Fix bug in line-width control in DAG pretty printer (#1318)

This PR fixes a bug with how the maximum width for pretty printing was not correctly computed. Note that `SqlStringExpression(node_id=str_0 sql_expr='foo')` is longer than expected - this is due to a `__repr__` issue that will be addressed in a follow up.
dbt-labs · Jul 11, 2024 · 2a5985d · 2a5985d
1 parent ea1748f
commit 2a5985d
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Showing 2 changed files with 22 additions and 13 deletions.
diff --git a/metricflow-semantics/metricflow_semantics/dag/dag_to_text.py b/metricflow-semantics/metricflow_semantics/dag/dag_to_text.py
@@ -34,7 +34,7 @@ def __init__(self, max_width: int) -> None:  # noqa: D107
     def update_max_width_for_indented_section(self, indent_prefix: str) -> Iterator[None]:
         """Context manager used to wrap the code that prints an indented section."""
         previous_max_width = self._current_max_width
-        self._current_max_width = max(0, self._current_max_width - len(indent_prefix))
+        self._current_max_width = max(1, self._current_max_width - len(indent_prefix))
         yield None
         self._current_max_width = previous_max_width
 
@@ -101,7 +101,7 @@ def _format_to_text(self, node: DagNode, inner_contents: Optional[str]) -> str:
                 displayed_property.value,
                 # The string representation of displayed_property.value will be wrapped with "<!-- ", " -->" so subtract
                 # the width of those.
-                max_line_length=max_width - len("<!-- ") - len(" -->"),
+                max_line_length=max(1, max_width - len("<!-- ") - len(" -->")),
                 indent_prefix=self._value_indent_prefix,
             )
 

diff --git a/tests_metricflow/mf_logging/test_dag_to_text.py b/tests_metricflow/mf_logging/test_dag_to_text.py
@@ -70,24 +70,33 @@ def _run_mf_pformat() -> None:
         <SqlQueryPlan>
             <SqlSelectStatementNode>
                 <!-- description =  -->
-                <!--   test -->
-                <!-- node_id =  -->
-                <!--   ss_0 -->
-                <!-- col0 =                                                                                        -->
-                <!--   SqlSelectColumn(expr=SqlStringExpression(node_id=str_0 sql_expr='foo'), column_alias='bar') -->
+                <!--   'test' -->
+                <!-- node_id =          -->
+                <!--   NodeId(          -->
+                <!--     id_str='ss_0', -->
+                <!--   )                -->
+                <!-- col0 =                                                      -->
+                <!--   SqlSelectColumn(                                          -->
+                <!--     expr=SqlStringExpression(node_id=str_0 sql_expr='foo'), -->
+                <!--     column_alias='bar',                                     -->
+                <!--   )                                                         -->
                 <!-- from_source =                           -->
                 <!--   SqlTableFromClauseNode(node_id=tfc_0) -->
                 <!-- where =  -->
                 <!--   None -->
                 <!-- distinct =  -->
                 <!--   False -->
                 <SqlTableFromClauseNode>
-                    <!-- description =            -->
-                    <!--   Read from schema.table -->
-                    <!-- node_id =  -->
-                    <!--   tfc_0 -->
-                    <!-- table_id =     -->
-                    <!--   schema.table -->
+                    <!-- description =      -->
+                    <!--   ('Read '         -->
+                    <!--    'from '         -->
+                    <!--    'schema.table') -->
+                    <!-- node_id =           -->
+                    <!--   NodeId(           -->
+                    <!--     id_str='tfc_0', -->
+                    <!--   )                 -->
+                    <!-- table_id =       -->
+                    <!--   'schema.table' -->
                 </SqlTableFromClauseNode>
             </SqlSelectStatementNode>
         </SqlQueryPlan>