[Backport 1.5.latest] Initialize sqlparse lexer and tweak order of setting compilation fields

.changes/unreleased/Fixes-20230726-104448.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Improve handling of CTE injection with ephemeral models
+time: 2023-07-26T10:44:48.888451-04:00
+custom:
+  Author: gshank
+  Issue: "8213"

core/dbt/compilation.py

@@ -323,16 +323,16 @@ def _recursively_prepend_ctes(
 
             _add_prepended_cte(prepended_ctes, InjectedCTE(id=cte.id, sql=sql))
 
-        injected_sql = self._inject_ctes_into_sql(
-            model.compiled_code,
-            prepended_ctes,
-        )
         # Check again before updating for multi-threading
         if not model.extra_ctes_injected:
+            injected_sql = self._inject_ctes_into_sql(
+                model.compiled_code,
+                prepended_ctes,
+            )
+            model.extra_ctes_injected = True
             model._pre_injected_sql = model.compiled_code
             model.compiled_code = injected_sql
             model.extra_ctes = prepended_ctes
-            model.extra_ctes_injected = True
 
         # if model.extra_ctes is not set to prepended ctes, something went wrong
         return model, model.extra_ctes
@@ -523,6 +523,12 @@ def compile_node(
         the node's raw_code into compiled_code, and then calls the
         recursive method to "prepend" the ctes.
         """
+        # Make sure Lexer for sqlparse 0.4.4 is initialized
+        from sqlparse.lexer import Lexer  # type: ignore
+
+        if hasattr(Lexer, "get_default_instance"):
+            Lexer.get_default_instance()
+
         node = self._compile_code(node, manifest, extra_context)
 
         node, _ = self._recursively_prepend_ctes(node, manifest, extra_context)