Add default installer precedence if not defined by user

doc/ReleaseNotes.md

@@ -47,6 +47,14 @@ The WinGet MCP server's existing tools have been extended with new parameters to
 
 The PowerShell module now automatically uses `GH_TOKEN` or `GITHUB_TOKEN` environment variables to authenticate GitHub API requests. This significantly increases the GitHub API rate limit, preventing failures in CI/CD pipelines. Use `-Verbose` to see which token is being used.
 
+### Default priority of installer types
+
+Installer type selection no longer depends on the order defined on the manifest. Instead, preference is given in this order:
+- MSIX
+- MSI / Wix / Burn
+- Nullsoft / Inno / EXE
+- Portable
+
 ## Bug Fixes
 
 * Fixed the `useLatest` property in the DSC v3 `Microsoft.WinGet/Package` resource schema to emit a boolean default (`false`) instead of the incorrect string `"false"`.

src/AppInstallerCLITests/ManifestComparator.cpp

@@ -199,8 +199,8 @@ TEST_CASE("ManifestComparator_InstalledTypeFilter", "[manifest_comparator]")
         ManifestComparator mc(GetManifestComparatorOptions(ManifestComparatorTestContext{}, {}));
         auto [result, inapplicabilities] = mc.GetPreferredInstaller(manifest);
 
-        // Only because it is first
-        RequireInstaller(result, msi);
+        // Msix is preferred over Msi by the default installer type precedence order
+        RequireInstaller(result, msix);
         REQUIRE(inapplicabilities.size() == 0);
     }
     SECTION("MSI Installed")
@@ -238,7 +238,7 @@ TEST_CASE("ManifestComparator_InstalledTypeCompare", "[manifest_comparator]")
         ManifestComparator mc(GetManifestComparatorOptions(ManifestComparatorTestContext{}, {}));
         auto [result, inapplicabilities] = mc.GetPreferredInstaller(manifest);
 
-        // Only because it is first
+        // Burn is preferred over Exe by the default installer type precedence order
         RequireInstaller(result, burn);
         REQUIRE(inapplicabilities.size() == 0);
     }
@@ -855,6 +855,31 @@ TEST_CASE("ManifestComparator_InstallerType", "[manifest_comparator]")
         REQUIRE(!result);
         RequireInapplicabilities(inapplicabilities, { InapplicabilityFlags::InstallerType, InapplicabilityFlags::InstallerType, InapplicabilityFlags::InstallerType });
     }
+    SECTION("No user preference - default order applies")
+    {
+        // No TestUserSettings means no user-configured preferences; the default order should be used.
+        // Default order: MSStore > Msix > Msi > Wix > Burn > Nullsoft > Inno > Exe > Portable
+        // Manifest has Msi, Exe, Msix — Msix should win.
+        ManifestComparator mc(GetManifestComparatorOptions(ManifestComparatorTestContext{}, {}));
+        auto [result, inapplicabilities] = mc.GetPreferredInstaller(manifest);
+
+        RequireInstaller(result, msix);
+        REQUIRE(inapplicabilities.size() == 0);
+    }
+    SECTION("No user preference - type not in default list does not win over default-ordered types")
+    {
+        // Zip is not in the default preference list; it should not be preferred over Msix/Msi/Exe.
+        Manifest localManifest;
+        ManifestInstaller zip = AddInstaller(localManifest, Architecture::Neutral, InstallerTypeEnum::Zip, ScopeEnum::User);
+        ManifestInstaller localExe = AddInstaller(localManifest, Architecture::Neutral, InstallerTypeEnum::Exe, ScopeEnum::User);
+
+        ManifestComparator mc(GetManifestComparatorOptions(ManifestComparatorTestContext{}, {}));
+        auto [result, inapplicabilities] = mc.GetPreferredInstaller(localManifest);
+
+        // Exe is in the default list; Zip is not — Exe should be preferred.
+        RequireInstaller(result, localExe);
+        REQUIRE(inapplicabilities.size() == 0);
+    }
 }
 
 TEST_CASE("ManifestComparator_MachineArchitecture_Strong_Scope_Weak", "[manifest_comparator]")

src/AppInstallerCommonCore/Manifest/ManifestComparator.cpp

@@ -228,6 +228,22 @@ namespace AppInstaller::Manifest
                 {
                     preference = Settings::User().Get<Settings::Setting::InstallerTypePreference>();
                     requirement = Settings::User().Get<Settings::Setting::InstallerTypeRequirement>();
+
+                    // Apply default precedence order when the user has not configured any installer type preferences or requirements.
+                    if (preference.empty() && requirement.empty())
+                    {
+                        preference = {
+                            InstallerTypeEnum::MSStore,
+                            InstallerTypeEnum::Msix,
+                            InstallerTypeEnum::Msi,
+                            InstallerTypeEnum::Wix,
+                            InstallerTypeEnum::Burn,
+                            InstallerTypeEnum::Nullsoft,
+                            InstallerTypeEnum::Inno,
+                            InstallerTypeEnum::Exe,
+                            InstallerTypeEnum::Portable,
+                        };
+                    }
                 }
 
                 if (!preference.empty() || !requirement.empty())