From 55704b4e65b70a943926fc050a3425dc418dd291 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Tue, 19 Feb 2019 14:00:58 +0100
Subject: [PATCH] [poincare] TreeHandle: the constructor from a identifier
 retains the node if it has one

---
 poincare/include/poincare/expression.h  | 2 +-
 poincare/include/poincare/tree_handle.h | 6 +++++-
 poincare/src/integer.cpp                | 4 +---
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/poincare/include/poincare/expression.h b/poincare/include/poincare/expression.h
index f87d66aa1..b250a00cb 100644
--- a/poincare/include/poincare/expression.h
+++ b/poincare/include/poincare/expression.h
@@ -248,6 +248,7 @@ public:
 protected:
   static bool SimplificationHasBeenInterrupted();
   Expression(const ExpressionNode * n) : TreeHandle(n) {}
+  Expression(int nodeIdentifier) : TreeHandle(nodeIdentifier) {}
   template<typename U>
   static Expression UntypedBuilderOneChild(Expression children) {
     assert(children.type() == ExpressionNode::Type::Matrix);
@@ -284,7 +285,6 @@ protected:
   }
 
   /* Hierarchy */
-  Expression(int nodeIdentifier) : TreeHandle(nodeIdentifier) {}
   Expression parent() const; // TODO try to inline
   void defaultSetChildrenInPlace(Expression other);
   void addChildAtIndexInPlace(TreeHandle t, int index, int currentNumberOfChildren) = delete;
diff --git a/poincare/include/poincare/tree_handle.h b/poincare/include/poincare/tree_handle.h
index abd3008d6..881d95206 100644
--- a/poincare/include/poincare/tree_handle.h
+++ b/poincare/include/poincare/tree_handle.h
@@ -103,7 +103,11 @@ public:
 protected:
   /* Constructor */
   TreeHandle(const TreeNode * node);
-  TreeHandle(int nodeIndentifier = TreeNode::NoNodeIdentifier) : m_identifier(nodeIndentifier) {}
+  TreeHandle(int nodeIndentifier = TreeNode::NoNodeIdentifier) : m_identifier(nodeIndentifier) {
+    if (hasNode(nodeIndentifier)) {
+      node()->retain();
+    }
+  }
   // WARNING: if the children table is the result of a cast, the object downcasted has to be the same size as a TreeHandle.
   static TreeHandle BuildWithBasicChildren(TreeNode * node, TreeHandle * children = nullptr, int numberOfChildren = 0);
 
diff --git a/poincare/src/integer.cpp b/poincare/src/integer.cpp
index 675bf0b44..67fd3e295 100644
--- a/poincare/src/integer.cpp
+++ b/poincare/src/integer.cpp
@@ -107,9 +107,7 @@ Integer::Integer(native_uint_t * digits, uint16_t numberOfDigits, bool negative)
   TreeHandle h = TreeHandle::BuildWithBasicChildren(node);
   /* Integer is a TreeHandle that keeps an extra integer. We cannot just cast
    * the TreeHandle in Integer, we have to build a new Integer. To do so, we
-   * pilfer the TreeHandle identifier. We thus have to increment the node
-   * reference counter to prevent its destruction when we leave this scope. */
-  node->retain();
+   * pilfer the TreeHandle identifier. */
   new (this) Integer(h.identifier(), negative);
 }