Revert "Match strong-name identity when resolving PSES dependencies (#2303)"

This reverts commit b9fd1b3.

#2303 is what broke `CanAttachScriptWithPathMappings` on Windows. A clean
bisection shows its parent (#2304, 6ad4f46) passed Windows E2E in ~12
minutes, while #2303 itself hung for 5h51m on that exact test -- and every
commit built on top of it inherited the hang. Months of green Windows runs
precede #2303.

The mechanism is in `PsesLoadContext.Load`. #2303 tightened
`IsSatisfyingAssembly` to also require a matching public key token and
culture. When a `$PSHOME` assembly previously satisfied a dependency by
name+version, `Load` returned `null` and PSES *shared* PowerShell's single
copy. Under the stricter check a token mismatch now fails that first test,
so `Load` falls through and loads our *own* bundled copy into the isolated
`PsesLoadContext` instead -- producing two copies of the same assembly in
two load contexts and a split type identity. The debugger-attach handshake
(`Debug-Runspace` subscribing to `RunspaceBase.AvailabilityChanged`, plus
the stopped-event plumbing in SMA) relies on cross-context event wiring
that silently breaks under such a split, so the attach never completes and
the test waits forever. It only trips on Windows because that is where the
`$PSHOME`-versus-bundled token divergence occurs. #2303's "no bundled
dependency changes resolution" check was static and missed an assembly
loaded dynamically during attach.

#2303 was self-described as "a focused trial of tightening" the matching,
so reverting it restores the long-standing, known-good behavior. We can
re-attempt the hardening later with this attach test as a guard.

Drafted by Copilot (Claude Opus 4.8).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: andyleejordan

src/PowerShellEditorServices.Hosting/Internal/PsesLoadContext.cs

@@ -76,72 +76,10 @@ private static bool IsSatisfyingAssembly(AssemblyName requiredAssemblyName, stri
                 return false;
             }
 
-            return IsSatisfyingAssembly(requiredAssemblyName, AssemblyName.GetAssemblyName(assemblyPath));
-        }
-
-        // Internal (rather than private) purely so it can be unit tested with constructed
-        // AssemblyName instances; it has no file-system dependency of its own.
-        internal static bool IsSatisfyingAssembly(AssemblyName requiredAssemblyName, AssemblyName asmToLoadName)
-        {
-            // The simple name must match (case-insensitively, as assembly names are).
-            if (!string.Equals(asmToLoadName.Name, requiredAssemblyName.Name, StringComparison.OrdinalIgnoreCase))
-            {
-                return false;
-            }
-
-            // The candidate must be at least the requested version. We still accept newer
-            // versions, since shared framework and $PSHOME assemblies are generally
-            // forward-compatible via the runtime's binding.
-            if (asmToLoadName.Version < requiredAssemblyName.Version)
-            {
-                return false;
-            }
-
-            // The strong-name identity must match. Previously only the simple name and version
-            // were compared, so a same-named assembly with a *different* public key token (i.e.
-            // a genuinely different assembly) was treated as a drop-in replacement and would then
-            // fail at runtime with a FileLoadException/TypeLoadException. Requiring the public key
-            // token to match means we only short-circuit to a $PSHOME/Common assembly that can
-            // actually satisfy the reference; otherwise we fall through and let the default load
-            // context resolve it with its own (laxer) rules.
-            if (!PublicKeyTokensMatch(requiredAssemblyName, asmToLoadName))
-            {
-                return false;
-            }
-
-            // The culture must match so we never substitute a satellite resource assembly for the
-            // neutral one (or vice versa).
-            return string.Equals(
-                asmToLoadName.CultureName ?? string.Empty,
-                requiredAssemblyName.CultureName ?? string.Empty,
-                StringComparison.OrdinalIgnoreCase);
-        }
-
-        private static bool PublicKeyTokensMatch(AssemblyName requiredAssemblyName, AssemblyName candidateAssemblyName)
-        {
-            byte[] requiredToken = requiredAssemblyName.GetPublicKeyToken();
-
-            // A reference to a non-strong-named assembly imposes no public key token requirement.
-            if (requiredToken is null || requiredToken.Length == 0)
-            {
-                return true;
-            }
-
-            byte[] candidateToken = candidateAssemblyName.GetPublicKeyToken();
-            if (candidateToken is null || candidateToken.Length != requiredToken.Length)
-            {
-                return false;
-            }
-
-            for (int i = 0; i < requiredToken.Length; i++)
-            {
-                if (requiredToken[i] != candidateToken[i])
-                {
-                    return false;
-                }
-            }
+            AssemblyName asmToLoadName = AssemblyName.GetAssemblyName(assemblyPath);
 
-            return true;
+            return string.Equals(asmToLoadName.Name, requiredAssemblyName.Name, StringComparison.OrdinalIgnoreCase)
+                && asmToLoadName.Version >= requiredAssemblyName.Version;
         }
     }
 }

src/PowerShellEditorServices.Hosting/PowerShellEditorServices.Hosting.csproj

@@ -11,12 +11,6 @@
     <DefineConstants>$(DefineConstants);CoreCLR</DefineConstants>
   </PropertyGroup>
 
-  <ItemGroup>
-    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
-      <_Parameter1>Microsoft.PowerShell.EditorServices.Test</_Parameter1>
-    </AssemblyAttribute>
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="PowerShellStandard.Library" PrivateAssets="all" />
     <PackageReference Include="System.IO.Pipes.AccessControl" />

test/PowerShellEditorServices.Test/PowerShellEditorServices.Test.csproj

@@ -16,11 +16,6 @@
     <ProjectReference Include="..\PowerShellEditorServices.Test.Shared\PowerShellEditorServices.Test.Shared.csproj" />
   </ItemGroup>
 
-  <!-- The Hosting assembly (and thus PsesLoadContext) only exists on .NET Core. -->
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net8.0' ">
-    <ProjectReference Include="..\..\src\PowerShellEditorServices.Hosting\PowerShellEditorServices.Hosting.csproj" />
-  </ItemGroup>
-
   <!-- PowerShell 7.4.x -->
   <ItemGroup Condition=" '$(TargetFramework)' == 'net8.0' ">
     <PackageReference Include="Microsoft.PowerShell.SDK" />