From a7dedf668998ae70d13f15ca01bf400520e21437 Mon Sep 17 00:00:00 2001
From: yangjie01 <yangjie01@baidu.com>
Date: Tue, 21 Jul 2026 19:47:47 +0800
Subject: [PATCH] [MINOR][CORE] Remove dead code across gluten-core

Cleanup pass over `gluten-core` that removes three dead code paths
surfaced by the `Dead code / dead cases` cross-cutting theme from the
earlier L1/L2/L3 review docs. No behavior change on reachable paths.

1. `FloydWarshallGraph.Builder.Impl`: drop the never-read `private var
   graph` field and its two `graph = None` writes in `addVertex` /
   `addEdge`. Remnant of an abandoned build-cache mechanism; the live
   cache is `Transition.factory#graphCache`.

2. `ConfigHelpers.TIME_STRING_PATTERN`: drop the compiled `Pattern`
   plus its `java.util.regex.Pattern` import. `timeFromString`
   delegates to `JavaUtils.timeStringAs`; the regex has no reference.

3. `canPropagateConvention`: rename five unused pattern vars `p` to `_`
   in the `case _: X => true` arms.

Dropped from the initial version after review:
- `GlutenInjector.applier` keeps `val conf = new GlutenCoreConfig(...)`
  since instantiating it forces `GlutenCoreConfig` registration.
- `Transition.Factory#findTransition` keeps the `case _` branch as a
  guard against future additions to the sealed RowType / BatchType
  hierarchy.
---
 .../scala/org/apache/gluten/config/ConfigBuilder.scala |  3 ---
 .../columnar/transition/FloydWarshallGraph.scala       |  3 ---
 .../gluten/extension/columnar/transition/package.scala | 10 +++++-----
 3 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/gluten-core/src/main/scala/org/apache/gluten/config/ConfigBuilder.scala b/gluten-core/src/main/scala/org/apache/gluten/config/ConfigBuilder.scala
index 2c71f46bad1..957f1dcab66 100644
--- a/gluten-core/src/main/scala/org/apache/gluten/config/ConfigBuilder.scala
+++ b/gluten-core/src/main/scala/org/apache/gluten/config/ConfigBuilder.scala
@@ -19,7 +19,6 @@ package org.apache.gluten.config
 import org.apache.spark.network.util.{ByteUnit, JavaUtils}
 
 import java.util.concurrent.TimeUnit
-import java.util.regex.Pattern
 
 object BackendType extends Enumeration {
   type BackendType = Value
@@ -141,8 +140,6 @@ private object ConfigHelpers {
     }
   }
 
-  private val TIME_STRING_PATTERN = Pattern.compile("(-?[0-9]+)([a-z]+)?")
-
   def timeFromString(str: String, unit: TimeUnit): Long = JavaUtils.timeStringAs(str, unit)
 
   def timeToString(v: Long, unit: TimeUnit): String = s"${TimeUnit.MILLISECONDS.convert(v, unit)}ms"
diff --git a/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/FloydWarshallGraph.scala b/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/FloydWarshallGraph.scala
index 00c687d3b6e..1209e6f6ae2 100644
--- a/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/FloydWarshallGraph.scala
+++ b/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/FloydWarshallGraph.scala
@@ -89,12 +89,10 @@ object FloydWarshallGraph {
   private object Builder {
     private class Impl[V <: AnyRef, E <: AnyRef]() extends Builder[V, E] {
       private val pathTable: mutable.Map[V, mutable.Map[V, Path[E]]] = mutable.Map()
-      private var graph: Option[FloydWarshallGraph[V, E]] = None
 
       override def addVertex(v: V): Builder[V, E] = {
         assert(!pathTable.contains(v), s"Vertex $v already exists in graph")
         pathTable.getOrElseUpdate(v, mutable.Map()).getOrElseUpdate(v, Path(Nil))
-        graph = None
         this
       }
 
@@ -104,7 +102,6 @@ object FloydWarshallGraph {
         assert(pathTable.contains(to), s"Vertex $to not exists in graph")
         assert(!hasPath(from, to), s"Path from $from to $to already exists in graph")
         pathTable(from) += to -> Path(Seq(edge))
-        graph = None
         this
       }
 
diff --git a/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/package.scala b/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/package.scala
index e0eb01fc273..ddc2620780a 100644
--- a/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/package.scala
+++ b/gluten-core/src/main/scala/org/apache/gluten/extension/columnar/transition/package.scala
@@ -33,11 +33,11 @@ package object transition {
   //
   // Extend this list in shim layer once Spark has more.
   def canPropagateConvention(plan: SparkPlan): Boolean = plan match {
-    case p: DebugExec => true
-    case p: UnionExec => true
-    case p: AQEShuffleReadExec => true
-    case p: InputAdapter => true
-    case p: WholeStageCodegenExec => true
+    case _: DebugExec => true
+    case _: UnionExec => true
+    case _: AQEShuffleReadExec => true
+    case _: InputAdapter => true
+    case _: WholeStageCodegenExec => true
     case _ => false
   }