Merge branch 'nano-server'

This patch adds a GitHub workflow (to be triggered manually) to allow
for conveniently verifying that Git and Scalar still work as intended in
Windows Nano Server (a relatively small container base image that is
frequently used where a "small Windows" is needed, e.g. in automation
;-))

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

.github/workflows/nano-server.yml

@@ -0,0 +1,76 @@
+name: Windows Nano Server tests
+
+on:
+  workflow_dispatch:
+
+env:
+  DEVELOPER: 1
+
+jobs:
+  test-nano-server:
+    runs-on: windows-2022
+    env:
+      WINDBG_DIR: "C:/Program Files (x86)/Windows Kits/10/Debuggers/x64"
+      IMAGE: mcr.microsoft.com/powershell:nanoserver-ltsc2022
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: git-for-windows/setup-git-for-windows-sdk@v1
+      - name: build Git
+        shell: bash
+        run: make -j15
+      - name: pull nanoserver image
+        shell: bash
+        run: docker pull $IMAGE
+      - name: run nano-server test
+        shell: bash
+        run: |
+          docker run \
+            --user "ContainerAdministrator" \
+            -v "$WINDBG_DIR:C:/dbg" \
+            -v "$(cygpath -aw /mingw64/bin):C:/mingw64-bin" \
+            -v "$(cygpath -aw .):C:/test" \
+            $IMAGE pwsh.exe -Command '
+              # Extend the PATH to include the `.dll` files in /mingw64/bin/
+              $env:PATH += ";C:\mingw64-bin"
+
+              # For each executable to test pick some no-operation set of
+              # flags/subcommands or something that should quickly result in an
+              # error with known exit code that is not a negative 32-bit
+              # number, and set the expected return code appropriately.
+              #
+              # Only test executables that could be expected to run in a UI
+              # less environment.
+              #
+              # ( Executable path, arguments, expected return code )
+              # also note space is required before close parenthesis (a
+              # powershell quirk when defining nested arrays like this)
+
+              $executables_to_test = @(
+                  ("C:\test\git.exe", "", 1 ),
+                  ("C:\test\scalar.exe", "version", 0 )
+              )
+
+              foreach ($executable in $executables_to_test)
+              {
+                  Write-Output "Now testing $($executable[0])"
+                  &$executable[0] $executable[1]
+                  if ($LASTEXITCODE -ne $executable[2]) {
+                      # if we failed, run the debugger to find out what function
+                      # or DLL could not be found and then exit the script with
+                      # failure The missing DLL or EXE will be referenced near
+                      # the end of the output
+
+                      # Set a flag to have the debugger show loader stub
+                      # diagnostics. This requires running as administrator,
+                      # otherwise the flag will be ignored.
+                      C:\dbg\gflags -i $executable[0] +SLS
+
+                      C:\dbg\cdb.exe -c "g" -c "q" $executable[0] $executable[1]
+
+                      exit 1
+                  }
+              }
+
+              exit 0
+            '