refactor: allow missing project.toml

We should treat the project.toml as an optional file, as is the Procfile. Additionally, moving the file into place early will ensure there is no chance of selecting the wrong file.

plugins/builder-pack/builder-build

@@ -1,7 +1,6 @@
 #!/usr/bin/env bash
 source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
 source "$PLUGIN_AVAILABLE_PATH/config/functions"
-source "$PLUGIN_AVAILABLE_PATH/builder-pack/internal-functions"
 set -eo pipefail
 [[ $DOKKU_TRACE ]] && set -x
 
@@ -29,17 +28,6 @@ trigger-builder-pack-builder-build() {
 
   pushd "$SOURCECODE_WORK_DIR" &>/dev/null
 
-  local NEW_PROJECT_TOML="$(fn-builder-pack-computed-projecttoml-path "$APP")"
-  if [[ -n "$NEW_PROJECT_TOML" ]]; then
-    if [[ ! -f "$NEW_PROJECT_TOML" ]] && [[ "$NEW_PROJECT_TOML" != "project.toml" ]]; then
-      dokku_log_fail "Invalid projecttoml-path specified: $NEW_PROJECT_TOML"
-    fi
-
-    if [[ "$NEW_PROJECT_TOML" != "project.toml" ]]; then
-      mv "$NEW_PROJECT_TOML" project.toml
-    fi
-  fi
-
   local TMP_FILE=$(mktemp "/tmp/dokku-${DOKKU_PID}-${FUNCNAME[0]}.XXXXXX")
   trap "rm -rf '$TMP_FILE' >/dev/null" RETURN INT TERM
 

plugins/builder-pack/core-post-extract

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_AVAILABLE_PATH/builder-pack/internal-functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+trigger-builder-pack-core-post-extract() {
+  declare desc="builder-pack post-extract plugin trigger"
+  declare trigger="post-extract"
+  declare APP="$1" SOURCECODE_WORK_DIR="$2"
+  local NEW_PROJECT_TOML="$(fn-builder-pack-computed-projecttoml-path "$APP")"
+
+  pushd "$TMP_WORK_DIR" >/dev/null
+
+  if [[ -z "$NEW_PROJECT_TOML" ]]; then
+    return
+  fi
+
+  if [[ ! -f "$NEW_PROJECT_TOML" ]]; then
+    rm -f project.toml
+    return
+  fi
+
+  if [[ "$NEW_PROJECT_TOML" != "project.toml" ]]; then
+    mv "$NEW_PROJECT_TOML" project.toml
+  fi
+  popd &>/dev/null
+}
+
+trigger-builder-pack-post-extract "$@"