test: generate the twins and one ProbeContext with the shapes (WS2)

.claude/probe-axes.md

@@ -69,6 +69,13 @@ and `GeneratedHarnessTests` in the conventions tests holds each file to its app'
   and one passed, so a check that did not apply voids no other; the ledger credits each passing check with the
   axes it read and the row's, never a pair put together from two checks. A seed naming an obligation is caught
   only by a check naming it.
+- Two-sided checks: the twin is `Entry.Plain`, the wrapped type at the value object's nullability (a class value object over a
+  struct faces the struct made nullable; the closed set faces a string), written by `shapes.cs` beside the value object. Build both
+  sides with `Sides.Twins(position, containing, entry, plain, vo)`, which puts the row's position and containing type around each and
+  throws, a harness error, where the two do not hold the same shape. Under `json.TypeInfoResolver=source-generated-context` the options
+  resolve through `ProbeContext` alone, which lists every shape, position and containing type and each twin, with no reflection behind
+  it; `json.TypeInfoResolverChain=context-then-default` puts the reflection fallback after it. A shape the context does not list is a
+  harness error, never a fallback (tools/probe/generators/README.md, "The twin and the context").
 - EF probes: SQLite in memory (`Data Source=:memory:` with the connection held open). PostgreSQL needs
   a server and is out of reach.
 - Analyzer probes (what compiles and what CMTK reports): in `test/CodoMetis.TypeKit.Analyzers.Tests`,

test/CodoMetis.TypeKit.Conventions.Tests/GeneratedHarnessTests.cs

@@ -29,14 +29,13 @@ public sealed class GeneratedHarnessTests
     /// </summary>
     private static readonly (string File, string App, string[] Arguments)[] Generators =
     [
-        ("Shapes.g.cs", "shapes.cs", ["--axes", Axes]),
+        ("Shapes.g.cs", "shapes.cs", ["--axes", Axes, "--l06", $"{Rows}/L06OffTheWireProbe.json.gz"]),
         ("Containers.g.cs", "containers.cs", ["--axes", Axes]),
         ("EfShapes.g.cs", "ef.cs", ["catalogue", .. EfCatalogue]),
         ("EfShapes3.g.cs", "ef.cs", ["top-level", .. EfCatalogue]),
         ("EfShapes4.g.cs", "ef.cs", ["nested", .. EfCatalogue]),
         ("KeyShapes.g.cs", "ef.cs", ["keys", "--rows", $"{Rows}/E04IntegerKeyProbe.json.gz"]),
-        ("JsonFamilyShapes.g.cs", "json-family.cs",
-            ["contexts", "--c01", $"{Rows}/C01DecimalSpellingProbe.json.gz", "--c10", $"{Rows}/C10PreserveGuardProbe.json.gz", "--l06", $"{Rows}/L06OffTheWireProbe.json.gz"]),
+        ("JsonFamilyShapes.g.cs", "json-family.cs", ["stand-ins"]),
         ("L05Shapes.g.cs", "json-family.cs", ["l05", "--rows", $"{Rows}/L05EqualityProbe.json.gz"]),
         ("C09Shapes.g.cs", "decls.cs", ["C09", "--rows", $"{Rows}/C09BaseRecordEqualityProbe.json.gz"]),
         ("C11Shapes.g.cs", "decls.cs", ["C11", "--rows", $"{Rows}/C11ParseShapesBuildProbe.json.gz"]),

tools/probe/corpus/claims.json

@@ -725,15 +725,6 @@
             "json.ReferenceHandler=IgnoreCycles"
           ]
         ]
-      },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
       }
     ]
   },
@@ -855,15 +846,6 @@
             "json.ReferenceHandler=IgnoreCycles"
           ]
         ]
-      },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
       }
     ]
   },
@@ -957,15 +939,6 @@
             "json.ReferenceHandler=IgnoreCycles"
           ]
         ]
-      },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
       }
     ]
   },
@@ -6591,15 +6564,6 @@
             "json.ReferenceHandler=IgnoreCycles"
           ]
         ]
-      },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
       }
     ]
   },
@@ -6654,15 +6618,6 @@
             "json.ReferenceHandler=IgnoreCycles"
           ]
         ]
-      },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
       }
     ]
   },
@@ -11747,15 +11702,6 @@
           ]
         ]
       },
-      {
-        "reason": "System.Text.Json refuses adding resolvers to TypeInfoResolverChain once a JsonSerializerContext is the TypeInfoResolver (JsonRow notes it as substituted, STJ refused it), so the strict context never runs with the chain.",
-        "pairs": [
-          [
-            "json.TypeInfoResolver=source-generated-context",
-            "json.TypeInfoResolverChain=context-then-default"
-          ]
-        ]
-      },
       {
         "reason": "Not promised (a-closed-set-is-a-string-enum): a closed set wraps nothing and is described as the string enum of its names, so it has no underlying type's schema to equal; the probe notes closed-set-differs.",
         "pairs": [

tools/probe/corpus/harness/ComposedProbes.cs

@@ -49,7 +49,7 @@ public static class ComposedClaims
         var obligations = Aspect.Answer.Append(Rule).Concat(Aspect.Doc).SelectMany(of).Distinct().ToList();
         WebApplication? app = null; Exception? down = null;
         try { app = await Hx.Start(r, en, Cfg(r)); }
-        catch (Exception ex) { down = ex; }
+        catch (Exception ex) when (ex is not Sides.InputsNotEquivalent) { down = ex; }
         await using var _ = app;
         string? failed = null;
         if (down is not null)
@@ -144,7 +144,7 @@ public static class ComposedClaims
         };
         WebApplication? app = null;
         try { app = await Hx.Start(r, en, cfg); }
-        catch (Exception ex)
+        catch (Exception ex) when (ex is not Sides.InputsNotEquivalent)
         {
             return ex.ToString().Contains(unmapped) ? null : $"host refused to start but not naming {unmapped}: {ex.GetType().Name}: {Cut(ex.Message)}";
         }

tools/probe/corpus/harness/DecimalSpelling.cs

@@ -67,9 +67,8 @@ sealed record Form(string Name, string Json, Exception? Ep, Exception? Ev, List<
         JsonConverter conv = number ? new DecimalNumberJsonConverter() : new DecimalStringJsonConverter();
         var position = r["shape.position"];
         var containing = position == "root" ? "class" : r["shape.containing"];
-        var hp = Pos.Build(position, containing, e, false, d);
-        var hv = Pos.Build(position, containing, e, true, Make.Vo(e, d));
-        var o = JCtx.Apply(r, e, C01JsonContext.Default, hp.Declared, hv.Declared);
+        var (hp, hv) = Sides.Twins(position, containing, e, d, Make.Vo(e, d));
+        var o = JCtx.Apply(r, e, hp.Declared, hv.Declared);
         var ob = new JsonSerializerOptions(o);      // the baseline: the same options, the serializer's own decimal
         foreach (var c in ob.Converters.Where(c => c.CanConvert(typeof(decimal))).ToList()) ob.Converters.Remove(c);
         o.Converters.Insert(0, conv);               // registered first: an application converter for decimals (own-for-wrapped) comes after it

tools/probe/corpus/harness/FaultClaim.cs

@@ -229,32 +229,15 @@ static void Walk(IEndpointRouteBuilder? b, MGrp g, Decl[] above, string prefix,
         return (eps, cfg);
     }
 
-    const string Listed = "the probes' source-generated context (ProbeContext) lists value objects at root and as a property of a class only";
-
-    /// <summary>
-    /// Under json.TypeInfoResolver=source-generated-context the payload's shape moves to one the context lists (as a property of a class),
-    /// so the strict context applies and its pairs with the fault axes are earned; JsonRow would otherwise fall back to reflection for the
-    /// whole row. NodaTime.Instant is listed nowhere and keeps JsonRow's fallback. The pairs of the strict context with the other positions
-    /// and containers are left uncovered: a limit of this harness, not a refusal of the product, so claims.json excludes none of them.
-    /// </summary>
-    static Row StrictContext(Row r)
-    {
-        if (!r.Is("json.TypeInfoResolver", "source-generated-context") || r["shape.wrapped"] == "NodaTime.Instant") return r;
-        if (r["shape.position"] is not ("root" or "property")) { r = r.With("shape.position", "property"); r.Substituted("shape.position", "property", Listed); }
-        if (r.Get("shape.containing") is not (null or "class")) { r = r.With("shape.containing", "class"); r.Substituted("shape.containing", "class", Listed); }
-        return r;
-    }
-
     public static async Task<string?> Run(Row r, Spec s)
     {
-        r = StrictContext(r);
         var en = Registry.Of(r); Process(r, en);
         var resp = Resp.Of(r);
         var (eps, cfg) = Plan(r, s, resp);
         if (eps.Count == 0) return "harness: the row maps no endpoint of the claim (an excluded pair?)";
         WebApplication? app = null; Exception? down = null;
         try { app = await Hx.Start(r, en, cfg); }
-        catch (Exception ex) { down = ex; }
+        catch (Exception ex) when (ex is not Sides.InputsNotEquivalent) { down = ex; }
         await using var _ = app;
         Baseline Against(string o) => s.Refusals.Contains(o) ? Baseline.Refusal : s.Against;
         string? failed = null;
@@ -342,7 +325,9 @@ static Row StrictContext(Row r)
             await using var app = await Hx.Start(r, en, alone);
             await Hx.Doc(app);
         }
-        catch (Exception ex) when (ex.GetType() == withTypeKit.GetType() && ex.Message == withTypeKit.Message)
+        // the same refusal, at another byte of each document (Hx.Unplaced: the two differ in length by what AddTypeKit() wrote; rows 73 and
+        // 157 of C06's regenerated rows, a char under WriteAsString)
+        catch (Exception ex) when (ex.GetType() == withTypeKit.GetType() && Hx.Unplaced(ex.Message) == Hx.Unplaced(withTypeKit.Message))
         {
             r.Note(NoteKeys.DocRefusedByAspnetAlone, ex.GetType().Name);
             return null;