Ensure that all post-build checks have skip policies.

Also audit for:
* Consistently following the 'IDE error format' pointing to portfile.cmake.
* Consistently referring to the correct skip policy in the error message where applicable.
* Printing paths and other information relative to ${CURRENT_PACKAGES_DIR} or similar as appropriate.
* Debug before release.
* Don't duplicate messages when a problem happens for both debug and release.

Drive by bugfix:

    if (!build_info.policies.is_enabled(BuildPolicy::ONLY_RELEASE_CRT))
    {
        error_count += check_crt_linkage_of_libs(
            build_info, false, debug_libs, debug_lib_info.value_or_exit(VCPKG_LINE_INFO), msg_sink);
    }

was wrong; ONLY_RELEASE_CRT should mean 'these should all be release', not 'we aren't even going to look at debug'.

It is fixed to:

    error_count += check_crt_linkage_of_libs(build_info.crt_linkage,
                                              build_info.policies.is_enabled(BuildPolicy::ONLY_RELEASE_CRT),
                                              debug_libs,
                                              debug_lib_info.value_or_exit(VCPKG_LINE_INFO),
                                              msg_sink);

here.

Drive-by bugfix:
EMPTY_INCLUDE_FOLDER should not block CMAKE_HELPER_PORT from checking that the include folder is, in fact, empty.

Drive-by bugfix:
        if (!violations.empty())
        {
            msg_sink.println_warning(msgPortBugRestrictedHeaderPaths);
            print_paths(msg_sink, violations);
            msg_sink.println(msgPortBugRestrictedHeaderPaths);     // <-- duplicate!
            return LintStatus::PROBLEM_DETECTED;
        }

Drive-by bugfix:
There were duplicate checks for the lib/cmake and debug/lib/cmake directories which even printed the same message; these have been merged.

Drive-by bugfix:
The existing copyright check emitted nonsense output that included full absolute paths like:
warning: The software license must be available at ${CURRENT_PACKAGES_DIR}/share/cmdline/copyright. vcpkg_install_copyright(FILE_LIST "${SOURCE_PATH}/D:/b/cmdline//LICENSE")
since at least microsoft#1116
That check has been basically rewritten to use vcpkg_install_copyright if there's only one src directory, and otherwise give up and print them all

Drive-by bugfix:
Several of the outdated CRTs didn't have the debug versions listed. Also, P was duplicated and there was no R for VC6.

azure-pipelines/e2e-assets/test-dll-port-template/portfile.cmake

@@ -1,14 +1,69 @@
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/bin")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/lib")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/bin")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/lib")
 file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/include")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share")
-file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
-file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/bin")
-file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib")
-file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/bin")
-file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
 file(COPY "${CMAKE_CURRENT_LIST_DIR}/test.h" DESTINATION "${CURRENT_PACKAGES_DIR}/include")
+
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
 file(TOUCH "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+
+if(release-only IN_LIST FEATURES AND NOT bad-release-only IN_LIST FEATURES)
+    set(VCPKG_BUILD_TYPE release)
+endif()
+
+if(NOT install-no-lib-release IN_LIST FEATURES AND NOT debug-only IN_LIST FEATURES)
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/lib")
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
+endif()
+
+if(NOT install-no-lib-debug IN_LIST FEATURES AND NOT release-only IN_LIST FEATURES)
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/lib")
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib")
+endif()
+
+if(install-to-lib IN_LIST FEATURES)
+    if(NOT debug-only IN_LIST FEATURES)
+        file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
+    endif()
+    if(NOT release-only IN_LIST FEATURES)
+        file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib")
+    endif()
+else()
+    if(NOT debug-only IN_LIST FEATURES)
+        file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/bin")
+        file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/bin")
+    endif()
+    if(NOT release-only IN_LIST FEATURES)
+        file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/bin")
+        file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/bin")
+    endif()
+endif()
+
+if(extra-debug IN_LIST FEATURES)
+    file(INSTALL "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib" RENAME "test_dll2.lib")
+    file(INSTALL "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/bin" RENAME "test_dll2.dll")
+endif()
+
+if(extra-release IN_LIST FEATURES)
+    file(INSTALL "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib" RENAME "test_dll2.lib")
+    file(INSTALL "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/bin" RENAME "test_dll2.dll")
+endif()
+
+if(policy-skip-architecture-check IN_LIST FEATURES)
+    set(VCPKG_POLICY_SKIP_ARCHITECTURE_CHECK enabled)
+endif()
+if(policy-skip-appcontainer-check IN_LIST FEATURES)
+    set(VCPKG_POLICY_SKIP_APPCONTAINER_CHECK enabled)
+endif()
+if(policy-allow-dlls-in-lib IN_LIST FEATURES)
+    set(VCPKG_POLICY_ALLOW_DLLS_IN_LIB enabled)
+endif()
+if(policy-allow-kernel32-from-xbox IN_LIST FEATURES)
+    set(VCPKG_POLICY_ALLOW_KERNEL32_FROM_XBOX enabled)
+endif()
+if(policy-dlls-in-static-library IN_LIST FEATURES)
+    set(VCPKG_POLICY_DLLS_IN_STATIC_LIBRARY enabled)
+endif()
+if(policy-mismatched-number-of-binaries IN_LIST FEATURES)
+    set(VCPKG_POLICY_MISMATCHED_NUMBER_OF_BINARIES enabled)
+endif()
+if(policy-dlls-without-libs IN_LIST FEATURES)
+    set(VCPKG_POLICY_DLLS_WITHOUT_LIBS enabled)
+endif()

azure-pipelines/e2e-assets/test-dll-port-template/vcpkg.json

@@ -1,4 +1,59 @@
 {
   "name": "test-dll",
-  "version": "1.0.0"
+  "version": "1.0.0",
+  "features": {
+    "bad-release-only": {
+      "description": "Install only the release versions, but don't set the build type",
+      "dependencies": [
+        {
+          "name": "test-dll",
+          "features": [
+            "release-only"
+          ]
+        }
+      ]
+    },
+    "debug-only": {
+      "description": "Install only the debug versions"
+    },
+    "extra-debug": {
+      "description": "Install an extra debug DLL"
+    },
+    "extra-release": {
+      "description": "Install an extra release DLL"
+    },
+    "install-to-lib": {
+      "description": "Incorrectly install the DLL to lib instead of bin"
+    },
+    "install-no-lib-debug": {
+      "description": "Incorrectly install no import lib for debug only"
+    },
+    "install-no-lib-release": {
+      "description": "Incorrectly install no import lib for release only"
+    },
+    "policy-allow-dlls-in-lib": {
+      "description": "Turn on VCPKG_POLICY_ALLOW_DLLS_IN_LIB"
+    },
+    "policy-allow-kernel32-from-xbox": {
+      "description": "Turn on VCPKG_POLICY_ALLOW_KERNEL32_FROM_XBOX"
+    },
+    "policy-dlls-in-static-library": {
+      "description": "Turn on VCPKG_POLICY_DLLS_IN_STATIC_LIBRARY"
+    },
+    "policy-skip-appcontainer-check": {
+      "description": "Turn on VCPKG_POLICY_SKIP_APPCONTAINER_CHECK"
+    },
+    "policy-skip-architecture-check": {
+      "description": "Turn on VCPKG_POLICY_SKIP_ARCHITECTURE_CHECK"
+    },
+    "policy-mismatched-number-of-binaries": {
+      "description": "Turn on VCPKG_POLICY_MISMATCHED_NUMBER_OF_BINARIES"
+    },
+    "policy-dlls-without-libs": {
+      "description": "Turn on VCPKG_POLICY_DLLS_WITHOUT_LIBS"
+    },
+    "release-only": {
+      "description": "Install only the release versions"
+    }
+  }
 }

azure-pipelines/e2e-assets/test-exe-port-template/build.cmd

@@ -0,0 +1,4 @@
+mkdir "%~dp0debug"
+mkdir "%~dp0release"
+cl /MDd "%~dp0test.c" /Fo"%~dp0debug\test.obj" /Fe"%~dp0debug\test_exe.exe"
+cl /MD "%~dp0test.c" /Fo"%~dp0release\test.obj" /Fe"%~dp0release\test_exe.exe"

azure-pipelines/e2e-assets/test-exe-port-template/portfile.cmake

@@ -0,0 +1,17 @@
+set(VCPKG_POLICY_EMPTY_INCLUDE_FOLDER enabled)
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
+file(TOUCH "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+
+if(release-only IN_LIST FEATURES)
+    set(VCPKG_BUILD_TYPE release)
+else()
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/bin")
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_exe.exe" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/bin")
+endif()
+
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/bin")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_exe.exe" DESTINATION "${CURRENT_PACKAGES_DIR}/bin")
+
+if(policy-allow-exes-in-bin IN_LIST FEATURES)
+    set(VCPKG_POLICY_ALLOW_EXES_IN_BIN enabled)
+endif()

azure-pipelines/e2e-assets/test-exe-port-template/test.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main()
+{
+    puts("hello world");
+    return 0;
+}

azure-pipelines/e2e-assets/test-exe-port-template/vcpkg.json

@@ -0,0 +1,12 @@
+{
+  "name": "test-exe",
+  "version": "1.0.0",
+  "features": {
+    "release-only": {
+      "description": "Only install release binaries"
+    },
+    "policy-allow-exes-in-bin": {
+      "description": "Turn on VCPKG_POLICY_ALLOW_EXES_IN_BIN"
+    }
+  }
+}

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt-release-only/build.cmd

@@ -0,0 +1,6 @@
+mkdir "%~dp0debug"
+mkdir "%~dp0release"
+cl /c /DNDEBUG /MD "%~dp0test.c" /Fo"%~dp0debug\test.obj"
+lib "%~dp0debug\test.obj" /OUT:"%~dp0debug\test_lib.lib"
+cl /c /DNDEBUG /MD "%~dp0test.c" /Fo"%~dp0release\test.obj"
+lib "%~dp0release\test.obj" /OUT:"%~dp0release\test_lib.lib"

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt-release-only/portfile.cmake

@@ -0,0 +1,16 @@
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/lib")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/lib")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/include")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_lib.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_lib.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/test.h" DESTINATION "${CURRENT_PACKAGES_DIR}/include")
+file(TOUCH "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+if (policy-skip-crt-linkage-check IN_LIST FEATURES)
+	set(VCPKG_POLICY_SKIP_CRT_LINKAGE_CHECK enabled)
+endif()
+if (policy-only-release-crt IN_LIST FEATURES)
+	set(VCPKG_POLICY_ONLY_RELEASE_CRT enabled)
+endif()

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt-release-only/test.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int __cdecl test_fn() {
+    puts("You called the static lib function!");
+    return 42;
+}

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt-release-only/test.h

@@ -0,0 +1 @@
+int __cdecl test_fn();

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt-release-only/vcpkg.json

@@ -0,0 +1,12 @@
+{
+  "name": "test-lib",
+  "version": "1.0.0",
+  "features": {
+    "policy-skip-crt-linkage-check": {
+      "description": "Turn on VCPKG_POLICY_SKIP_CRT_LINKAGE_CHECK"
+    },
+    "policy-only-release-crt": {
+      "description": "Turn on VCPKG_POLICY_ONLY_RELEASE_CRT"
+    }
+  }
+}

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt/portfile.cmake

@@ -10,3 +10,6 @@ file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_lib.lib" DESTINATION "${CURREN
 file(COPY "${CMAKE_CURRENT_LIST_DIR}/both/both_lib.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
 file(COPY "${CMAKE_CURRENT_LIST_DIR}/test.h" DESTINATION "${CURRENT_PACKAGES_DIR}/include")
 file(TOUCH "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+if (policy-skip-crt-linkage-check IN_LIST FEATURES)
+	set(VCPKG_POLICY_SKIP_CRT_LINKAGE_CHECK enabled)
+endif()

azure-pipelines/e2e-assets/test-lib-port-template-dynamic-crt/vcpkg.json

@@ -1,4 +1,9 @@
 {
   "name": "test-lib",
-  "version": "1.0.0"
+  "version": "1.0.0",
+  "features": {
+    "policy-skip-crt-linkage-check": {
+      "description": "Turn on VCPKG_POLICY_SKIP_CRT_LINKAGE_CHECK"
+    }
+  }
 }

azure-pipelines/e2e-ports/vcpkg-internal-dll-with-no-exports/portfile.cmake

@@ -10,3 +10,6 @@ file(REMOVE_RECURSE
     "${CURRENT_PACKAGES_DIR}/debug/lib"
     "${CURRENT_PACKAGES_DIR}/lib")
 file(TOUCH "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+if(policy IN_LIST FEATURES)
+    set(VCPKG_POLICY_DLLS_WITHOUT_EXPORTS enabled)
+endif()

azure-pipelines/e2e-ports/vcpkg-internal-dll-with-no-exports/vcpkg.json

@@ -6,5 +6,10 @@
       "name": "vcpkg-cmake",
       "host": true
     }
-  ]
+  ],
+  "features": {
+    "policy": {
+      "description": "Turn on VCPKG_POLICY_DLLS_WITHOUT_EXPORTS"
+    }
+  }
 }

azure-pipelines/e2e-ports/vcpkg-msvc-2013/build.cmd

@@ -0,0 +1,5 @@
+:: This must be run from a Visual Studio 2013 command prompt
+mkdir "%~dp0debug"
+mkdir "%~dp0release"
+cl /MDd "%~dp0test.c" "%~dp0test.def" /Fo"%~dp0debug\test.obj" /Fe"%~dp0debug\test_dll.dll" /link /DLL
+cl /MD "%~dp0test.c" "%~dp0test.def" /Fo"%~dp0release\test.obj" /Fe"%~dp0release\test_dll.dll" /link /DLL

azure-pipelines/e2e-ports/vcpkg-msvc-2013/portfile.cmake

@@ -0,0 +1,23 @@
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
+file(WRITE "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright" "MIT License.")
+
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/include/vcpkg-msvc-2013")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/test.h" DESTINATION "${CURRENT_PACKAGES_DIR}/include/vcpkg-msvc-2013")
+
+if(release-only IN_LIST FEATURES)
+    set(VCPKG_BUILD_TYPE "release")
+else()
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/bin")
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/debug/lib")
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/bin")
+    file(COPY "${CMAKE_CURRENT_LIST_DIR}/debug/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/debug/lib")
+endif()
+
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/bin")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/lib")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.dll" DESTINATION "${CURRENT_PACKAGES_DIR}/bin")
+file(COPY "${CMAKE_CURRENT_LIST_DIR}/release/test_dll.lib" DESTINATION "${CURRENT_PACKAGES_DIR}/lib")
+
+if(policy IN_LIST FEATURES)
+    set(VCPKG_POLICY_ALLOW_OBSOLETE_MSVCRT enabled)
+endif()

azure-pipelines/e2e-ports/vcpkg-msvc-2013/test.c

@@ -0,0 +1,17 @@
+#include <windows.h>
+#include <stdio.h>
+
+BOOLEAN WINAPI DllMain(HINSTANCE hDllHandle, DWORD nReason, LPVOID Reserved)
+{
+    (void)Reserved;
+    if (nReason == DLL_PROCESS_ATTACH) {
+        DisableThreadLibraryCalls( hDllHandle );
+    }
+
+    return TRUE;
+}
+
+int __cdecl export_me() {
+    puts("You called the exported function!");
+    return 42;
+}

azure-pipelines/e2e-ports/vcpkg-msvc-2013/test.def

@@ -0,0 +1,4 @@
+LIBRARY test_dll
+
+EXPORTS
+export_me

azure-pipelines/e2e-ports/vcpkg-msvc-2013/test.h

@@ -0,0 +1 @@
+    // empty test header

azure-pipelines/e2e-ports/vcpkg-msvc-2013/vcpkg.json

@@ -0,0 +1,12 @@
+{
+  "name": "vcpkg-msvc-2013",
+  "version": "1",
+  "features": {
+    "policy": {
+      "description": "Set VCPKG_POLICY_ALLOW_OBSOLETE_MSVCRT"
+    },
+    "release-only": {
+      "description": "Only install the release DLL"
+    }
+  }
+}

azure-pipelines/e2e-ports/vcpkg-policy-copyright/portfile.cmake

@@ -0,0 +1,26 @@
+set(VCPKG_POLICY_EMPTY_INCLUDE_FOLDER enabled)
+
+if(copyright-directory IN_LIST FEATURES)
+    file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright")
+    file(WRITE "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright/LICENSE.txt" "this is some license text")
+    file(WRITE "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright/COPYING" "this is some different license text")
+else()
+    # Intentionally do not create "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright"
+endif()
+
+if(source IN_LIST FEATURES)
+    set(SOURCE_PATH "${CURRENT_BUILDTREES_DIR}/src/v1.16.3-6f5be3c3eb.clean")
+    file(MAKE_DIRECTORY "${SOURCE_PATH}")
+    file(WRITE "${SOURCE_PATH}/LICENSE.txt" "this is some license text")
+endif()
+
+if(source2 IN_LIST FEATURES)
+    set(SOURCE_PATH "${CURRENT_BUILDTREES_DIR}/src/v1.3.1-2e5db616bf.clean")
+    file(MAKE_DIRECTORY "${SOURCE_PATH}")
+    file(WRITE "${SOURCE_PATH}/LICENSE.txt" "this is some license text")
+    file(WRITE "${SOURCE_PATH}/COPYING" "this is some different license text")
+endif()
+
+if (policy IN_LIST FEATURES)
+    set(VCPKG_POLICY_SKIP_COPYRIGHT_CHECK enabled)
+endif()

azure-pipelines/e2e-ports/vcpkg-policy-copyright/vcpkg.json

@@ -0,0 +1,18 @@
+{
+  "name": "vcpkg-policy-copyright",
+  "version": "1",
+  "features": {
+    "policy": {
+      "description": "enable VCPKG_POLICY_SKIP_COPYRIGHT_CHECK"
+    },
+    "source": {
+      "description": "Create a source so that ${SOURCE_PATH} can be assumed to work"
+    },
+    "source2": {
+      "description": "Create another source so that ${SOURCE_PATH} can't be assumed to work"
+    },
+    "copyright-directory": {
+      "description": "create ${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright as a directory"
+    }
+  }
+}

azure-pipelines/e2e-ports/vcpkg-policy-empty-folders/portfile.cmake

@@ -0,0 +1,8 @@
+set(VCPKG_POLICY_EMPTY_INCLUDE_FOLDER enabled)
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/share/${PORT}")
+file(WRITE "${CURRENT_PACKAGES_DIR}/share/${PORT}/copyright" "this is some license text")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/empty-directory")
+file(MAKE_DIRECTORY "${CURRENT_PACKAGES_DIR}/root/empty-inner-directory")
+if (policy IN_LIST FEATURES)
+    set(VCPKG_POLICY_ALLOW_EMPTY_FOLDERS enabled)
+endif()