Test --skip-failures and fix "static" cascade

azure-pipelines/e2e-assets/ci-skipped-ports/baseline.fail.txt

@@ -0,0 +1,13 @@
+# fail means skip with --skip-failures
+always-skip:arm64-osx=fail
+always-skip:x64-linux=fail
+always-skip:x64-osx=fail
+always-skip:x64-windows=fail
+always-skip:x86-windows=fail
+
+# fail means skip here, but cached artifacts exists
+maybe-skip:arm64-osx=fail
+maybe-skip:x64-linux=fail
+maybe-skip:x64-osx=fail
+maybe-skip:x64-windows=fail
+maybe-skip:x86-windows=fail

azure-pipelines/e2e-assets/ci-skipped-ports/baseline.skip.txt

@@ -0,0 +1,13 @@
+# actual test
+always-skip:arm64-osx=skip
+always-skip:x64-linux=skip
+always-skip:x64-osx=skip
+always-skip:x64-windows=skip
+always-skip:x86-windows=skip
+
+# don't build cached artifact
+maybe-transitive-cascade:arm64-osx=skip
+maybe-transitive-cascade:x64-linux=skip
+maybe-transitive-cascade:x64-osx=skip
+maybe-transitive-cascade:x64-windows=skip
+maybe-transitive-cascade:x86-windows=skip

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-direct-cascade/portfile.cmake

@@ -0,0 +1 @@
+set(VCPKG_POLICY_EMPTY_PACKAGE enabled)

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-direct-cascade/vcpkg.json

@@ -0,0 +1,7 @@
+{
+  "name": "maybe-direct-cascade",
+  "version": "1.0.0",
+  "dependencies": [
+    "maybe-skip"
+  ]
+}

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-skip/portfile.cmake

@@ -0,0 +1 @@
+set(VCPKG_POLICY_EMPTY_PACKAGE enabled)

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-skip/vcpkg.json

@@ -0,0 +1,4 @@
+{
+  "name": "maybe-skip",
+  "version": "1.0.0"
+}

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-transitive-cascade/portfile.cmake

@@ -0,0 +1,4 @@
+set(VCPKG_POLICY_EMPTY_PACKAGE enabled)
+if(NOT EXISTS "${CURRENT_INSTALLED_DIR}/share/maybe-skip")
+    message(FATAL_ERROR "Installation order violation")
+endif()

azure-pipelines/e2e-assets/ci-skipped-ports/maybe-transitive-cascade/vcpkg.json

@@ -0,0 +1,7 @@
+{
+  "name": "maybe-transitive-cascade",
+  "version": "1.0.0",
+  "dependencies": [
+    "maybe-direct-cascade"
+  ]
+}

azure-pipelines/end-to-end-tests-dir/ci.ps1

@@ -95,26 +95,51 @@ SUMMARY FOR $Triplet
 
 # test that skipped ports aren't "put back" by downstream dependencies that aren't skipped
 Refresh-TestRoot
-$Output = Run-VcpkgAndCaptureOutput ci @commonArgs --x-builtin-ports-root="$PSScriptRoot/../e2e-assets/ci-skipped-ports" --binarysource=clear --ci-baseline="$PSScriptRoot/../e2e-assets/ci-skipped-ports/baseline.txt"
+$Output = Run-VcpkgAndCaptureOutput ci @commonArgs --x-builtin-ports-root="$PSScriptRoot/../e2e-assets/ci-skipped-ports" --binarysource="clear;files,$ArchiveRoot,readwrite" --ci-baseline="$PSScriptRoot/../e2e-assets/ci-skipped-ports/baseline.skip.txt"
 Throw-IfFailed
 if (-not ($Output -match 'always-built:[^:]+:      \*:' -and $Output -match 'Building always-built:[^@]+@1\.0\.0\.\.\.')) {
     throw 'did not attempt to build always-built'
 }
 if (-not ($Output -match 'always-skip:[^:]+: skip\n')) {
-    throw 'tried to build skipped'
+    throw 'did not identify always-skip as skipped'
+}
+if (-not ($Output -match 'always-cascade:[^:]+: cascade\n')) {
+    throw 'did not identify always-cascade as cascaded'
 }
-# This should be statically determinable but at the moment we do not
-# if (-not ($Output -match 'always-cascade:[^:]+: cascade\n')) {
-#     throw 'tried to build cascaded'
-# }
 Throw-IfNonContains -Actual $Output -Expected @"
 SUMMARY FOR $Triplet
-  SUCCEEDED: 1
+  SUCCEEDED: 3
   CASCADED_DUE_TO_MISSING_DEPENDENCIES: 1
-  EXCLUDED: 1
+  EXCLUDED: 2
 "@
+# prerequisite for next test
+if (-not ($Output -match 'maybe-transitive-cascade:[^:]+: skip\n')) {
+    throw 'did not identify maybe-transitive-cascade as skip'
+}
+# test with --skip-failures and cached artifacts
+Remove-Item -Recurse -Force $installRoot -ErrorAction SilentlyContinue
+New-Item -ItemType Directory -Path $installRoot -Force | Out-Null
+$Output = Run-VcpkgAndCaptureOutput ci --skip-failures @commonArgs --x-builtin-ports-root="$PSScriptRoot/../e2e-assets/ci-skipped-ports" --binarysource="clear;files,$ArchiveRoot" --ci-baseline="$PSScriptRoot/../e2e-assets/ci-skipped-ports/baseline.fail.txt"
+Throw-IfFailed
+if (-not ($Output -match 'always-built:[^:]+: cached:') -or $Output -match 'Building always-built:[^@]+@1\.0\.0\.\.\.') {
+    throw 'did not reuse the cached artifact for always-built'
+}
+if (-not ($Output -match 'always-skip:[^:]+: skip\n')) {
+    throw 'did not identify always-skip as skipped'
+}
+if (-not ($Output -match 'always-cascade:[^:]+: cascade\n')) {
+    throw 'did not identify always-cascade as cascaded'
+}
+if (-not ($Output -match 'maybe-skip:[^:]+: skip\n')) {
+    throw 'did not identify maybe-skip as skipped'
+}
+# not cached and transitive dependency on maybe-skip which is excluded
+if (-not ($Output -match 'maybe-transitive-cascade:[^:]+: cascade\n')) {
+    throw 'did not identify maybe-transitive-cascade as cascaded'
+}
 
 # test that features included only by skipped ports are not included
+Refresh-TestRoot
 $xunitFile = Join-Path $TestingRoot 'xunit.xml'
 Refresh-TestRoot
 Remove-Problem-Matchers

src/vcpkg/commands.ci.cpp

@@ -83,6 +83,18 @@ namespace
         return supports_expression.evaluate(var_provider.get_dep_info_vars(spec).value_or_exit(VCPKG_LINE_INFO));
     }
 
+    bool cascade_for_triplet(const std::vector<InstallPlanAction>& install_actions,
+                             const SortedVector<std::string>* triplet_exclusions)
+    {
+        if (!triplet_exclusions) return false;
+
+        return std::any_of(
+            install_actions.begin(), install_actions.end(), [triplet_exclusions](const InstallPlanAction& action) {
+                return action.source_control_file_and_location.has_value() &&
+                       triplet_exclusions->contains(action.source_control_file_and_location.get()->to_name());
+            });
+    }
+
     ActionPlan compute_full_plan(const VcpkgPaths& paths,
                                  const PortFileProvider& provider,
                                  const CMakeVars::CMakeVarProvider& var_provider,
@@ -332,9 +344,9 @@ namespace
             }
 
             PackagesDirAssigner this_packages_dir_not_used{""};
-            if (!create_feature_install_plan(
-                     provider, var_provider, {&full_package_spec, 1}, {}, this_packages_dir_not_used, serialize_options)
-                     .unsupported_features.empty())
+            const ActionPlan action_plan = create_feature_install_plan(
+                provider, var_provider, {&full_package_spec, 1}, {}, this_packages_dir_not_used, serialize_options);
+            if (!action_plan.unsupported_features.empty())
             {
                 result.excluded.insert_or_assign(
                     std::move(full_package_spec.package_spec),
@@ -344,6 +356,12 @@ namespace
                 continue;
             }
 
+            if (cascade_for_triplet(action_plan.install_actions, target_triplet_exclusions))
+            {
+                result.excluded.insert_or_assign(std::move(full_package_spec.package_spec), ExcludeReason::Cascade);
+                continue;
+            }
+
             result.requested.emplace_back(std::move(full_package_spec));
         }