ci(windows): add DLL-not-found diagnostic steps

.github/workflows/build-test-windows.yml

@@ -111,6 +111,12 @@ jobs:
         working-directory: C:\vcpkg
         run: C:\vcpkg\vcpkg.exe integrate install
 
+      - name: Diagnostic — vcpkg installed tree
+        if: ${{ always() }}
+        shell: pwsh
+        continue-on-error: true
+        run: ./scripts/diagnostics/windows-vcpkg-tree.ps1 -Triplet "${{ matrix.vcpkg_triplet || 'x64-windows-meshlib' }}"
+
       - name: Restore CUDA Cache
         uses: actions/cache@v5
         id: cuda-cache
@@ -213,6 +219,13 @@ jobs:
           call "${{matrix.vc-path}}\Common7\Tools\VsDevCmd.bat" -arch=amd64 ${{ fromJSON('["", "-vcvars_ver=14.2"]')[matrix.cxx_compiler == 'msvc-2019'] }}
           call ./scripts/mrbind/generate_win.bat -B --trace MODE=none VS_MODE=${{matrix.config}}
 
+      - name: Diagnostic — output bin DLL inventory + MRMesh imports
+        if: ${{ always() }}
+        shell: pwsh
+        continue-on-error: true
+        working-directory: source\x64\${{ matrix.config }}
+        run: ${{ github.workspace }}\scripts\diagnostics\windows-bin-imports.ps1 -VcPath "${{ matrix.vc-path }}"
+
       - name: Run Start-and-Exit Tests
         timeout-minutes: 3
         working-directory: source\x64\${{ matrix.config }}

scripts/diagnostics/windows-bin-imports.ps1

@@ -0,0 +1,45 @@
+# Before launching MeshViewer.exe, dump the state the Windows loader will
+# actually see. Prints the DLLs present in the current directory, the
+# import tables of the key binaries (so we know which DLL names the loader
+# wants), and the PATH at launch. Lets DLL-not-found failures self-diagnose
+# from the CI log.
+#
+# Run from the directory containing MeshViewer.exe / MRMesh.dll / MRTest.exe.
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory = $true)][string]$VcPath
+)
+
+Write-Host "=== DLLs / EXEs in $(Get-Location) ==="
+Get-ChildItem . -File -Include *.dll,*.exe -Recurse -ErrorAction SilentlyContinue |
+    Select-Object Name, @{N='SizeKB';E={[int]($_.Length/1KB)}} |
+    Sort-Object Name | Format-Table -AutoSize
+
+# Locate dumpbin.exe via the VC path hint, then fall back to whatever is on
+# PATH (Visual Studio Integration step earlier populates MSBuild PATH, not
+# VC bin).
+$dumpbin = (Get-ChildItem "$VcPath\VC\Tools\MSVC\*\bin\Hostx64\x64\dumpbin.exe" -ErrorAction SilentlyContinue |
+            Select-Object -First 1).FullName
+if (-not $dumpbin) {
+    $dumpbin = (Get-Command dumpbin.exe -ErrorAction SilentlyContinue).Source
+}
+
+if ($dumpbin) {
+    Write-Host ""
+    Write-Host "Using dumpbin at: $dumpbin"
+    foreach ($target in 'MeshViewer.exe','MRMesh.dll','MRTest.exe') {
+        if (Test-Path $target) {
+            Write-Host ""
+            Write-Host "=== Import table of $target (dumpbin /dependents) ==="
+            & $dumpbin /dependents $target |
+                Where-Object { $_ -match '\.dll$' } |
+                ForEach-Object { "  " + $_.Trim() }
+        }
+    }
+} else {
+    Write-Warning "dumpbin.exe not found; skipping import-table dump"
+}
+
+Write-Host ""
+Write-Host "=== PATH at diagnostic step ==="
+$env:PATH -split ';' | ForEach-Object { "  $_" }

scripts/diagnostics/windows-vcpkg-tree.ps1

@@ -0,0 +1,22 @@
+# Inventory the vcpkg installed tree so DLL-not-found failures later in the
+# build can be traced back to whether the DLL was (a) never installed,
+# (b) installed under an unexpected name, or (c) installed fine but not
+# copied to the build output.
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory = $true)][string]$Triplet
+)
+
+Write-Host "=== Triplet: $Triplet ==="
+foreach ($sub in 'bin', 'debug\bin', 'lib', 'debug\lib') {
+    $dir = "C:\vcpkg\installed\$Triplet\$sub"
+    Write-Host ""
+    Write-Host "--- $dir ---"
+    if (Test-Path $dir) {
+        Get-ChildItem $dir -File -ErrorAction SilentlyContinue |
+            Select-Object Name, @{N='SizeKB';E={[int]($_.Length/1KB)}} |
+            Sort-Object Name | Format-Table -AutoSize
+    } else {
+        Write-Host "(directory not present)"
+    }
+}