Handle Epic manifest missing MainGameAppName (#357)

* feat: fall back to `AppName` when Epic manifest is missing `MainGameAppName`

tested on epic experimental

* docs: WIP directions on redirecting to local ficsit-cli build

* docs: go replace directive info

* Pin golangci-lint version 2.6.2

* Run formatter

Author: budak7273

.github/workflows/push.yml

@@ -33,7 +33,7 @@ jobs:
 
       - uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.6
+          version: v2.6.2
           only-new-issues: true
 
   lint-frontend:

DEPLOYMENT.md

@@ -9,7 +9,7 @@ Since the build action is triggered on every push to any branch,
 non developers can obtain testing builds easily from [GitHub Actions](https://github.com/satisfactorymodding/SatisfactoryModManager/actions/workflows/push.yml) artifact output.
 You need to be signed into GitHub to download them, and they expire after some time.
 
-TODO how to point dev builds to ficsit.dev (staging) instead?
+To point development builds to ficsit.dev instead of production, see the [Readme's configuration section](./README.md#Configuration).
 
 ## Releases
 

README.md

@@ -51,6 +51,14 @@ If you want to point to the SMR staging API instead of production, edit:
 * `main.go` to set `api-base` to the staging api (`https://api.ficsit.dev`)
 * `frontend\.graphqlrc.yml` to set `schema` to the staging api (`https://api.ficsit.dev/v2/query`)
 
+If you want to use a local build of [ficsit-cli](https://github.com/satisfactorymodding/ficsit-cli),
+use the [Go `replace` directive](https://go.dev/wiki/Modules#when-should-i-use-the-replace-directive) (and do not commit the change),
+for example:
+
+```ps1
+go mod edit -replace github.com/satisfactorymodding/ficsit-cli=C:\Git\ficsit-cli
+```
+
 ### Development Server
 
 The development server will hot reload whenever you make changes to the Go or Typescript code.

backend/installfinders/launchers/epic/epic.go

@@ -13,6 +13,7 @@ type Manifest struct {
 	CatalogNamespace string `json:"CatalogNamespace"`
 	CatalogItemID    string `json:"CatalogItemID"`
 	MainGameAppName  string `json:"MainGameAppName"`
+	AppName          string `json:"AppName"`
 	AppVersionString string `json:"AppVersionString"`
 	InstallLocation  string `json:"InstallLocation"`
 }
@@ -35,7 +36,7 @@ func GetEpicBranch(appName string) (common.GameBranch, error) {
 	case ExperimentalDedicatedServerAppName:
 		return common.BranchExperimental, nil
 	default:
-		return "", fmt.Errorf("unknown branch for %s", appName)
+		return "", fmt.Errorf("unknown branch for '%s'", appName)
 	}
 }
 
@@ -103,6 +104,10 @@ func FindInstallationsEpic(epicManifestsPath string, launcher string, platform c
 		}
 
 		branch, err := GetEpicBranch(epicManifest.MainGameAppName)
+		if err != nil {
+			// Some Epic installs appear to come in with a null MainGameAppName; fall back to AppName
+			branch, err = GetEpicBranch(epicManifest.AppName)
+		}
 		if err != nil {
 			findErrors = append(findErrors, common.InstallFindError{
 				Path:  installLocation,