From d15286103648b5cbfadfc6eeec132f224b49e2ec Mon Sep 17 00:00:00 2001
From: PJ Fanning <fanningpj@apache.org>
Date: Thu, 10 Aug 2023 09:38:39 +0000
Subject: [PATCH] [bug-66855] Formula parser incorrectly handles sheet name
 containing multiple single quotes in a row. Thanks to Kirill lebedev. This
 closes #496

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1911589 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/poi/ss/formula/FormulaParser.java |  2 --
 .../apache/poi/hssf/model/TestFormulaParser.java | 16 ++++++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java b/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
index 83fe1051af..28d13bfbc8 100644
--- a/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
+++ b/poi/src/main/java/org/apache/poi/ss/formula/FormulaParser.java
@@ -1182,8 +1182,6 @@ public final class FormulaParser {
                         if (look == '\''){
                             // Any single quotes which were already present in the sheet name will be converted to double single quotes ('')
                             // so switch back to single quote
-                            sb.appendCodePoint(look);
-                            nextChar();
                             break;
                         }
                     }
diff --git a/poi/src/test/java/org/apache/poi/hssf/model/TestFormulaParser.java b/poi/src/test/java/org/apache/poi/hssf/model/TestFormulaParser.java
index 2a3cb6c98c..40c96991bf 100644
--- a/poi/src/test/java/org/apache/poi/hssf/model/TestFormulaParser.java
+++ b/poi/src/test/java/org/apache/poi/hssf/model/TestFormulaParser.java
@@ -1371,6 +1371,22 @@ final class TestFormulaParser {
         wb.close();
     }
 
+    @Test
+    void testParseSheetNameWithMultipleSingleQuotes() throws IOException {
+        try (HSSFWorkbook wb = new HSSFWorkbook()) {
+            wb.createSheet("Sh''t1");
+            Ptg[] ptgs = parse("'Sh''''t1'!$A:$A,'Sh''''t1'!$1:$4", wb);
+            confirmTokenClasses(ptgs,
+                    MemFuncPtg.class,
+                    Area3DPtg.class,
+                    Area3DPtg.class,
+                    UnionPtg.class
+            );
+            assertEquals(0, ((Area3DPtg)ptgs[1]).getExternSheetIndex());
+            assertEquals(0, ((Area3DPtg)ptgs[2]).getExternSheetIndex());
+        }
+    }
+
     @Test
     void testExplicitRangeWithTwoSheetNames() throws IOException {
         HSSFWorkbook wb = new HSSFWorkbook();