Remove unnecessary taint step and update qldoc

java/ql/src/experimental/semmle/code/java/PathSanitizer.qll

@@ -21,12 +21,12 @@ private class ExactStringPathMatchGuard extends PathTraversalBarrierGuard instan
 }
 
 /**
- * Returns the qualifier of a method call if it's a variable access, or the qualifier of the qualifier
- * if the qualifier itself is a method call, which helps to reduce FPs by handling scenarios such as
- * `!uri.getPath().contains("..")`.
+ * Given input `e` = `v.method1(...).method2(...)...`, returns `v` where `v` is a `VarAccess`.
+ *
+ * This is used to look through field accessors such as `uri.getPath()`.
  */
-private Expr getRealQualifier(Expr e) {
-  result = getRealQualifier(e.(MethodAccess).getQualifier())
+private Expr getUnderlyingVarAccess(Expr e) {
+  result = getUnderlyingVarAccess(e.(MethodAccess).getQualifier())
   or
   result = e.(VarAccess)
 }
@@ -37,7 +37,7 @@ private class AllowListGuard extends Guard instanceof MethodAccess {
     not isDisallowedWord(super.getAnArgument())
   }
 
-  Expr getCheckedExpr() { result = getRealQualifier(super.getQualifier()) }
+  Expr getCheckedExpr() { result = getUnderlyingVarAccess(super.getQualifier()) }
 }
 
 /**
@@ -84,7 +84,7 @@ private class BlockListGuard extends Guard instanceof MethodAccess {
     isDisallowedWord(super.getAnArgument())
   }
 
-  Expr getCheckedExpr() { result = getRealQualifier(super.getQualifier()) }
+  Expr getCheckedExpr() { result = getUnderlyingVarAccess(super.getQualifier()) }
 }
 
 /**
@@ -155,7 +155,7 @@ class PathTraversalGuard extends Guard instanceof MethodAccess {
     super.getAnArgument().(CompileTimeConstantExpr).getStringValue() = ".."
   }
 
-  Expr getCheckedExpr() { result = getRealQualifier(super.getQualifier()) }
+  Expr getCheckedExpr() { result = getUnderlyingVarAccess(super.getQualifier()) }
 }
 
 /** A complementary sanitizer that protects against path traversal using path normalization. */