fix(display): stable per-display keys so refresh/HDR/resolution prefs stop resetting#32
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… stop resetting Per-display settings were keyed by the monitor's DevicePath, which Windows sometimes reports empty (capture cards, some HDMI/TV targets, transient driver state). When that happened, the code minted a fresh default DisplayPreference under the fallback key (FriendlyName|GdiDeviceName) — silently resetting saved settings, e.g. a Fixed 240 Hz refresh target back to "Maximum". This also left duplicate entries behind (the same monitor saved under two keys). - Add DisplayPreferenceResolver: resolves a display's prefs by StableKey and, on a miss, reuses an existing entry for the same physical monitor by re-keying it — but only when the label maps to exactly one active monitor, so two identical panels never share a pref block. Falls back to a default otherwise. - Add DedupeDisplays migration: collapses value-identical duplicate entries (keeping the real DevicePath key), run from ConfigStore.Load so old configs self-heal. - Wire the resolver into RefreshRateMonitor, HdrMonitor, ResolutionMonitor and SettingsWindow.LoadDisplays. - Harden the Fixed-Hz target: always include the saved FixedHz in the Settings dropdown even when the panel is momentarily capped low, so opening Settings during a driver glitch can't drop the target. - Add DisplayPreferenceResolverTests (7 cases). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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| foreach (var kv in displays) | ||
| { | ||
| if (kv.Value is null || kv.Value.DisplayLabel != label) continue; | ||
| if (activeKeys.Contains(kv.Key)) continue; // belongs to another active display | ||
| if (matchKey is not null) { ambiguous = true; break; } | ||
| matchKey = kv.Key; | ||
| } |
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| foreach (var sameValue in byValue) | ||
| { | ||
| var entries = sameValue.ToList(); | ||
| if (entries.Count < 2) continue; // nothing to collapse | ||
|
|
||
| var canonical = PickCanonical(entries.Select(e => e.Key)); | ||
| foreach (var e in entries) | ||
| if (!string.Equals(e.Key, canonical, StringComparison.Ordinal)) | ||
| displays.Remove(e.Key); | ||
| } |
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| foreach (var e in entries) | ||
| if (!string.Equals(e.Key, canonical, StringComparison.Ordinal)) | ||
| displays.Remove(e.Key); |
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Problem
Per-display settings (refresh rate, HDR, resolution) are keyed by the monitor's
DevicePath. Windows sometimes reports that empty — capture cards, some HDMI/TV targets, or transient driver state — and the code then minted a fresh defaultDisplayPreferenceunder the fallback key (FriendlyName|GdiDeviceName). Effects:This is also the latent risk behind the refresh-rate-notification gap: a panel temporarily capped low by a driver glitch could lose its Fixed target.
Changes
DisplayPreferenceResolverResolve(...): on a key miss, reuses an existing entry for the same physical monitor by re-keying it onto the currentStableKey— only when the label maps to exactly one active monitor, so two identical panels never share a pref block. Falls back to a default otherwise.DedupeDisplays(...): collapses value-identical duplicate entries (keeps the real DevicePath key). Run fromConfigStore.Load, so existing configs self-heal.RefreshRateMonitor,HdrMonitor,ResolutionMonitor, andSettingsWindow.LoadDisplays.FixedHzis always included in the Settings dropdown even when the panel is momentarily capped low, so opening Settings during a glitch can't drop it.DisplayPreferenceResolverTests(7 cases — exact hit, DevicePath-disappeared re-key, unknown display, identical-monitor ambiguity, dedupe collapse, dedupe-keeps-differing).Verification
dotnet build— 0 warnings (TreatWarningsAsErrors), 0 errors.dotnet test— 114 passed, 0 failed.🤖 Generated with Claude Code