "Cannot hit test a render box that has never
	142	+ /// been laid out" means, in a pile: an `Expanded` inside a `Wrap` fails the
	143	+ /// layout, and every box under it is then asked to hit-test without ever
	144	+ /// having been laid out. The chats screen did exactly that — two unsized
	145	+ /// entries in an `hbox`, which is a Wrap.
	146	+ static const _noAxis = '';
	147	+ static const _row = 'row';
	148	+ static const _column = 'column';
	149	+
	150	+ Widget _build(core.UiNode n, [String axis = _noAxis]) {
139	151	final spacing = _d(n.props['spacing'], 0);
	152	+ final flex = axis == _row \|\| axis == _column;
	153	+
	154	+ // What this node's own children are being built into.
	155	+ final childAxis = switch (n.tag) {
	156	+ 'page' \|\| 'vbox' \|\| 'card' \|\| 'scroll' \|\| 'dialog' => _column,
	157	+ 'hbox' => n.prop('wrap', true) ? _noAxis : _row,
	158	+ _ => _noAxis,
	159	+ };
	160	+ final kids = n.children.map((c) => _build(c, childAxis)).toList();
140	161
141	162	switch (n.tag) {
142	163	case 'page':
@@ -166,8 +187,11 @@ class _NimAppState extends State<NimApp> {
166	187	final w = _d(n.props['widthRequest'], 0);
167	188	if (w > 0) col = SizedBox(width: w, child: col);
168	189	// `fillHeight` is what keeps the compose bar at the bottom instead
169		- // of wherever the backlog happens to end.
170		- return n.prop('fillHeight', false) ? Expanded(child: col) : col;
	190	+ // of wherever the backlog happens to end — but only a Flex can be
	191	+ // told to expand into.
	192	+ return (n.prop('fillHeight', false) && flex)
	193	+ ? Expanded(child: col)
	194	+ : col;
171	195	}
172	196
173	197	case 'hbox':
@@ -179,12 +203,18 @@ class _NimAppState extends State<NimApp> {
179	203	final wrapping = n.prop('wrap', true);
180	204	final align = n.prop('align', 'center');
181	205	if (!wrapping) {
	206	+ // A child asking to fill the height gets it from the row's cross
	207	+ // axis, not from an Expanded — Expanded in a Row is about width.
	208	+ final stretches =
	209	+ n.children.any((c) => c.prop('fillHeight', false));
182	210	return _margins(
183	211	n,
184	212	Row(
185		- crossAxisAlignment: align == 'end'
186		- ? CrossAxisAlignment.end
187		- : CrossAxisAlignment.center,
	213	+ crossAxisAlignment: stretches
	214	+ ? CrossAxisAlignment.stretch
	215	+ : (align == 'end'
	216	+ ? CrossAxisAlignment.end
	217	+ : CrossAxisAlignment.center),
188	218	children: _spaced(kids, spacing, vertical: false),
189	219	),
190	220	);
@@ -475,10 +505,15 @@ class _NimAppState extends State<NimApp> {
475	505	onSubmitted: (_) => _send(n.prop('onSubmit', '')),
476	506	);
477	507	final w = _d(n.props['widthRequest'], 0);
478		- // A width request is a minimum in the screens' vocabulary, but here
479		- // it has to be a maximum too: an unconstrained TextField inside a
480		- // Wrap has no width at all to take.
481		- return w > 0 ? SizedBox(width: w, child: field) : Expanded(child: field);
	508	+ if (w > 0) return SizedBox(width: w, child: field);
	509	+ // No width asked for: take the rest of the row where there is a row
	510	+ // to take it from, and otherwise a definite width. NOT Expanded
	511	+ // unconditionally — a TextField has no intrinsic width, so in a Wrap
	512	+ // it is both illegal and unmeasurable, and that combination is what
	513	+ // took the whole screen down rather than one field.
	514	+ return axis == _row
	515	+ ? Expanded(child: field)
	516	+ : SizedBox(width: 320, child: field);
482	517	}
483	518
484	519	case 'scroll':
@@ -493,10 +528,10 @@ class _NimAppState extends State<NimApp> {
493	528	body = Scrollbar(child: body);
494	529	final h = _d(n.props['height'], 0);
495	530	if (h > 0) return SizedBox(height: h, child: body);
496		- // No fixed height: take what the column has left. `reserve` is the
497		- // Clojure's way of saying the same thing to a backend that could not
498		- // do this, and is ignored here on purpose.
499		- return Expanded(child: body);
	531	+ // No fixed height: take what the column has left, where there is a
	532	+ // column. `reserve` is the Clojure's way of saying the same thing to
	533	+ // a backend that could not do this, and is ignored here on purpose.
	534	+ return flex ? Expanded(child: body) : SizedBox(height: 400, child: body);
500	535	}
501	536
502	537	/// A panel over the screen rather than a screen of its own.

    // ------------------------------------------------------------------ build
--  Widget _build(core.UiNode n) {
++  /// The axis of the widget a node is being built *into*, because `Expanded`
--    final kids = n.children.map(_build).toList();
++  /// is only legal inside a Flex and there is no way to ask Flutter after the
++  /// fact.
++  ///
++  /// Getting this wrong is what "Cannot hit test a render box that has never
++  /// been laid out" means, in a pile: an `Expanded` inside a `Wrap` fails the
++  /// layout, and every box under it is then asked to hit-test without ever
++  /// having been laid out. The chats screen did exactly that — two unsized
++  /// entries in an `hbox`, which is a Wrap.
++  static const _noAxis = '';
++  static const _row = 'row';
++  static const _column = 'column';
++
++  Widget _build(core.UiNode n, [String axis = _noAxis]) {
      final spacing = _d(n.props['spacing'], 0);
++    final flex = axis == _row || axis == _column;
++
++    // What this node's own children are being built into.
++    final childAxis = switch (n.tag) {
++      'page' || 'vbox' || 'card' || 'scroll' || 'dialog' => _column,
++      'hbox' => n.prop('wrap', true) ? _noAxis : _row,
++      _ => _noAxis,
++    };
++    final kids = n.children.map((c) => _build(c, childAxis)).toList();
      switch (n.tag) {
        case 'page':
            final w = _d(n.props['widthRequest'], 0);
            if (w > 0) col = SizedBox(width: w, child: col);
            // `fillHeight` is what keeps the compose bar at the bottom instead
--          // of wherever the backlog happens to end.
++          // of wherever the backlog happens to end — but only a Flex can be
--          return n.prop('fillHeight', false) ? Expanded(child: col) : col;
++          // told to expand into.
++          return (n.prop('fillHeight', false) && flex)
++              ? Expanded(child: col)
++              : col;
          }
        case 'hbox':
            final wrapping = n.prop('wrap', true);
            final align = n.prop('align', 'center');
            if (!wrapping) {
++            // A child asking to fill the height gets it from the row's cross
++            // axis, not from an Expanded — Expanded in a Row is about width.
++            final stretches =
++                n.children.any((c) => c.prop('fillHeight', false));
              return _margins(
                n,
                Row(
--                crossAxisAlignment: align == 'end'
++                crossAxisAlignment: stretches
--                    ? CrossAxisAlignment.end
++                    ? CrossAxisAlignment.stretch
--                    : CrossAxisAlignment.center,
++                    : (align == 'end'
++                        ? CrossAxisAlignment.end
++                        : CrossAxisAlignment.center),
                  children: _spaced(kids, spacing, vertical: false),
                ),
              );
              onSubmitted: (_) => _send(n.prop('onSubmit', '')),
            );
            final w = _d(n.props['widthRequest'], 0);
--          // A width request is a minimum in the screens' vocabulary, but here
++          if (w > 0) return SizedBox(width: w, child: field);
--          // it has to be a maximum too: an unconstrained TextField inside a
++          // No width asked for: take the rest of the row where there is a row
--          // Wrap has no width at all to take.
++          // to take it from, and otherwise a definite width. NOT Expanded
--          return w > 0 ? SizedBox(width: w, child: field) : Expanded(child: field);
++          // unconditionally — a TextField has no intrinsic width, so in a Wrap
++          // it is both illegal and unmeasurable, and that combination is what
++          // took the whole screen down rather than one field.
++          return axis == _row
++              ? Expanded(child: field)
++              : SizedBox(width: 320, child: field);
          }
        case 'scroll':
            body = Scrollbar(child: body);
            final h = _d(n.props['height'], 0);
            if (h > 0) return SizedBox(height: h, child: body);
--          // No fixed height: take what the column has left. `reserve` is the
++          // No fixed height: take what the column has left, where there is a
--          // Clojure's way of saying the same thing to a backend that could not
++          // column. `reserve` is the Clojure's way of saying the same thing to
--          // do this, and is ignored here on purpose.
++          // a backend that could not do this, and is ignored here on purpose.
--          return Expanded(child: body);
++          return flex ? Expanded(child: body) : SizedBox(height: 400, child: body);
          }
        /// A panel over the screen rather than a screen of its own.

modified nim/src/frq/reducer.nim +23 -1 Viewed

@@ -11,7 +11,7 @@
11	11	## payload: the alternative is a second serialisation to define and version,
12	12	## for arguments that are always one string.
13	13
14		-import std/[json, options, sequtils, strutils, tables]
	14	+import std/[json, options, os, sequtils, strutils, tables]
15	15	import std/sets
16	16	import frq/[cells, model, rooms, reactions, edits, trace, ircparse, clock,
17	17	atproto, handshake]
@@ -426,3 +426,25 @@ proc drain*() =
426	426
427	427	else:
428	428	trace("skip", p.command & " " & $p.params)
	429	+
	430	+
	431	+# -------------------------------------------------------------- autoconnect
	432	+#
	433	+# `FRQ_AUTOCONNECT=1` presses Connect on the first render, and `FRQ_NICK`
	434	+# overrides the nickname. In the same spirit as FRQ_TRACE and for the same
	435	+# reason: a GUI on Wayland cannot be clicked from a script, so without this the
	436	+# only way to check that the window gets past the connect screen is to sit in
	437	+# front of it — which is not a check, and is how a layout error on the chats
	438	+# screen went unnoticed while the connect screen looked fine.
	439	+
	440	+var autoconnectDone = false
	441	+
	442	+proc maybeAutoconnect*() =
	443	+ if autoconnectDone: return
	444	+ autoconnectDone = true
	445	+ let want = getEnv("FRQ_AUTOCONNECT")
	446	+ if want.len == 0 or want == "0": return
	447	+ let nick = getEnv("FRQ_NICK")
	448	+ if nick.len > 0: app.formNick = nick
	449	+ trace("auto", "FRQ_AUTOCONNECT set — connecting as " & app.formNick)
	450	+ connectNow()

  ## payload: the alternative is a second serialisation to define and version,
  ## for arguments that are always one string.
--import std/[json, options, sequtils, strutils, tables]
++import std/[json, options, os, sequtils, strutils, tables]
  import std/sets
  import frq/[cells, model, rooms, reactions, edits, trace, ircparse, clock,
             atproto, handshake]
      else:
        trace("skip", p.command & " " & $p.params)
++
++
++# -------------------------------------------------------------- autoconnect
++#
++# `FRQ_AUTOCONNECT=1` presses Connect on the first render, and `FRQ_NICK`
++# overrides the nickname. In the same spirit as FRQ_TRACE and for the same
++# reason: a GUI on Wayland cannot be clicked from a script, so without this the
++# only way to check that the window gets past the connect screen is to sit in
++# front of it — which is not a check, and is how a layout error on the chats
++# screen went unnoticed while the connect screen looked fine.
++
++var autoconnectDone = false
++
++proc maybeAutoconnect*() =
++  if autoconnectDone: return
++  autoconnectDone = true
++  let want = getEnv("FRQ_AUTOCONNECT")
++  if want.len == 0 or want == "0": return
++  let nick = getEnv("FRQ_NICK")
++  if nick.len > 0: app.formNick = nick
++  trace("auto", "FRQ_AUTOCONNECT set — connecting as " & app.formNick)
++  connectNow()

modified nim/src/frq_core.nim +1 -0 Viewed

@@ -151,6 +151,7 @@ proc frq_conn_event*(): cstring {.exportc, dynlib.} =
151	151	# crossing are a tree going out and an event id coming back.
152	152
153	153	proc currentTree(): string =
	154	+ maybeAutoconnect()
154	155	## Whichever screen the state says. `drain` first, so the tree Dart gets is
155	156	## built after every line that had arrived when it asked — that is the whole
156	157	## of the polling model, and why there is no callback into Dart.

  # crossing are a tree going out and an event id coming back.
  proc currentTree(): string =
++  maybeAutoconnect()
    ## Whichever screen the state says. `drain` first, so the tree Dart gets is
    ## built after every line that had arrived when it asked — that is the whole
    ## of the polling model, and why there is no callback into Dart.