ftb: added FTB_FORCE_REINSTALL (#2305)

docs/types-and-platforms/mod-platforms/ftb.md

@@ -19,6 +19,8 @@ This mod platform type will automatically take care of downloading and installin
   ```
 - `FTB_MODPACK_VERSION_ID`: optional, the numerical ID of the version to install. If not specified, the latest version will be installed. The "Version ID" can be obtained by hovering over a server file entry and grabbing [this ID in the URL](../../img/ftba-version-id-popup.png).
 
+- `FTB_FORCE_REINSTALL`: if the files become inconsistent, such as when accidentally removing them, the FTB can be forced to re-run by setting this to "true"
+
 ### Upgrading
 
 If a specific `FTB_MODPACK_VERSION_ID` was not specified, simply restart the container to pick up the newest modpack version. If using a specific version ID, recreate the container with the new version ID.

scripts/start-deployFTBA

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+: "${FTB_FORCE_REINSTALL:=false}"
+
 ftbInstallMarker=".ftb-installed"
 
 # shellcheck source=start-utils
@@ -32,7 +34,7 @@ elif ! [[ ${FTB_MODPACK_VERSION_ID} =~ [0-9]+ ]]; then
   exit 1
 fi
 
-if ! [ -f "${ftbInstallMarker}" ] || [ "$(cat "${ftbInstallMarker}")" != "${FTB_MODPACK_ID}=${FTB_MODPACK_VERSION_ID}" ]; then
+if isTrue "$FTB_FORCE_REINSTALL" || ! [ -f "${ftbInstallMarker}" ] || [ "$(cat "${ftbInstallMarker}")" != "${FTB_MODPACK_ID}=${FTB_MODPACK_VERSION_ID}" ]; then
   ftbInstaller=/data/ftb-installer
   if ! [[ -f "${ftbInstaller}" ]]; then
     log "Downloading FTB installer"