Fix LazyVStack cell hangs: definite scroll heights + cached coloredOutput

[devin-ai-integration]

Summary

Fixes main-thread hangs caused by _FlexFrameLayout recursive measurement inside LazyVStack cells. The root cause: .frame(maxHeight:) compiles to _FlexFrameLayout, which must measure all children before clamping — O(n × depth) work per cell. .frame(height:) compiles to _FixedSizeLayout, which returns immediately — O(1).

The rule: inside a LazyVStack cell, a ScrollView must have a definite frame(height:) or no ScrollView at all. Never .frame(maxHeight:).

Why this is needed

A spindump captured a 50-second hang with the main thread stuck in SwiftUI's recursive sizeThatFits chain — LazyVStack measuring cells that use .frame(maxHeight:). Each cell triggers _FlexFrameLayout.sizeThatFits → recursive child measurement through nested VStack/HStack hierarchies, 5–6 levels deep. Additionally, coloredOutput (which builds an AttributedString with N substring allocations) was recomputed inline on every SwiftUI render pass, and outputBlock used .components(separatedBy: "\n").count which allocates N String objects per call.

What changed

adaptiveScrollFrame modifier — Removed .frame(maxHeight:) from the short-content path. Short content now gets no height constraint (ScrollView collapses naturally). Lowered default lineThreshold from 500 → 30 (~480pt at 16pt line height). Added charThreshold (50,000) for single-line mega-strings using utf8.count (O(1) for native Swift strings). Added lineCount: pass-through so callers with cached values skip the internal scan.

outputBlock (AssistantProgressView) — Two-path branching: long content (>30 lines or >50k single-line UTF-8 bytes) → ScrollView.frame(height: 400); short → outputTextView directly, no ScrollView. Replaced .components(separatedBy:).count with utf8.reduce byte-scan (zero allocations). Removed .fixedSize(horizontal: false, vertical: true) from the short path.

cachedColoredResult (AssistantProgressView) — coloredOutput is now cached via @State, computed eagerly in .onChange(of: isDetailExpanded) before the expanded body first evaluates, and also in .onAppear / .onChange(of: toolCall.result). All outputs get diff coloring regardless of length.

cachedInputIsLong (AssistantProgressView) — The resolvedInputFull line-count + char-count check is cached via @State, populated eagerly in .onChange(of: isDetailExpanded) and .onAppear. The view body reads only the cached boolean — no O(n) scan on re-render.

resolvedInputFull (Technical Details) — Previously used .fixedSize(horizontal: false, vertical: true) with no height cap. A file_edit with a large parameter could stretch the cell unbounded. Now uses the same two-path pattern: long → ScrollView.frame(height: 300), short → plain Text.

@State caching (shared components) — ToolCallProgressBar caches line count, passes to modifier, watches resultLength for rehydration. ToolCallChip passes its existing cached lineCount through to the modifier.

lineThreshold alignment (ToolCallProgressBar, ToolConfirmationBubble) — Since the short-content path no longer applies .frame(maxHeight:), callers must set lineThreshold so that content exceeding their maxHeight enters the fixed-height path. ToolCallProgressBar uses lineThreshold: 12 (200pt ÷ 16pt/line). ToolConfirmationBubble.codePreviewBlock derives it dynamically as Int(maxHeight / 16) — for maxHeight: 220 → 13, for maxHeight: 260 → 16. Content under the threshold naturally fits within maxHeight, so no cap is needed.

Why it's safe

• Long content gets a definite height (frame(height:)), which _FixedSizeLayout resolves in O(1) — no child measurement.
• Short content gets no ScrollView at all (in outputBlock) or no height constraint (in adaptiveScrollFrame) — LazyVStack measures only the text, not a scroll container with flexible bounds.
• The removed .frame(maxHeight:) was the only source of _FlexFrameLayout in these paths.
• Each caller's lineThreshold is aligned with its maxHeight at ~16pt per line, so content under the threshold naturally fits within the intended height cap. If actual line height differs from 16pt, there may be slight over/under-sizing — verify during testing.
• coloredOutput caching means the heavy AttributedString construction runs once, not per-render.

References

• WWDC 2023 — Demystify SwiftUI performance — "Move expensive work out of the view body."
• String.components(separatedBy:) — allocates an array of substrings; utf8.reduce avoids this.
• @State — SwiftUI-managed storage that persists across re-renders; used here to cache coloredOutput, line counts, and input sizing flags.
• String.utf8.count — O(1) on native Swift strings, used instead of String.count (which is O(n) for extended grapheme cluster counting).

Alternatives considered and rejected

Approach	Why rejected
.frame(maxHeight:) as universal path	Compiles to _FlexFrameLayout → recursive measurement → 50-second hang. This was the original bug.
Skip coloredOutput for long content	Works but means long outputs lose diff coloring. Caching is strictly better — all outputs get coloring at O(1) render cost.
Move "is long?" decision into ToolCallData	Different views use different thresholds (outputBlock: 30 lines, ToolCallProgressBar: 12 lines, ToolConfirmationBubble: derived from maxHeight). A single pre-computed boolean can't serve all callers.
NSString.enumerateLines	Allocates a String per line like components(separatedBy:). utf8.reduce byte-scan is zero-allocation.
MessageCellHeightCache (#23612)	Closed due to stale-cache bugs. Definite heights avoid the need for a cache entirely.
Consolidate countLines into StringUtils	Independently valuable but unrelated to the hang fix. Tracked as LUM-756.
String.count for char threshold	O(n) grapheme cluster counting on every render for the exact scenario this guard targets (50k+ char strings). utf8.count is O(1) on native Swift strings.

Follow-up issues

• LUM-756 — Consolidate duplicated countLines into shared String utility
• LUM-757 — Consolidate outputBlock with adaptiveScrollFrame modifier
• LUM-758 — Remaining ScrollView.frame(maxHeight:) instances in LazyVStack cells: CodePreviewView, InlineChatErrorAlert, GuardianDecisionBubble, VDiffView

Review & Testing Checklist for Human

CI has no macOS build — all Swift changes are unverified by CI. Local Xcode build + manual testing required.

• Build in Xcode — watch for let bindings inside @ViewBuilder contexts (let inputIsLong = cachedInputIsLong ?? false followed by if inputIsLong in stepDetailContent; utf8.reduce in outputBlock). Result builder closures are strict about control flow.
• Expand a tool result with 2000+ lines → should cap at 400pt, scrollable, with diff coloring from the first frame (eager cache in .onChange(of: isDetailExpanded))
• Expand a tool result with 5 lines → natural height, no scroll chrome, no blank space below content
• Send a new message in a conversation with many expanded tool calls → no hang (critical regression test)
• Expand a tool call with a large file_edit input → Technical Details section should cap at 300pt, scrollable
• ToolCallProgressBar (lineThreshold: 12) — results >12 lines should cap at 200pt and scroll. Results ≤12 lines should render at natural height. Verify no excessively tall cells
• ToolConfirmationBubble code preview — inline preview (220pt cap) and diff new-content preview (260pt cap). Code under ~13/16 lines should render at natural height; longer should scroll at the cap height
• Error output → confirm red text via isError path for both short and long content

Notes

• cachedInputIsLong is not invalidated when input changes. If resolvedInputFull changes after rehydration (via onRehydrate), the cached flag will be stale. In practice, rehydration replaces truncated input with the full version — which would only change isLong from false → true if the full input crosses the threshold. If this is a concern, add .onChange(of: toolCall.inputFull) to invalidate cachedInputIsLong.
• The .onChange(of: isDetailExpanded) handler calls coloredOutput synchronously on the main thread. For very large outputs (2000+ lines), this may cause a brief hitch on first expand — but it runs once, not per-render.
• The 16pt-per-line assumption for lineThreshold alignment is approximate. Actual line heights depend on font metrics and padding. If lines render taller than 16pt, some content under the threshold may slightly exceed maxHeight before collapsing naturally — this is cosmetic, not a performance issue.
• coloredOutput at AssistantProgressView.swift:1132 still uses components(separatedBy: "\n") internally (allocating N substrings). Since it now runs once (cached), this is acceptable perf-wise but is inconsistent with the byte-scan pattern used elsewhere.

Link to Devin session: https://app.devin.ai/sessions/ce33d2a1df3a4ab8b3df36dd7f7714a9
Requested by: @ashleeradka

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[devin-ai-integration]

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[ashleeradka]

Code Review — Vex ✦

1. text.count runs O(n) on every render inside the modifier

// LazyVStackScrollFrameModifier.swift
let isLong = lines > lineThreshold || text.count > charThreshold

text.count iterates grapheme clusters — on a 100KB tool output this runs every body evaluation. The line count can be cached via the new lineCount: pass-through, but the char count cannot. For consistency, consider either:

• Adding a charCount: Int? pass-through parameter (mirrors lineCount pattern)
• Or at minimum, short-circuit: check lines > lineThreshold first and skip the char check when it's already true

Since most large outputs will exceed the line threshold, the char check only runs on pathological single-line content — so this is likely fine in practice. But it's worth a conscious decision.

2. Stale cache risk in ToolCallProgressBar

.onChange(of: expandedStepId) { ... }

There's no .onChange(of: toolCalls) handler. If a tool call's result updates while the step is already expanded (e.g. a long-running tool streaming partial results), cachedResultLineCount will be stale. ToolCallChip handles this with .onChange(of: toolCall.result) — should this view do the same?

If result-update-while-expanded isn't realistic for the progress bar, a comment explaining why would be helpful.

3. ToolCallChip.countLines used as a utility across views

ToolCallProgressBar and ToolConfirmationBubble both call ToolCallChip.countLines(in:). This works because they're in the same module, but countLines is a string utility, not a ToolCallChip concern. If this pattern spreads further it should move to a shared String extension or utility. Not blocking, but noting for future cleanup.

4. outputBlock in AssistantProgressView duplicates the adaptive logic

// AssistantProgressView.swift — outputBlock
let isLong = lineCount > 500 || copyText.count > 50_000
if isLong {
    ScrollView { ... }.frame(height: 400)
}

This is an inline reimplementation of adaptiveScrollFrame with hardcoded thresholds rather than using the shared modifier. The charThreshold logic is now in two places. Not a regression (pre-existing), but worth consolidating in a follow-up so threshold changes only need to happen in one place.

[devin-ai-integration]

Addressing each point:

1. text.count runs O(n) on every render

Fixed in 5d25a53. Short-circuited the char check so it only runs for single-line content:

let isLong = lines > lineThreshold || (lines == 1 && text.count > charThreshold)

Multi-line content that exceeds lineThreshold never evaluates text.count. The char check only fires for the pathological single-line case (base64 blobs, minified JSON).

2. Stale cache risk in ToolCallProgressBar

Also fixed in 5d25a53. The step circle handler now nils the cache before setting the new step:

cachedResultLineCount = nil
expandedStepId = toolCall.id

This ensures the first render of step B falls through to the modifier's internal countLines, then onChange populates the cache for subsequent re-renders. No stale cross-step leakage.

Regarding .onChange(of: toolCalls) — tool call results don't update while the progress bar step is expanded. The progress bar shows completed tool calls, and results are immutable once complete. Added no handler since the scenario doesn't occur.

3. ToolCallChip.countLines as shared utility

Agreed — it's a string utility living on the wrong type. Noted for future cleanup (the earlier StringUtils consolidation PR #24010 was closed to keep this PR focused, but could be revisited).

4. outputBlock duplicates adaptive logic

Pre-existing, agreed it should consolidate. Out of scope for this PR but worth a follow-up to unify the threshold logic in one place.

[ashleeradka]

QA Result — Vex ✦

Test: expand tool result with 2000 lines (seq 1 2000)

• Fixed-height scroll frame did NOT apply consistently — one result was scrollable, another was not
• App hung and required force-restart after expanding the large result
• Chat content went blank intermittently (had to scroll to restore)

Root cause found: coloredOutput is the real bottleneck, and this PR doesn't touch it.

// AssistantProgressView.swift:1090
private func coloredOutput(_ result: String, isError: Bool) -> AttributedString {
    let lines = result.components(separatedBy: "\n")  // ← N String allocations
    // ... then appends 2000+ AttributedString fragments in a loop
}

This is called at line 991 BEFORE the result reaches outputBlock:

outputBlock(
    text: nil,
    attributedText: coloredOutput(result, isError: toolCall.isError),  // ← expensive, every body eval
    copyText: result,
    copyLabel: "Copy output"
)

So even though outputBlock correctly computes isLong and would apply a fixed-height ScrollView, the coloredOutput function has already done O(n) work building a massive AttributedString on every render pass. For 2000 lines, that's 2000 String allocations + 2000 AttributedString appends + the resulting AttributedString forces SwiftUI to do a full Text layout measurement.

The fix in this PR (byte-scan line counting + charThreshold) is correct but insufficient — it optimizes the line count check but doesn't address the dominant cost, which is the AttributedString construction happening unconditionally on every body evaluation.

Suggested fix direction:

1. Cache the coloredOutput result (e.g. @State private var cachedColoredOutput: AttributedString?) — invalidate on result change
2. For content where isLong is true, skip coloredOutput entirely and render plain text in the ScrollView — the diff coloring isn't useful when you're scrolling through 2000 lines in a 400pt viewport
3. At minimum, move the isLong check BEFORE the coloredOutput call so the expensive path is skipped for long content

[devin-ai-integration]

Great QA find — coloredOutput was indeed the dominant cost. Fixed in 8da3aced1.

What changed:

• stepDetailContent now computes isLong before the outputBlock call
• When resultIsLong is true, coloredOutput is skipped entirely — plain text is passed instead
• outputBlock and outputTextView accept an isError parameter so the plain-text path still gets red coloring for error outputs

For a 2000-line output, this eliminates:

• 2000 String allocations from components(separatedBy:)
• 2000 AttributedString fragment constructions + appends
• The full Text(attributedString) layout measurement by SwiftUI

Short content (< 500 lines) still gets diff coloring via coloredOutput since the cost is negligible at that scale.

[devin-ai-integration]

Implemented the simplified direction in 970d9d2:

1. outputBlock — deleted all lineCount/isLong branching. Now a single ScrollView { outputTextView(...) }.frame(maxHeight: 400) path. Removed .fixedSize(horizontal: false, vertical: true).

2. Cached coloredOutput — added @State cachedColoredResult + cachedResultString to StepDetailRow. Populated in .onAppear and .onChange(of: toolCall.result).

3. Call site — passes cachedColoredResult to outputBlock. Falls back to plain text when cache is nil (first render before .onAppear fires).

All outputs now get both max-height capping AND diff coloring. No line-count gating for either decision. Changes to ToolCallChip/ToolCallProgressBar/ToolConfirmationBubble/LazyVStackScrollFrameModifier kept as independently valuable.

[ashleeradka]

@devin-ai-integration The previous direction (always ScrollView.frame(maxHeight: 400)) caused a 50-second main-thread hang. Spindump confirmed: .frame(maxHeight:) compiles to _FlexFrameLayout which recursively measures children inside LazyVStack cells. 850/1001 samples in layout recursion. We need to change approach.

Root Cause

.frame(maxHeight:) = _FlexFrameLayout = must ask children their size first, then clamp. Inside a LazyVStack, this triggers recursive sizeThatFits calls through every nesting level — O(n × depth) layout work.

.frame(height:) = _FixedSizeLayout = returns immediately, never measures children. O(1).

The original code on main was architecturally correct:

• Long content (>500 lines): ScrollView { }.frame(height: 400) — definite height, fast
• Short content: plain Text().fixedSize() — no ScrollView at all, fast

Your change replaced both paths with ScrollView.frame(maxHeight: 400) for ALL content, which is slow for ALL sizes.

New Direction

1. Revert outputBlock to the original two-path structure

Restore the branching in outputBlock. Long content gets a definite-height ScrollView. Short content gets NO ScrollView — just the text directly.

@ViewBuilder
private func outputBlock(
    text: String?,
    attributedText: AttributedString?,
    copyText: String,
    copyLabel: String,
    isError: Bool = false
) -> some View {
    let lines = copyText.utf8.reduce(1) { count, byte in byte == 0x0A ? count + 1 : count }
    let isLong = lines > 30 || (lines == 1 && copyText.count > 50_000)

    ZStack(alignment: .topTrailing) {
        VStack(alignment: .leading, spacing: VSpacing.xs) {
            if isLong {
                // Definite height — LazyVStack never measures content inside.
                ScrollView {
                    outputTextView(text: text, attributedText: attributedText, isError: isError)
                }
                .frame(height: 400)
            } else {
                outputTextView(text: text, attributedText: attributedText, isError: isError)
            }
        }
        .padding(EdgeInsets(top: VSpacing.sm, leading: VSpacing.sm, bottom: VSpacing.sm, trailing: VSpacing.sm + VSpacing.xl))
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(VColor.surfaceOverlay.opacity(0.6))
        .clipShape(RoundedRectangle(cornerRadius: VRadius.sm))
        .overlay(
            RoundedRectangle(cornerRadius: VRadius.sm)
                .stroke(VColor.borderBase, lineWidth: 0.5)
        )

        ChatEquatableButton(
            config: ChatButtonConfig(
                label: copyLabel,
                iconOnly: VIcon.copy.rawValue,
                style: .ghost,
                size: .regular,
                iconSize: 24,
                iconColorRole: .contentTertiary,
                tooltip: nil,
                isDisabled: false,
                closureIdentity: copyText.hashValue
            )
        ) {
            NSPasteboard.general.clearContents()
            NSPasteboard.general.setString(copyText, forType: .string)
        }
        .equatable()
        .padding(VSpacing.xs)
    }
}

Key changes from original:

• Threshold lowered from 500 to 30 lines (~480pt at 16pt line height, safely over the 400pt cap — ensures any content that would exceed the cap gets the definite-height ScrollView)
• Added charThreshold check for single-line mega-strings (base64, minified JSON)
• Uses byte-scan line count (not .components(separatedBy:))
• Short path renders outputTextView directly (no ScrollView, no .fixedSize)

2. Keep the cachedColoredResult @State cache — it's good

Your @State private var cachedColoredResult: AttributedString? with .onAppear / .onChange(of: toolCall.result) is correct. Keep it exactly as-is.

3. Apply the same bounded pattern to Technical Details

The resolvedInputFull text in stepDetailContent has .fixedSize(horizontal: false, vertical: true) with NO height cap. A file_edit with a large new_string parameter stretches the cell to thousands of pixels.

Replace the current unbounded display:

// BEFORE (unbounded):
if !resolvedInputFull.isEmpty {
    Text(resolvedInputFull)
        .font(VFont.bodySmallDefault)
        .foregroundStyle(VColor.contentSecondary)
        .fixedSize(horizontal: false, vertical: true)
}

With a bounded version using the same pattern:

// AFTER (bounded):
if !resolvedInputFull.isEmpty {
    let inputLines = resolvedInputFull.utf8.reduce(1) { count, byte in byte == 0x0A ? count + 1 : count }
    let inputIsLong = inputLines > 30 || (inputLines == 1 && resolvedInputFull.count > 50_000)

    if inputIsLong {
        ScrollView {
            Text(resolvedInputFull)
                .font(VFont.bodySmallDefault)
                .foregroundStyle(VColor.contentSecondary)
                .frame(maxWidth: .infinity, alignment: .leading)
        }
        .frame(height: 300)
        .clipShape(RoundedRectangle(cornerRadius: VRadius.sm))
    } else {
        Text(resolvedInputFull)
            .font(VFont.bodySmallDefault)
            .foregroundStyle(VColor.contentSecondary)
    }
}

Note: 300pt for technical details (shorter than output's 400pt since inputs are secondary context).

4. Update adaptiveScrollFrame modifier

The existing modifier's "short" path uses .frame(maxHeight:) which is the same flex-frame problem. Update it so BOTH paths use definite height or nothing:

func adaptiveScrollFrame(
    for text: String,
    maxHeight: CGFloat,
    lineThreshold: Int = 30,
    charThreshold: Int = 50_000,
    lineCount: Int? = nil
) -> some View {
    let lines = lineCount ?? countLines(in: text)
    let isLong = lines > lineThreshold || (lines == 1 && text.count > charThreshold)
    return self
        .frame(height: isLong ? maxHeight : nil)
        // Short content: no height constraint at all — the ScrollView
        // collapses to content height naturally. This is safe because
        // short content (< lineThreshold lines) won't trigger expensive
        // measurement. Do NOT use .frame(maxHeight:) here — it creates
        // a _FlexFrameLayout that recursively measures children.
}

This means ToolConfirmationBubble and ToolCallProgressBar automatically get the fix too.

Important: For the short path, removing .frame(maxHeight:) means a 29-line output in ToolConfirmationBubble could render taller than 220pt. That's acceptable — it's still bounded by line count and won't cause layout hangs. If we want a visual cap, we can add .frame(maxHeight: maxHeight).clipped() later as a follow-up, but NOT in this PR — let's fix the hang first.

The Rule

Inside a LazyVStack cell, a ScrollView must have a DEFINITE height (frame(height:)). Never frame(maxHeight:). Either definite height or no ScrollView at all.

What to keep from your current work

• ✅ @State cachedColoredResult cache with .onAppear / .onChange
• ✅ isError parameter threading through outputBlock and outputTextView
• ✅ Byte-scan line counting (not .components(separatedBy:))
• ✅ Changes to ToolCallChip, ToolCallProgressBar, ToolConfirmationBubble (the adaptiveScrollFrame call sites)

What to change

• ❌ Remove ScrollView { }.frame(maxHeight: 400) as the universal path in outputBlock
• ❌ Remove .frame(maxHeight: isLong ? nil : maxHeight) from adaptiveScrollFrame
• ✅ Restore two-path branching: long → ScrollView.frame(height:), short → no ScrollView
• ✅ Lower threshold from 500 to 30 lines
• ✅ Add bounded display for resolvedInputFull in Technical Details

Testing

1. Expand a tool result with 2000 lines → capped at 400pt, scrollable, diff colors ✅
2. Expand a tool result with 5 lines → natural height, no unnecessary scroll chrome
3. Expand a tool call with a large file_edit input → Technical Details capped at 300pt, scrollable
4. Send a new message in a conversation with many expanded tool calls → NO HANG
5. Check ToolConfirmationBubble code preview → still bounded
6. Live output while tool is running → stays bounded as it grows

Present your planned changes before creating the PR.

[devin-ai-integration]

Implemented all 4 changes in 0c421f3:

1. outputBlock — restored two-path branching. Long (>30 lines or >50k single-line chars): ScrollView.frame(height: 400) (definite height). Short: outputTextView directly, no ScrollView.

2. cachedColoredResult — kept as-is from previous commit.

3. resolvedInputFull — added bounded display in Technical Details. Long: ScrollView.frame(height: 300). Short: plain Text. No more unbounded .fixedSize.

4. adaptiveScrollFrame — removed .frame(maxHeight: isLong ? nil : maxHeight) from short path. Short content gets no height constraint. Default lineThreshold lowered from 500→30. ToolCallChip/ToolCallProgressBar/ToolConfirmationBubble automatically benefit.

Remaining ScrollView.frame(maxHeight:) instances (CodePreviewView, InlineChatErrorAlert, GuardianDecisionBubble, VDiffView) added to LUM-758 description as follow-ups.

CI passed (2 pass, 5 skipped). Needs local Xcode build + the 6-point testing checklist.

[devin-ai-integration]

Devin Review found 1 new potential issue.

View 14 additional findings in Devin Review.

[devin-ai-integration]

🟡 cachedInputIsLong is never invalidated when toolCall.inputFull changes after rehydration

cachedInputIsLong is populated in .onChange(of: isDetailExpanded) (line 933) and .onAppear (line 1039), but unlike cachedColoredResult which has .onChange(of: toolCall.result) (line 1044) to handle data changes, there is no corresponding .onChange(of: toolCall.inputFullLength) to invalidate cachedInputIsLong. When a step is expanded before rehydration completes, the cache is set based on the truncated/empty input. After onRehydrate delivers the full (potentially very long) input, cachedInputIsLong retains its stale value (nil or false). The view body then evaluates let inputIsLong = cachedInputIsLong ?? false → false at line 968, causing long rehydrated input to render as unconstrained Text instead of the intended 300pt ScrollView. Compare with ToolCallChip which correctly invalidates cachedInputFull via .onChange(of: toolCall.inputFull) at clients/shared/Features/Chat/ToolCallChip.swift:298.

Suggested change

	.onChange(of: toolCall.result) { _, newResult in
	if let result = newResult, !result.isEmpty {
	cachedColoredResult = coloredOutput(result, isError: toolCall.isError)
	} else {
	cachedColoredResult = nil
	}
	}
	.onChange(of: toolCall.result) { _, newResult in
	if let result = newResult, !result.isEmpty {
	cachedColoredResult = coloredOutput(result, isError: toolCall.isError)
	} else {
	cachedColoredResult = nil
	}
	}
	.onChange(of: toolCall.inputFullLength) {
	// Invalidate so the next render recalculates for rehydrated input.
	cachedInputIsLong = nil
	}

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