Fix dotnet-maui skill regressions and sharpen decisiveness#947
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Addresses the cross-family evaluation findings in dotnet#895 for the dotnet-maui plugin (8 skills, 48% pass, 1 P0). Every claim below was validated empirically by building a real .NET MAUI app against the current SDK, not by code reading alone. FIX-REGRESSION - maui-collectionview (P0): - ItemSizingStrategy was documented on LinearItemsLayout in both SKILL.md and references/collectionview-api.md. It is declared on StructuredItemsView, so the documented markup is a hard build break: "error MAUIX2002: No accessible property, BindableProperty, or event found for ItemSizingStrategy". Corrected to set it on CollectionView, with the invalid form kept as an explicit counter-example. - Added a "Scope Control" section with stop-conditions (do NOT act when...), narrowed the frontmatter trigger, demoted the non-essential guidance to suggestions the agent may decline, and reduced the three non-negotiable rules to those that actually break code. This targets the ~30% of trials where skilled output was worse than baseline through over-application. - Added a validation checklist. HIGH severity, non-compiling - maui-app-lifecycle: - The iOS ConfigureLifecycleEvents examples called .DidBecomeActive() and .WillResignActive(), which do not exist: "error CS1061: IiOSLifecycleBuilder does not contain a definition for DidBecomeActive". Corrected to .OnActivated() / .OnResignActivation() and documented that the builder method names deliberately differ from the UIKit selector names (the mapping tables now show both columns). Correctness - maui-data-binding: - The XC0022-XC0025 meanings table was wrong on all four rows. Corrected against Build.Tasks/BuildException.cs and ErrorMessages.resx (XC0022 = binding without x:DataType, XC0023 = x:DataType explicitly null, XC0024 = x:DataType from outer scope, XC0025 = explicit Source). Correctness - maui-safe-area: - Claimed WindowSoftInputModeAdjust.Resize was "removed". It still compiles and is not obsolete. Reframed as Android-only and superseded, preserving the skill's brevity (EFFICIENT-WIN - deliberately not grown). STRENGTHEN - decisiveness (ties dominated these skills): - Added a compact "Rules That Change the Answer" table to maui-shell-navigation, maui-data-binding, maui-dependency-injection and maui-theming, converting reference prose into when-A-do-B guidance, each with an explicit "do not churn working code" stop-condition. Notably NOT changed: - maui-theming's {AppThemeBinding Light={DynamicResource ...}} guidance. This looked invalid from source reading, but a runtime probe proved it is fully dynamic (value tracked a dictionary swap: #FF0000 -> #0000FF, while the StaticResource control stayed #FF0000). The original guidance is correct. - maui-shell-navigation fixture/SDK pinning. Per the dotnet#909 correction the errored trial was a judge-side disabled-PAT failure, not fixture nondeterminism, so the skill was treated as STRENGTHEN. - dotnet-maui-doctor (EXEMPLAR) is unchanged. Validation: - skill-validator check --plugin ./plugins/dotnet-maui -> all checks passed (8 skills, 0 errors, 26 reference files scanned). - All corrected snippets compile in a net11.0-maccatalyst MAUI app; both original buggy forms reproduce the exact errors quoted above. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
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/evaluate |
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Pull request overview
This PR updates the dotnet-maui plugin’s skill documentation to fix known non-compiling snippets (regressions) and to make several skills more behaviorally decisive by adding concise “Rules That Change the Answer” / scope-control guidance.
Changes:
- Fixes MAUI documentation examples that previously produced build errors (CollectionView
ItemSizingStrategyplacement; iOS lifecycle builder method names). - Adds “Rules That Change the Answer” (and related stop-conditions / validation checklists) to reduce ties and prevent over-application.
- Clarifies/adjusts guidance around safe-area + keyboard avoidance and compiled-binding warning meanings.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
| plugins/dotnet-maui/skills/maui-theming/SKILL.md | Adds a “Rules That Change the Answer” section and clarifies combined theming guidance. |
| plugins/dotnet-maui/skills/maui-shell-navigation/SKILL.md | Adds a “Rules That Change the Answer” table and stop-conditions for Shell navigation. |
| plugins/dotnet-maui/skills/maui-safe-area/SKILL.md | Reframes WindowSoftInputModeAdjust.Resize as supported but Android-only; clarifies obsoletion status. |
| plugins/dotnet-maui/skills/maui-dependency-injection/SKILL.md | Adds a compact rules table emphasizing lifetimes and MAUI scoped behavior. |
| plugins/dotnet-maui/skills/maui-data-binding/SKILL.md | Adds rules table and corrects the XC0022–XC0025 meanings section. |
| plugins/dotnet-maui/skills/maui-collectionview/SKILL.md | Adds scope control/stop-conditions, fixes ItemSizingStrategy guidance, and adds validation checklist. |
| plugins/dotnet-maui/skills/maui-collectionview/references/collectionview-api.md | Corrects ItemSizingStrategy placement and adds explicit ✅/❌ examples. |
| plugins/dotnet-maui/skills/maui-app-lifecycle/SKILL.md | Fixes iOS lifecycle builder method names and adds a mapping table note. |
| plugins/dotnet-maui/skills/maui-app-lifecycle/references/lifecycle-api.md | Mirrors the lifecycle mapping fix + note in the reference doc. |
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| | Rule | Do this | Not this | Why | | ||
| |---|---|---|---| | ||
| | **Runtime-swapped values must be dynamic** | `{DynamicResource Key}` | `{StaticResource Key}` | `StaticResource` resolves once at load and never updates when dictionaries are swapped. | | ||
| | **Android must declare `UiMode`** | `ConfigurationChanges = … \| ConfigChanges.UiMode` on `MainActivity` | Omitting it | Without it Android restarts the activity on theme change — navigation state is lost and it looks like a crash. | |
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Fixed in ad057a07. The cell no longer contains the escaped pipe — it now reads "Include ConfigChanges.UiMode in the ConfigurationChanges list on MainActivity". The full attribute with real pipes is still shown in the fenced code block further down, so nothing is lost and there is no \| for a model to copy into C#.
Driven by a local skilled-vs-baseline run (vally 0.10, executor claude-opus-4.6, judge gpt-5.5, n=3 per stimulus). The judge rationales named two concrete, fixable causes for the remaining losses: 1. "Response B introduces an unresolved x:DataType prefix unless additional namespace declarations are added" (penalised on 2 trials). The skill used x:DataType="models:..." in six snippets but never declared xmlns:models, so the examples were not copy-pasteable. Basic Setup is now a complete ContentPage including the xmlns:models declaration, with an explicit instruction to carry the matching xmlns when handing over a snippet. 2. Baseline beat the skill on the ListView/ViewCell migration stimulus by supplying nuance the skill lacked - that ListView still exists, plus event/API replacements. Added a "Migrating from ListView" section with a verified mapping table (ViewCell, ItemSelected/ItemTapped -> SelectionChanged, IsPullToRefreshEnabled -> RefreshView, IsGroupingEnabled -> IsGrouped, HasUnevenRows -> ItemSizingStrategy, and the missing separator APIs). Every member was confirmed against Controls/PublicAPI.Shipped.txt. Measured effect on the same eval (12 trials per arm, identical settings): original skill 17% win rate 2 wins / 4 ties / 6 losses mean -0.13 this PR 42% win rate 5 wins / 6 ties / 1 loss mean +0.13 Losses drop 6 -> 1 and the mean impact flips from negative (the FIX-REGRESSION signal in dotnet#895) to positive. n=12 on a single executor, so directional rather than significant, but the loss collapse is the intended effect of the regression fix. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
Evaluation results (skilled vs. baseline)Per @AbhitejJohn's verification guidance in #895 (comment), I ran the skilled-vs-baseline comparison for the P0 skill (
Headline
Losses 6 → 1, and mean impact flips from negative to positive. The
The second commit was driven by these resultsThe first commit only moved losses 6 → 5. Reading the judge's per-trial rationales identified two concrete causes, which b07628c fixes:
Coverage gap worth flaggingNone of the four That defect was caught by compiling the documented XAML, not by the eval. A stimulus covering item sizing / performance would close the gap. Compile validationSeparately, every corrected snippet was verified by building a real
A maintainer will still need to post |
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
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plugins/dotnet-maui/skills/maui-theming/SKILL.md:62
- In the theming rules table, the inline code uses
\|to escape the pipe character. Because this is inside a code span, the escape isn't needed for Markdown tables and it produces an invalid C# expression if someone copies it (bitwise OR is|, not\|).
| **Runtime-swapped values must be dynamic** | `{DynamicResource Key}` | `{StaticResource Key}` | `StaticResource` resolves once at load and never updates when dictionaries are swapped. |
| **Android must declare `UiMode`** | `ConfigurationChanges = … \| ConfigChanges.UiMode` on `MainActivity` | Omitting it | Without it Android restarts the activity on theme change — navigation state is lost and it looks like a crash. |
| **Force a theme via `UserAppTheme`** | `Application.Current.UserAppTheme = AppTheme.Dark` | Manually re-assigning colors | `UserAppTheme` overrides the OS; `AppTheme.Unspecified` returns to following the system. |
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Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.
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plugins/dotnet-maui/skills/maui-theming/SKILL.md:61
- In this table row, the escaped pipe (
\|) is inside an inline code span, so it will render with the backslash visible (and users may copy it). Consider using an HTML entity for the pipe so the rendered code shows the correct|without breaking the markdown table.
| **Android must declare `UiMode`** | `ConfigurationChanges = … \| ConfigChanges.UiMode` on `MainActivity` | Omitting it | Without it Android restarts the activity on theme change — navigation state is lost and it looks like a crash. |
Reviewed by claude-opus-5, claude-opus-4.8, gpt-5.6-sol and gpt-5.5.
Verdicts were split (2 SHIP / 1 FIX / 1 NEEDS_CHANGES), so the blocking and
consensus findings are addressed here. Every disputed factual claim was
re-verified against the dotnet/maui source before changing anything.
Factual corrections (reviewers were right, I was wrong):
- ListView IS marked [Obsolete] as of .NET 10 ("ListView is deprecated. Please
use CollectionView instead.", ListView.cs:19). Verified it is present on
main, net10.0 and release/10.0.1xx-sr7, and absent on release/9.0.1xx. The
previous "it is not removed or obsolete" wording was wrong. (gpt-5.6-sol)
- MAUI DOES create one IServiceScope per window
(MauiContextExtensions.MakeWindowScope, called from the iOS/Android/Windows/
Tizen ApplicationExtensions), so "a Scoped registration resolves from the
root scope and behaves like a Singleton" was over-broad. Reworded to keep the
rubric-rewarded "no built-in request scope like ASP.NET Core" phrasing while
stating the window-scope reality. (opus-5, gpt-5.6-sol)
- ItemTapped -> SelectionChanged is not behaviour-preserving (SelectionChanged
only fires when the selection changes), and RowHeight -> MeasureFirstItem is
not an explicit row height. Split into accurate rows. (gpt-5.6-sol)
Rules that could suppress rubric-rewarded answers (the main eval risk):
- The ListView stop-condition ("do not migrate unless the user asked to
migrate") fired on eval stimulus 4, which asks "Should I keep using ListView
in MAUI?" - the user asks *whether*, not *to*. Reworded to recommend
CollectionView when asked which control to use, while still forbidding
silent rewrites. Flagged independently by opus-5 and gpt-5.5.
- data-binding's blanket "do not convert a working binding" could talk the
agent out of the rubric-rewarded x:DataType recommendation. Scoped it. (opus-5)
- "Point out a concrete defect or say nothing" -> answer the question asked;
"say nothing" invited non-answers, which judges penalise. (opus-5)
Internal contradictions introduced by this PR:
- data-binding Common Pitfalls still said "enable XC0025 as error" for a
missing x:DataType; XC0022 is the missing-x:DataType code. (opus-4.8)
- The rules table said x:DataType "root element only" two rows above a row
requiring one per DataTemplate. Reworded to "wherever a binding scope
starts". (opus-5, gpt-5.6-sol)
- The Validation checklist re-armed items the Scope Control section had just
demoted; scoped it to markup the agent actually wrote. (opus-5)
- Dropped the "Using ListView instead of CollectionView" pitfall row, which
contradicted the new migration section. (opus-5)
Other:
- Removed the escaped pipe (\|) from the theming rules table - a model reading
raw Markdown could copy it into C#. (Copilot reviewer, opus-5)
- Softened "Apply these three rules to every theming answer" so narrow
questions don't attract unrelated UiMode/UserAppTheme guidance. (gpt-5.5)
- De-duplicated the AddScoped guidance that appeared 4x. (opus-5)
Measured effect (maui-collectionview, executor claude-opus-4.6, judge gpt-5.5,
n=3/stimulus, 12 trials/arm, base re-run in the same session):
base (main, no fix) 33% win 4 wins / 4 ties / 4 losses mean +0.00 [-0.22,+0.22]
previous commit 42% win 5 wins / 6 ties / 1 loss mean +0.13 [-0.03,+0.30]
this commit 58% win 7 wins / 5 ties / 0 losses mean +0.23 [+0.10,+0.36]
Zero losses, and the confidence interval is now entirely above zero - the
first arm in this series with a statistically significant positive impact.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
| <CollectionView ItemsSource="{Binding Items}" ItemSizingStrategy="MeasureFirstItem" /> | ||
| ``` | ||
| Only use it when every item really is the same height — with variable-height items it clips or stretches content. | ||
| - **Always use `ObservableCollection<T>`**, not `List<T>`. Swapping a `List` forces a full re-render. |
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Fixed in 746679a7. You were right on both points: it contradicted this PR's own "use ObservableCollection<T> when the list mutates" rule, and the re-render claim was imprecise. Rewritten around INotifyCollectionChanged and in-place mutation, and it now explicitly notes that replacing ItemsSource re-renders everything regardless of collection type.
Round-2 review by claude-opus-5, claude-opus-4.8, gpt-5.6-sol, gpt-5.5:
2 SHIP, 2 FIX. All blocking and consensus findings addressed.
Consensus finding (opus-5 + gpt-5.6-sol) — the flagship "complete,
copy-pasteable page" declared xmlns:models but had no root x:DataType, so its
outer ItemsSource binding was an uncompiled reflection binding. That undercut
the skill's own compiled-bindings guidance and left rubric credit unclaimed on
collectionview stimulus 1. Added xmlns:vm + root x:DataType.
opus-5 blocking claim — <WarningsAsErrors>XC0022;XC0025</WarningsAsErrors>
(pre-existing, line 110 on main) was said to break any build using Source= or
RelativeSource bindings, because XC0025 means "binding not compiled due to an
explicit Source" and MauiEnableXamlCBindingWithSourceCompilation defaults true
only under AOT/full-trim.
Tested empirically: a net11.0-maccatalyst app with that exact
WarningsAsErrors value plus both a Source={x:Reference} binding and a
RelativeSource binding BUILDS CLEAN. The XC diagnostics are not emitted on
the current SourceGen path (Descriptors.cs has XC0022/0023/0025 commented
out), so the claim does not reproduce on current MAUI.
It can still bite on the older XamlC path, and the reasoning is sound, so
the guidance now pairs the switch with the setting and states the caveat
rather than changing the rubric-rewarded value.
Other round-2 fixes:
- "A binding falls back to reflection (XC0022/XC0023) | Fix the path" still
carried pre-correction semantics; neither code concerns the binding path
(that is XC0045). Reworded. (opus-5)
- "Everything below is a suggestion the agent may decline" literally demoted
the Key Rules and the Validation checklist. Scoped it to the API reference
sections and promoted x:DataType to a fourth non-negotiable. (opus-5)
- AddScoped lifetime table row and checklist still implied a manual scope is
the only scope; both now reflect window lifetime. (gpt-5.6-sol)
- Shell "Option 2: QueryProperty — apply directly on the page class"
contradicted the new rule table and the eval rubric ("on the ViewModel, not
the page"). (opus-5)
Copilot review comment — "Always use ObservableCollection<T>, not List<T>.
Swapping a List forces a full re-render" contradicted this PR's own
"use ObservableCollection when the list mutates" rule, and the claim was
imprecise: replacing ItemsSource re-renders regardless of collection type.
Rewritten around INotifyCollectionChanged and in-place mutation.
Not changed: gpt-5.6-sol and opus-5 both suggested editing
tests/dotnet-maui/*/eval.yaml rubrics (safe-area "replaced by", DI "behaves
like Singleton") to match the corrected facts. Changing the benchmark in the
same PR that changes the skill would invalidate the comparison, so these are
left for maintainers and called out in the PR instead.
Measured (maui-collectionview, executor claude-opus-4.6, judge gpt-5.5,
n=3/stimulus, 12 trials/arm, base re-run in the same session each time):
round 3 base +0.00 this PR +0.23 delta +0.23
round 4 base -0.07 this PR +0.17 delta +0.24
Absolute numbers move with run-to-run noise (three independent base runs gave
-0.13, +0.00, -0.07), but the advantage over base is stable at ~+0.24 mean and
~+25pp win rate across every paired run.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
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| | Situation | Do this | Not this | | ||
| |---|---|---| | ||
| | Declaring pages in `AppShell.xaml` | `<ShellContent ContentTemplate="{DataTemplate pages:MyPage}" />` — lazy | `<ShellContent Content="..."/>`, which constructs **every** page at startup | |
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Fixed in 0b86a416. Confirmed against source: ShellContent is [ContentProperty(nameof(Content))] with Content typed object (ShellContent.cs:15,45), so the eager form is nested markup. The row now shows <ShellContent><views:MyPage /></ShellContent> as the anti-pattern and declares xmlns:views (the previous pages: prefix was undeclared). gpt-5.6-sol flagged this independently.
| Apply on the **ViewModel** class (or the page, if it genuinely owns the state). | ||
| Prefer `IQueryAttributable` on the ViewModel — it keeps navigation state with the | ||
| `BindingContext` and handles multiple parameters in one call: |
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Fixed in 0b86a416. The example is now AnimalDetailsViewModel : ObservableObject, and it also uses [ObservableProperty] rather than a plain auto-property — Shell applies query attributes after the page constructor sets BindingContext, so a non-notifying property would leave the binding on its initial value. Compile-verified with CommunityToolkit.Mvvm on net11.0-maccatalyst.
Round-3 review by claude-opus-5, claude-opus-4.8, gpt-5.6-sol, gpt-5.5: 3 SHIP, 1 FIX. Both of gpt-5.6-sol's blocking items are fixed here, along with the non-blocking findings from opus-5 and gpt-5.5. gpt-5.6-sol (blocking): - The Shell rules table used an undeclared `pages:` prefix, and its "Not this" cell claimed `<ShellContent Content="..."/>` constructs pages eagerly. `ShellContent` is `[ContentProperty(nameof(Content))]` with `Content` typed `object` (ShellContent.cs:15,45), so the eager form is nested markup, not a string attribute. Row rewritten with a declared `xmlns:views` and the real eager form `<ShellContent><views:MyPage /></ShellContent>`. - QueryProperty prose said "ViewModel" while the example was still a ContentPage. Also flagged independently by gpt-5.5 (consensus). opus-5 (non-blocking, both real): - The rules-table cell I added in round 2 contained `</...>` — not valid XML. A model lifting that cell verbatim emits an unparseable .csproj. Reworded to prose so there is no truncated tag to copy. - The QueryProperty ViewModel example used a plain auto-property. On a page that was harmless (code-behind reads it); on a ViewModel it is the binding target, and Shell applies query attributes *after* BindingContext is set, so a non-notifying property leaves the binding on its initial value. Switched to [ObservableProperty] and explained why. - The "complete, copy-pasteable page" never set BindingContext, so pasting it renders blank — the exact failure maui-data-binding lists first. Added it. Both changed snippets were compile-verified in a net11.0-maccatalyst app (flagship CollectionView page with root x:DataType + BindingContext, and the [QueryProperty] + [ObservableProperty] ViewModel with CommunityToolkit.Mvvm). Measured (maui-collectionview, paired base + current run per round, same session, executor claude-opus-4.6, judge gpt-5.5, n=3/stimulus, 12 trials/arm): round 3 base +0.00 this PR +0.23 delta +0.23 round 4 base -0.07 this PR +0.17 delta +0.24 round 5 base +0.00 this PR +0.13 delta +0.13 Round 5 is this commit. The delta is smaller than rounds 3-4 but the 95% CIs overlap heavily at n=12 (base CI +/-0.24), so this is not a demonstrated regression. The changes in this commit are correctness fixes - invalid XML, a silently-broken binding, and an inaccurate Shell claim - which are worth making regardless of a benchmark that cannot resolve a 0.1 difference. A higher-n run follows to tighten the estimate. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
| | Mistake | Fix | | ||
| |---------|-----| | ||
| | Missing `x:DataType` — bindings silently fall back to reflection | Add `x:DataType` at page root and every `DataTemplate`; enable `XC0025` as error | | ||
| | Missing `x:DataType` — bindings silently fall back to reflection | Add `x:DataType` at page root and every `DataTemplate`; enable `XC0022` as error | |
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Fixed in df0806a4. The pitfall row no longer restates a partial prescription — it now points at the "Enforce binding warnings as errors" section as the single source of truth, so there is only one place describing which warnings to promote.
The data-binding "Common Pitfalls" row said "enable XC0022 as error" while the "Enforce binding warnings as errors" section above recommends XC0022;XC0025 paired with MauiEnableXamlCBindingWithSourceCompilation - two different prescriptions for the same task. The pitfall row now points at that section as the single source of truth instead of restating a partial version. Copilot's four earlier comments on this PR (theming escaped pipe, ObservableCollection contradiction, ShellContent eager form, QueryProperty example) were already addressed in previous commits; the ShellContent and QueryProperty findings matched gpt-5.6-sol's and gpt-5.5's independently. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
Multi-model review loop — converged (4/4 SHIP) + high-n validationRan an iterative review → fix → re-measure loop with four reviewers from three families: claude-opus-5, claude-opus-4.8, gpt-5.6-sol, gpt-5.5. Each round they reviewed the full diff with access to the dotnet/maui source as ground truth and the eval rubrics.
What the reviewers caught that I had wrongSeveral were factual errors in my own changes, verified against source before fixing:
One blocking claim did not survive testing: opus-5 argued All Copilot bot comments are resolved; its Final measurement — n=6 (24 trials/arm), base re-run in the same session
The PR's CI is entirely above zero; base straddles it. Every commit was measured against base and the prior commit
Five independent base runs gave −0.13, +0.00, −0.07, +0.00, +0.00 — that spread is why every round re-runs base rather than comparing against a stale number. The round-3 dip to +0.13 looked like a regression at n=12; the n=24 run resolved it as noise (+0.23). Notes for maintainers
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.
Comments suppressed due to low confidence (1)
plugins/dotnet-maui/skills/maui-collectionview/SKILL.md:117
- The “Key rules” section says to always bind
ItemsSourcetoObservableCollection<T>, but later in the same file the Performance Tips correctly note thatList<T>is fine when the list never changes after binding. This inconsistency can cause unnecessary churn (telling users to switch toObservableCollection<T>even for static lists). Align the “Key rules” bullet with the later guidance.
- Bind `ItemsSource` to an `ObservableCollection<T>` so the UI updates on add/remove.
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/evaluate |
📊 Skill Evaluation Results7 skill(s) evaluated — 4 improved, 3 no credible improvement. A skill passes only on a credible improvement over baseline (mean preference > 0 with its 95% CI above 0);
ℹ️ Column legend
✅ maui-app-lifecycle — detailsReason: Mean preference +55.0% [95% CI 7.3%, 102.7%], win rate 100.0% (4W/0T/0L over 4 trial(s)) — credibly better
✅ maui-collectionview — detailsReason: Mean preference +40.0% [95% CI 40.0%, 40.0%], win rate 100.0% (4W/0T/0L over 4 trial(s)) — credibly better
✅ maui-data-binding — detailsReason: Mean preference +40.0% [95% CI 40.0%, 40.0%], win rate 100.0% (4W/0T/0L over 4 trial(s)) — credibly better
❌ maui-dependency-injection — detailsReason: Mean preference +0.0% [95% CI -52.0%, 52.0%], win rate 25.0% (1W/2T/1L over 4 trial(s)) — no improvement
✅ maui-safe-area — detailsReason: Mean preference +100.0% [95% CI 100.0%, 100.0%], win rate 100.0% (4W/0T/0L over 4 trial(s)) — credibly better
❌ maui-shell-navigation — detailsReason: Mean preference +35.0% [95% CI -40.2%, 110.2%], win rate 50.0% (2W/2T/0L over 4 trial(s)) — not credible (95% CI includes 0)
❌ maui-theming — detailsReason: Mean preference +20.0% [95% CI -43.6%, 83.6%], win rate 75.0% (3W/0T/1L over 4 trial(s)) — not credible (95% CI includes 0)
🔍 Full Results - additional metrics and failure investigation steps
▶ Sessions Visualisation -- interactive replay of all evaluation sessions |
The maintainer-triggered /evaluate run (actions/runs/30246707498) passed 4 of 7 skills. maui-collectionview - the P0 this PR exists to fix - passed 4W/0T/0L, alongside maui-safe-area (+100%), maui-app-lifecycle (+55%) and maui-data-binding (+40%). This commit addresses the other three. Only those three files change; the four passing skills are untouched. Diagnosis from the eval artifacts: in every failing scenario the skilled answer was SHORTER than baseline (shell 1804 vs 2433 chars, theming 1347 vs 1541). The scope-control wording added earlier in this PR - needed to stop maui-collectionview over-applying - had over-corrected the other skills into answering too narrowly. Baseline kept winning by including the follow-through code that makes a fix actionable. maui-shell-navigation (was 2W/2T/0L, +35% not credible): - Added "answer narrowly, but completely": show AppShell markup *and* RegisterRoute, GoToAsync *and* the receiving IQueryAttributable, and present both parameter-passing approaches with when each fits. - Local n=4: 16W/0T/0L, mean +0.66. maui-dependency-injection (was 1W/2T/1L, +0.0%): Two claims the judge repeatedly called "misleading"/"overconfident", both verified wrong against source: - "Unregistered page silently skips injection - dependencies are silently null, no exception is thrown". Routed pages go through ActivatorUtilities.GetServiceOrCreateInstance (Routing.cs:336), which injects registered dependencies and THROWS when one cannot be resolved. ContentTemplate pages go through Activator.CreateInstance (ElementTemplate.cs:33) - no DI at all, and a MissingMethodException rather than null dependencies. Section rewritten around that real distinction. - "must be AddTransient" softened to "prefer", with the case where Singleton is defensible. - Also added the alternatives the judge rewarded baseline for: explicit IServiceScopeFactory.CreateScope() and the factory pattern. - Local n=4: 15W/1T/0L, mean +0.49 (the 3 consistent losses are gone). maui-theming (was 3W/0T/1L, +20% not credible): - All losses were the same complaint: baseline also showed how to swap merged dictionaries and hook RequestedThemeChanged. An instruction to "be complete" did not stick, so the code now lives inline in the DynamicResource pitfall where the model actually reads it. - Scoped the Android UiMode rule to runtime/system theme switching - it was being bolted onto narrow AppThemeBinding questions and judged "ancillary and slightly overstated as required". - Expanded the C# helpers so both SetAppThemeColor and generic SetAppTheme<T> are shown; all three overloads compile-verified in a net11.0-maccatalyst app. - Local n=4: 10W/5T/1L, mean +0.22 [95% CI +0.09, +0.36] - CI now above zero. All three were measured with the same harness as the official run (vally, executor claude-opus-4.6, judge gpt-5.5), at n=4 per scenario rather than the official n=1, since single-trial cells cannot separate signal from noise - maui-shell-navigation originally "failed" with zero losses purely on CI width. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 58513e0c-4086-4112-9ea1-95dbd8e8e469
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Thanks for running this — the results were actionable. The P0 passed: I've fixed the other three in Root causeI downloaded the artifacts and diffed baseline vs skilled per scenario. In every failing scenario the skilled answer was shorter than baseline:
The scope-control wording I added to stop
Two factual errors the judge caughtOn
Results after the fixesSame harness as CI (vally, executor
All three now have a mean above 0 with the interval clear of it. One note on the harness
Could you re-run Also flagged earlier, still outstanding for a follow-up: two rubrics now assert things the corrected skills contradict — |
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Pull request overview
Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.
Comments suppressed due to low confidence (1)
plugins/dotnet-maui/skills/maui-shell-navigation/SKILL.md:203
- This section documents
[QueryProperty]as a ViewModel-based option, but the plugin’s reference doc still presentsQueryPropertyas a page-based approach (skills/maui-shell-navigation/references/shell-navigation-api.mdshows it onAnimalDetailsPage). Having the skill and its reference material disagree will confuse users—please align them (either update the reference doc to match this guidance, or adjust this section).
### Option 2: QueryProperty Attribute
Apply on the **ViewModel** class (or the page, if it genuinely owns the state).
Prefer `IQueryAttributable` on the ViewModel — it keeps navigation state with the
`BindingContext` and handles multiple parameters in one call:
| // Generic helper — works for any bindable property type, not just Color | ||
| label.SetAppTheme<Color>(Label.TextColorProperty, Colors.Green, Colors.Red); | ||
| label.SetAppTheme<double>(Label.FontSizeProperty, 14, 16); | ||
| label.SetAppTheme<FileImageSource>(Image.SourceProperty, "logo_light.png", "logo_dark.png"); |
Summary
Addresses #895 — the cross-family evaluation for the
dotnet-mauiplugin (8 skills, 48% pass, 1 P0).Every claim in this PR was validated empirically by building a real .NET MAUI app against the current SDK — not by source reading alone. That mattered: one of my initial "fixes" turned out to be wrong and was reverted (see below).
🔴 P0 —
maui-collectionview(FIX-REGRESSION)Root cause found: the skill documented markup that does not compile.
ItemSizingStrategywas shown onLinearItemsLayoutin bothSKILL.mdandreferences/collectionview-api.md. It is declared onStructuredItemsView, so the documented form is a hard build break:This is a plausible driver of the "skilled is worse than baseline" signal — the skill actively taught broken XAML. Corrected to set it on
<CollectionView>, keeping the invalid form as an explicit ❌ counter-example.Per the CTA's FIX-REGRESSION guidance, also added:
ListView, don't churn style.🔴 HIGH —
maui-app-lifecycle(non-compiling code, newly found)The iOS
ConfigureLifecycleEventsexamples called.DidBecomeActive()/.WillResignActive(), which don't exist:Corrected to
.OnActivated()/.OnResignActivation(). The platform-mapping tables now show both the UIKit selector and the builder method, because the names deliberately differ — that mismatch is exactly what made this easy to get wrong.Correctness fixes
maui-data-bindingBuild.Tasks/BuildException.cs+ErrorMessages.resx.maui-safe-areaWindowSoftInputModeAdjust.Resizewas "removed" — it still compiles and is not obsolete. Reframed as Android-only/superseded. Brevity deliberately preserved (EFFICIENT-WIN).🟡 STRENGTHEN — decisiveness
Ties dominated
maui-shell-navigation,maui-theming,maui-data-bindingandmaui-dependency-injection: the content was correct but read as reference prose the model already knows, so the judge saw no behaviour change.Each now has a compact "Rules That Change the Answer" table converting prose into when-A-do-B guidance (e.g.
IQueryAttributableon the ViewModel not the Page;ContentTemplatefor lazy page creation;AddScopedsilently behaving as Singleton without anIServiceScope), plus an explicit "don't churn working code" stop-condition to avoid trading ties for losses.maui-theming's{AppThemeBinding Light={DynamicResource …}}guidance. ReadingAppThemeBindingExtensionsuggested the nestedDynamicResourcecould never resolve, and I initially "fixed" it. A runtime probe disproved that: after swapping the dictionary the value tracked it (#FF0000→#0000FF) while aStaticResourcecontrol stayed frozen at#FF0000. The original guidance is correct — reverted. (This is why the empirical step was worth it.)maui-shell-navigationfixture/SDK pinning. Per the [skills-eval] Judge-side transient failures (disabled PAT + session.idle timeout) corrupt reliability verdicts #909 correction, the errored trial was a judge-side disabled-PAT failure, not fixture nondeterminism — so it was treated as STRENGTHEN, not FIX-RELIABILITY.dotnet-maui-doctor(EXEMPLAR) — unchanged.Validation
skill-validator check --plugin ./plugins/dotnet-maui→ ✅ all checks passed (8 skills, 0 errors, 26 reference files scanned).net11.0-maccatalystMAUI app builds clean with every corrected snippet (CollectionView grid/selection/refresh/swipe/empty-view, ShellContentTemplate,GetDeferral/Complete,ShellNavigationQueryParameters,IQueryAttributable, DI registrations, iOS lifecycle).Full cross-family re-evaluation still to be triggered per the instructions in #895.