michaldengusiak · Oct 15, 2026 · Oct 15, 2026 · Oct 15, 2026 · Oct 15, 2026 · Oct 15, 2026
@@ -1,4 +1,7 @@
-using Microsoft.CodeAnalysis;
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (c) 2020-2026 Michal Dengusiak & Jakub Ziolkowski and contributors
+
+using RoslynDiagnostic = Microsoft.CodeAnalysis.Diagnostic;
 using Microsoft.CodeAnalysis.CSharp.Scripting;
 using Microsoft.CodeAnalysis.Scripting;
 using System;
@@ -52,7 +55,7 @@ public async Task<MultitaskerResults> Run(IEnumerable<MultitaskerInput> multitas
 
             Script<object> script = CSharpScript.Create(code, scriptOptions, typeof(MultitaskerInput));
 
-            ImmutableArray<Diagnostic> immutableArray = script.Compile();
+            ImmutableArray<RoslynDiagnostic> immutableArray = script.Compile();
             if(immutableArray.Length != 0)
             {
                 return new MultitaskerResults(immutableArray);

@@ -1,19 +1,22 @@
-using Microsoft.CodeAnalysis;
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (c) 2020-2026 Michal Dengusiak & Jakub Ziolkowski and contributors
+
+using RoslynDiagnostic = Microsoft.CodeAnalysis.Diagnostic;
 using System;
 using System.Collections.Generic;
 
 namespace SAM.Core.Multitasker
 {
     public class MultitaskerResults
     {
-        private List<Diagnostic> diagnostics;
+        private List<RoslynDiagnostic> diagnostics;
         private List<MultitaskerResult> multitaskerResults;
 
 
-        public MultitaskerResults(IEnumerable<Diagnostic> diagnostics)
+        public MultitaskerResults(IEnumerable<RoslynDiagnostic> diagnostics)
         {
             multitaskerResults = null;
-            this.diagnostics = diagnostics == null ? null : new List<Diagnostic> (diagnostics);
+            this.diagnostics = diagnostics == null ? null : new List<RoslynDiagnostic> (diagnostics);
         }
 
         public MultitaskerResults(IEnumerable<MultitaskerResult> multitaskerResults)
@@ -29,7 +32,7 @@ public bool Succedded
             }
         }
 
-        public List<Diagnostic> Diagnostics
+        public List<RoslynDiagnostic> Diagnostics
         {
             get
             {

@@ -18,4 +18,7 @@
   <ItemGroup>
     <None Update="Rhino.Testing.Configs.xml" CopyToOutputDirectory="Always" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\SAM_Multitasker\SAM.Core.Multitasker\SAM.Core.Multitasker.csproj" />
+  </ItemGroup>
 </Project>
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (c) 2020-2026 Michal Dengusiak & Jakub Ziolkowski and contributors
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using NUnit.Framework;
+using SAM.Core.Multitasker;
+using RoslynDiagnostic = Microsoft.CodeAnalysis.Diagnostic;
+
+[TestFixture]
+public class MultitaskerDiagnosticsTests
+{
+    [Test]
+    public void PublishedDiagnosticsApiStillUsesRoslynTypes()
+    {
+        Assert.That(typeof(MultitaskerResults).GetProperty(nameof(MultitaskerResults.Diagnostics)).PropertyType,
+            Is.EqualTo(typeof(List<RoslynDiagnostic>)));
+        Assert.That(typeof(MultitaskerResults).GetConstructor(new[] { typeof(IEnumerable<RoslynDiagnostic>) }),
+            Is.Not.Null);
+    }
+
+    [Test]
+    public void CompilationDiagnosticIsRetainedWithoutConversion()
+    {
+        RoslynDiagnostic diagnostic = RoslynDiagnostic.Create(
+            new DiagnosticDescriptor("SAMREG001", "Compilation", "Invalid script", "Regression",
+                Microsoft.CodeAnalysis.DiagnosticSeverity.Error, true), Location.None);
+        var results = new MultitaskerResults(new[] { diagnostic });
+
+        Assert.That(results.Succedded, Is.False);
+        Assert.That(results.Diagnostics, Has.Count.EqualTo(1));
+        Assert.That(results.Diagnostics[0], Is.SameAs(diagnostic));
+    }
+
+    [Test]
+    public async Task InvalidScriptReturnsRoslynCompilationErrors()
+    {
+        MultitaskerResults results = await new Multitasker("this is not valid C#;").Run();
+
+        Assert.That(results.Succedded, Is.False);
+        Assert.That(results.Diagnostics.Any(d => d.Severity == Microsoft.CodeAnalysis.DiagnosticSeverity.Error), Is.True);
+    }
+}
@@ -0,0 +1,72 @@
+# Multitasker Roslyn Diagnostic collision — 2026-10-15
+
+## Status and scope
+
+PR [SAM_Multitasker#12](https://github.com/SAM-BIM/SAM_Multitasker/pull/12), focused correction into `sow/2026-Q4`, based on Multitasker `aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b`.
+Validated content SHA: `cfe9d116c1d9837e23ada308d535029eaf6de773`.
+Affected-project build, all four NUnit tests, and full BuildAlls_v5 pass locally. Initial PR-head GitHub Build and SPDX pass; final record-only head checks are reported in the PR description. No merge authorized.
+SAM#204 is unchanged and can proceed independently of this correction: the failure reproduces at its Q4 base, before its changes.
+
+## Proven cause and dependency boundary
+
+Within namespace `SAM.Core.Multitasker`, adding `SAM.Core.Diagnostic` changes resolution of the unqualified `Diagnostic` identifier from the imported Roslyn class to the enclosing SAM.Core class. `script.Compile()` still returns Roslyn diagnostics, producing CS0029. The same resolution affects the stored diagnostics and public result constructor/property, so both production files require explicit aliases.
+
+The first breaking SAM commit is `967a8639eb6f7f614ff4168d62ab3dfd979efbe4` (shared Diagnostics Phase 1, SAM#201, 2026-10-15 11:31 +02). Its immediate parent `a71435dd88d28c9b0da0bca43c21fbca5e1038b9` builds successfully with the identical Multitasker source. Multitasker was unchanged at `aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b`; the failing source originated in `4e7e01e61770b19f1647f387934c788e80b21c8c` (2024).
+
+Isolated `git archive` source builds, without switching the SAM checkout:
+
+| SAM SHA | Multitasker source | SAM.Core | Consumer | API/behavior probe |
+|---|---|---|---|---|
+| `0649e15ee9c1727af5834d9206017da9860917c5` | `aa126fa` | pass | pass | 4 assertions pass |
+| `a71435dd88d28c9b0da0bca43c21fbca5e1038b9` | `aa126fa` | pass | pass | 4 assertions pass |
+| `967a8639eb6f7f614ff4168d62ab3dfd979efbe4` | `aa126fa` | pass | CS0029 | not run |
+| `6b12e2a65817556693ba408674211610f4a20dda` (Q4 before #204) | `aa126fa` | pass | CS0029 | not run |
+| `967a8639eb6f7f614ff4168d62ab3dfd979efbe4` | `aa126fa` + alias fix | reused passing build | pass | 4 assertions pass |
+
+Only the SAM.Core reference varied in this boundary experiment; other SAM assembly references were held at the same local build. Each archive used the actual SAM.Core and consumer project/source, with scratch-only absolute HintPaths and `RunPostBuildEvent=Never`. The ordinary affected-project build independently reproduced the original CS0029 before the fix.
+
+## Last known good full configuration
+
+The latest preserved successful full run is the morning 2026-10-15 `BuildAlls_v5.bat nopause`, completed about 09:19:44 +02 in `00:09:32.0360117`: Restore/Clean/Rebuild across the 26 active repositories, Revit 2025/2026/2027, final native OCCT checks passed.
+Machine-local evidence: parent `.buildall-v5-validation/json-fix-2026-10-15/BuildAlls-full-build.log`, `BuildAlls-working-trees.log` and `BuildAlls-JSON-report.md`.
+
+That log did not record SHAs. The exact SHA configuration in [initial-and-morning-configurations.json](evidence/diagnostic-collision-2026-10-15/initial-and-morning-configurations.json) is **reconstructed from local HEAD reflogs**, not a contemporaneous SHA manifest: equal heads at 09:10:12 and 09:19:44 +02, no entries during 09:10–09:20 in any of the 26 repos, and the contemporaneous working-tree log reports all clean. Relevant heads: SAM `0649e15ee9c1727af5834d9206017da9860917c5`, Multitasker `aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b`.
+
+The same JSON records the clean investigation-start heads/branches. Multitasker's recorded feature branch was created from the clean Q4 head before edits; initial checkout was `sow/2026-Q4`. [full-build-configurations.json](evidence/diagnostic-collision-2026-10-15/full-build-configurations.json) records the current full-run heads, with Multitasker at the tested content SHA and SAM#204 at `4a8afbebb186ace81eb5d49aed32deb502120781`.
+
+## Changes and safeguards
+
+- `SAM_Multitasker/SAM.Core.Multitasker/Classes/Multitasker.cs`: distinct `RoslynDiagnostic` alias for compilation results.
+- `SAM_Multitasker/SAM.Core.Multitasker/Classes/MultitaskerResults.cs`: same alias for storage, constructor and public property. Historical CLR types remain `IEnumerable<Microsoft.CodeAnalysis.Diagnostic>` / `List<Microsoft.CodeAnalysis.Diagnostic>`.
+- Both touched production files receive required SPDX headers.
+- Existing `design/grasshopper-icons/tests/GhIconTest/GhIconTest.csproj`: reference the core project; new `MultitaskerDiagnosticsTests.cs` covers public types, object-preserving diagnostic transfer and invalid-script compilation errors.
+- This record and four compact JSON evidence files preserve the boundary and repository configurations.
+- No algorithm, component, shared SAM.Core type, workflow or PROJECT_PROGRESS change. No SAM#204 edits.
+
+## Reproduction and local validation
+
+Prerequisites: sibling SAM build first, .NET SDK, installed Rhino 8 for the existing NUnit host fixture. Builds emit existing System.Memory reference and nullable warnings; no new suppression added.
+
+From the Multitasker repository:
+
+```powershell
+dotnet build SAM_Multitasker/SAM.Core.Multitasker/SAM.Core.Multitasker.csproj -c Debug --no-restore -p:RunPostBuildEvent=Never
+$env:SAM_ICON_MANIFESTS = (Resolve-Path design/grasshopper-icons/manifest.json).Path
+$env:SAM_ICON_ASSEMBLY_DIR = (Resolve-Path build).Path
+dotnet test design/grasshopper-icons/tests/GhIconTest/GhIconTest.csproj -c Debug -p:RunPostBuildEvent=Never --logger 'trx;LogFileName=Multitasker-regression.trx'
+& ..\BuildAlls_v5.bat nopause
+```
+
+- Affected project: pass, 0 errors (2 warnings).
+- Existing NUnit project: **4 passed, 0 failed, 0 skipped** (three new regression tests plus existing icon test).
+- Isolated boundary: exact outcomes above, raw summary in [boundary-results.json](evidence/diagnostic-collision-2026-10-15/boundary-results.json).
+- Similar-collision audit: only other active Roslyn source is in SAM_Tas GenOpt test namespaces. It uses inferred diagnostic values and Roslyn DiagnosticSeverity without the affected SAM.Core namespace lookup; no equivalent collision found. No Tas changes.
+- Full BuildAlls_v5: **PASS**, exit 0, `00:07:41.6286121`, 2026-10-15 21:07:51–21:15:36 +02. All 26 active repositories Restore/Clean/Rebuild, Revit 2025/2026/2027 and final OCCT ABI/dependency/hash checks passed. CS0029 is absent; no new build errors. Existing warnings remain (package compatibility/duplicate references, assembly-version/architecture conflicts and XML documentation). This is build validation, not general installed-host engineering acceptance.
+- GitHub Build at record-only head `7f95bfb7d92006ae37324bf472717cc97929ba1a`: **PASS**, [run 38791612549](https://github.com/SAM-BIM/SAM_Multitasker/actions/runs/38791612549); SPDX also passed. Logs confirm `Cloning SAM-BIM/SAM @ sow/2026-Q4` and actual SAM.Core.Multitasker compilation with no CS0029. Final docs-only commit checks are tracked in the PR description.
+- Post-build status: all 26 source trees clean; only Multitasker head advanced from tested content by its record-only commit. SAM#204 remains clean at `4a8afbebb186ace81eb5d49aed32deb502120781`. [validation-results.json](evidence/diagnostic-collision-2026-10-15/validation-results.json) records full-run timing, test totals and SHA256 hashes of the retained machine-local logs/TRX.
+
+Machine-local scratch evidence is under `C:\Users\michal\.codex\visualizations\2026\10\15\01a140c3-07d7-7db2-83db-a3f98397ac92\multitasker-regression`: `investigate.py` archive harness, core/consumer/probe logs, affected-project log, NUnit TRX, and full-run log. These raw logs/harness are not committed; copy/provision them if needed on another machine. The committed tests, JSON matrix and exact SHAs/commands above preserve the critical outcomes. Original pre-fix log: adjacent `pr204-review/Multitasker-before-fix.log`.
+
+## Remaining work
+
+Verify final record-only head GitHub checks, then request owner review and merge only with approval. The tested source remains `cfe9d116c1d9837e23ada308d535029eaf6de773`; subsequent commits change records only. After merge, add the known-merge-SHA docs-only Q4 closeout under repository policy. Keep SAM#204 independent.
@@ -0,0 +1,38 @@
+[
+  {
+    "label": "morning-good",
+    "sam": "0649e15ee9c1727af5834d9206017da9860917c5",
+    "multitasker": "aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b",
+    "core_build_exit": 0,
+    "consumer_exit": 0,
+    "probe_exit": 0
+  },
+  {
+    "label": "parent-good",
+    "sam": "a71435dd88d28c9b0da0bca43c21fbca5e1038b9",
+    "multitasker": "aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b",
+    "core_build_exit": 0,
+    "consumer_exit": 0,
+    "probe_exit": 0
+  },
+  {
+    "label": "first-diagnostic",
+    "sam": "967a8639eb6f7f614ff4168d62ab3dfd979efbe4",
+    "multitasker": "aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b",
+    "core_build_exit": 0,
+    "consumer_exit": 1
+  },
+  {
+    "label": "q4-before-204",
+    "sam": "6b12e2a65817556693ba408674211610f4a20dda",
+    "multitasker": "aa126fa6eeb34cbffb72cbf5a5129aa17be1ec6b",
+    "core_build_exit": 0,
+    "consumer_exit": 1
+  },
+  {
+    "label": "first-diagnostic-fixed",
+    "sam": "967a8639eb6f7f614ff4168d62ab3dfd979efbe4",
+    "consumer_exit": 0,
+    "probe_exit": 0
+  }
+]
@@ -0,0 +1,158 @@
+[
+  {
+    "repository": "SAM",
+    "branch": "docs/gh-component-standards-q4",
+    "head": "4a8afbebb186ace81eb5d49aed32deb502120781",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Psychrometrics",
+    "branch": "sow/2026-Q4",
+    "head": "4db5756ed9957d625837014d6e8ce71e23df56b0",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Mollier",
+    "branch": "sow/2026-Q4",
+    "head": "7f61916adad9ad913904d18047ec6bfe835d1611",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Systems",
+    "branch": "sow/2026-Q4",
+    "head": "f0838ca3eba3e4b5f1cee008ba0831b6d7e95625",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Windows",
+    "branch": "sow/2026-Q4",
+    "head": "11bbecfa8aa854f4d9b2494c8bca737298982751",
+    "status": ""
+  },
+  {
+    "repository": "SAM_IFC",
+    "branch": "sow/2026-Q4",
+    "head": "77046bef504474619cf39afbbc70ee7975aad50c",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Acoustic",
+    "branch": "sow/2026-Q4",
+    "head": "baed72cb439f6c23fdd16725f497be67938dc54a",
+    "status": ""
+  },
+  {
+    "repository": "SAM_BHoM",
+    "branch": "sow/2026-Q4",
+    "head": "995caace61164bf281501613e8ec4f3008053f39",
+    "status": ""
+  },
+  {
+    "repository": "SAM_gbXML",
+    "branch": "sow/2026-Q4",
+    "head": "43b5d018ac7a8a14f332e8bcde9cb0d613bf1efb",
+    "status": ""
+  },
+  {
+    "repository": "SAM_GEM",
+    "branch": "sow/2026-Q4",
+    "head": "1bf41916fefa6dd5fe44a735c294619d3d8df8d9",
+    "status": ""
+  },
+  {
+    "repository": "SAM_LadybugTools",
+    "branch": "sow/2026-Q4",
+    "head": "0ffbaecf1097a33de2044ee919c963eaeb0a0da2",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Solver",
+    "branch": "sow/2026-Q4",
+    "head": "fd63b4670cd4baeb20a74312aacc17eb177ecc18",
+    "status": ""
+  },
+  {
+    "repository": "SAM_SolarCalculator",
+    "branch": "sow/2026-Q4",
+    "head": "277a3a4864f2bf900504a64a4830cb9438312d78",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Validation",
+    "branch": "sow/2026-Q4",
+    "head": "c9a7f193f46289f52eecdd4a7dc6179789f2c4e9",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Tas",
+    "branch": "sow/2026-Q4",
+    "head": "0589f0da7e2633478c26defdb237ceb0821ebdf9",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Tas_Grasshopper",
+    "branch": "sow/2026-Q4",
+    "head": "d827409a10e8911f9eb6b5e81d1cbb341c2fc0ce",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Excel",
+    "branch": "sow/2026-Q4",
+    "head": "6669977d07cc6488c0dd91fe0a48ccd2dc833627",
+    "status": ""
+  },
+  {
+    "repository": "SAM_SQLite",
+    "branch": "sow/2026-Q4",
+    "head": "ec2eb86d00cac6e4cadf52b429f9d293eeabbd5e",
+    "status": ""
+  },
+  {
+    "repository": "SAM_OpenStudio",
+    "branch": "feature/openstudio-diagnostics-phase4a-q4",
+    "head": "3746eed5a82281f22e94df76027a7f99cdbe68b8",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Origin",
+    "branch": "sow/2026-Q4",
+    "head": "74c19a1ebf3fc11a136cc9b055edf68b2b91a087",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Multitasker",
+    "branch": "codex/fix-roslyn-diagnostic-collision-q4",
+    "head": "cfe9d116c1d9837e23ada308d535029eaf6de773",
+    "status": ""
+  },
+  {
+    "repository": "SAM_OCCT",
+    "branch": "sow/2026-Q4",
+    "head": "aad68123373e0dfe5841ec9670ec1b004960c73f",
+    "status": ""
+  },
+  {
+    "repository": "SAM_UI",
+    "branch": "sow/2026-Q4",
+    "head": "ebe5e09b30b95e43e5d047b3aef2d8c5f01110e9",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Rhino_UI",
+    "branch": "sow/2026-Q4",
+    "head": "24fafda03cef5168abf1e43a1669a2fe42490f8d",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Revit",
+    "branch": "sow/2026-Q4",
+    "head": "431d34ef4bcff8f34e8caa32e893ebfc471cb678",
+    "status": ""
+  },
+  {
+    "repository": "SAM_Revit_UI",
+    "branch": "sow/2026-Q4",
+    "head": "06cf245af93dfd29521bbf925a4b7f3cf934af18",
+    "status": ""
+  }
+]