From 2e8b5f743b5b1e807db73d775ab78a5920346fd5 Mon Sep 17 00:00:00 2001
From: Jonathan Leitschuh <Jonathan.Leitschuh@gmail.com>
Date: Mon, 7 Mar 2022 20:02:23 -0500
Subject: [PATCH 1/5] [Java] Add CompileTimeConstantExpr.getStringified method

Removes CharacterLiteral from CompileTimeConstantExpr.getStringValue

Resolves:
 - https://github.com/github/codeql/pull/8325#issuecomment-1060470279
 - https://github.com/github/codeql/pull/8325#issuecomment-1060587205
---
 ...3-char-literal-in-compile-time-constant.md |   4 -
 ...7-char-literal-in-compile-time-constant.md |   5 +
 java/ql/lib/semmle/code/java/Expr.qll         |  50 +++++-
 .../library-tests/constants/PrintAst.expected | 151 ++++++++++++++++++
 .../constants/constants/Stringified.java      |  28 ++++
 .../constants/constants/Values.java           |   2 +
 .../constants/getIntValue.expected            |   1 +
 .../library-tests/constants/getIntValue.ql    |   2 +-
 .../constants/getStringValue.expected         |  24 ++-
 .../library-tests/constants/getStringValue.ql |   2 +-
 .../constants/getStringified.expected         |  80 ++++++++++
 .../library-tests/constants/getStringified.ql |   9 ++
 12 files changed, 346 insertions(+), 12 deletions(-)
 delete mode 100644 java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
 create mode 100644 java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
 create mode 100644 java/ql/test/library-tests/constants/constants/Stringified.java
 create mode 100644 java/ql/test/library-tests/constants/getStringified.expected
 create mode 100644 java/ql/test/library-tests/constants/getStringified.ql

diff --git a/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
deleted file mode 100644
index 1ee68add8b14..000000000000
--- a/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
+++ /dev/null
@@ -1,4 +0,0 @@
----
-category: minorAnalysis
----
- * Add support for `CharacterLiteral` in `CompileTimeConstantExpr.getStringValue()`
diff --git a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
new file mode 100644
index 000000000000..5be27c4f8f1a
--- /dev/null
+++ b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
@@ -0,0 +1,5 @@
+---
+category: minorAnalysis
+---
+ * Add new method `CharacterLiteral.getStringifiedValue` which attempts to compute the
+   `String.valueOf` compile time constant value of the expression.
diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
index d98cdbb6b0e6..fe75761fb088 100755
--- a/java/ql/lib/semmle/code/java/Expr.qll
+++ b/java/ql/lib/semmle/code/java/Expr.qll
@@ -161,6 +161,38 @@ class CompileTimeConstantExpr extends Expr {
     )
   }
 
+  /**
+   * Gets the stringified value of this expression, where possible.
+   *
+   * The stringified version of a compile-time constant expression is the equivalent to
+   * the result of calling `String.valueOf(expr)` on the expression.
+   * 
+   * Note that this does not handle the following cases:
+   *
+   * - mathematical computations of type `long`.
+   */
+  pragma[nomagic]
+  string getStringifiedValue() {
+    result = getStringValue()
+    or
+    result = this.(Literal).getValue()
+    or
+    result = this.getBooleanValue().toString()
+    or
+    result = this.getIntValue().toString()
+    or
+    // Ternary conditional, with compile-time constant condition.
+    exists(ConditionalExpr ce, boolean condition |
+      ce = this and
+      condition = ce.getCondition().(CompileTimeConstantExpr).getBooleanValue() and
+      result = ce.getBranchExpr(condition).(CompileTimeConstantExpr).getStringifiedValue()
+    )
+    or
+    exists(Variable v | this = v.getAnAccess() |
+      result = v.getInitializer().(CompileTimeConstantExpr).getStringifiedValue()
+    )
+  }
+
   /**
    * Gets the string value of this expression, where possible.
    */
@@ -168,11 +200,19 @@ class CompileTimeConstantExpr extends Expr {
   string getStringValue() {
     result = this.(StringLiteral).getValue()
     or
-    result = this.(CharacterLiteral).getValue()
-    or
-    result =
-      this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringValue() +
-        this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringValue()
+    (
+      if this.(AddExpr).getAnOperand().getType() instanceof TypeString // If either operand type is already a String:
+      then
+        // Then the stringified version of the expression can be safely used as a String will be created.
+        result =
+          this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringifiedValue() +
+            this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringifiedValue()
+      else
+        // Adding two literals of primitive type will not result in a String.
+        result =
+          this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringValue() +
+            this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringValue()
+    )
     or
     // Ternary conditional, with compile-time constant condition.
     exists(ConditionalExpr ce, boolean condition |
diff --git a/java/ql/test/library-tests/constants/PrintAst.expected b/java/ql/test/library-tests/constants/PrintAst.expected
index 2ecc471d9811..fa7a14c94257 100644
--- a/java/ql/test/library-tests/constants/PrintAst.expected
+++ b/java/ql/test/library-tests/constants/PrintAst.expected
@@ -133,6 +133,151 @@ constants/Initializers.java:
 #   37|         0: [AssignExpr] ...=...
 #   37|           0: [VarAccess] f
 #   37|           1: [IntegerLiteral] 42
+constants/Stringified.java:
+#    0| [CompilationUnit] Stringified
+#    3|   1: [Class] Stringified
+#    4|     2: [Method] stringified
+#    4|       3: [TypeAccess] void
+#-----|       4: (Parameters)
+#    4|         0: [Parameter] notConstant
+#    4|           0: [TypeAccess] String
+#    4|       5: [BlockStmt] { ... }
+#    5|         0: [LocalVariableDeclStmt] var ...;
+#    5|           0: [TypeAccess] String
+#    5|           1: [LocalVariableDeclExpr] withNotConstant
+#    5|             0: [AddExpr] ... + ...
+#    5|               0: [StringLiteral] "a"
+#    5|               1: [VarAccess] notConstant
+#    6|         1: [LocalVariableDeclStmt] var ...;
+#    6|           0: [TypeAccess] String
+#    6|           1: [LocalVariableDeclExpr] string
+#    6|             0: [StringLiteral] "a" + "b"
+#    7|         2: [LocalVariableDeclStmt] var ...;
+#    7|           0: [TypeAccess] String
+#    7|           1: [LocalVariableDeclExpr] stringWithChar
+#    7|             0: [AddExpr] ... + ...
+#    7|               0: [StringLiteral] "ab"
+#    7|               1: [CharacterLiteral] 'c'
+#    8|         3: [LocalVariableDeclStmt] var ...;
+#    8|           0: [TypeAccess] String
+#    8|           1: [LocalVariableDeclExpr] stringWithBool
+#    8|             0: [AddExpr] ... + ...
+#    8|               0: [StringLiteral] "ab"
+#    8|               1: [BooleanLiteral] true
+#    9|         4: [LocalVariableDeclStmt] var ...;
+#    9|           0: [TypeAccess] String
+#    9|           1: [LocalVariableDeclExpr] stringWithInt
+#    9|             0: [AddExpr] ... + ...
+#    9|               0: [StringLiteral] "ab"
+#    9|               1: [IntegerLiteral] 42
+#   10|         5: [LocalVariableDeclStmt] var ...;
+#   10|           0: [TypeAccess] String
+#   10|           1: [LocalVariableDeclExpr] stringWithDouble
+#   10|             0: [AddExpr] ... + ...
+#   10|               0: [StringLiteral] "ab"
+#   10|               1: [DoubleLiteral] 43.0
+#   11|         6: [LocalVariableDeclStmt] var ...;
+#   11|           0: [TypeAccess] String
+#   11|           1: [LocalVariableDeclExpr] stringWithFloat
+#   11|             0: [AddExpr] ... + ...
+#   11|               0: [StringLiteral] "ab"
+#   11|               1: [FloatingPointLiteral] 44.0f
+#   12|         7: [LocalVariableDeclStmt] var ...;
+#   12|           0: [TypeAccess] String
+#   12|           1: [LocalVariableDeclExpr] stringWithLong
+#   12|             0: [AddExpr] ... + ...
+#   12|               0: [StringLiteral] "ab"
+#   12|               1: [LongLiteral] 45L
+#   13|         8: [LocalVariableDeclStmt] var ...;
+#   13|           0: [TypeAccess] String
+#   13|           1: [LocalVariableDeclExpr] stringWithShort
+#   13|             0: [AddExpr] ... + ...
+#   13|               0: [StringLiteral] "ab"
+#   13|               1: [CastExpr] (...)...
+#   13|                 0: [TypeAccess] short
+#   13|                 1: [IntegerLiteral] 46
+#   14|         9: [LocalVariableDeclStmt] var ...;
+#   14|           0: [TypeAccess] String
+#   14|           1: [LocalVariableDeclExpr] stringWithByte
+#   14|             0: [AddExpr] ... + ...
+#   14|               0: [StringLiteral] "ab"
+#   14|               1: [CastExpr] (...)...
+#   14|                 0: [TypeAccess] byte
+#   14|                 1: [IntegerLiteral] 47
+#   15|         10: [LocalVariableDeclStmt] var ...;
+#   15|           0: [TypeAccess] String
+#   15|           1: [LocalVariableDeclExpr] charWithString
+#   15|             0: [AddExpr] ... + ...
+#   15|               0: [CharacterLiteral] 'a'
+#   15|               1: [StringLiteral] "bc"
+#   16|         11: [LocalVariableDeclStmt] var ...;
+#   16|           0: [TypeAccess] String
+#   16|           1: [LocalVariableDeclExpr] boolWithString
+#   16|             0: [AddExpr] ... + ...
+#   16|               0: [BooleanLiteral] true
+#   16|               1: [StringLiteral] "bc"
+#   17|         12: [LocalVariableDeclStmt] var ...;
+#   17|           0: [TypeAccess] String
+#   17|           1: [LocalVariableDeclExpr] intWithString
+#   17|             0: [AddExpr] ... + ...
+#   17|               0: [IntegerLiteral] 42
+#   17|               1: [StringLiteral] "bc"
+#   18|         13: [LocalVariableDeclStmt] var ...;
+#   18|           0: [TypeAccess] String
+#   18|           1: [LocalVariableDeclExpr] doubleWithString
+#   18|             0: [AddExpr] ... + ...
+#   18|               0: [DoubleLiteral] 43.0
+#   18|               1: [StringLiteral] "bc"
+#   19|         14: [LocalVariableDeclStmt] var ...;
+#   19|           0: [TypeAccess] String
+#   19|           1: [LocalVariableDeclExpr] floatWithString
+#   19|             0: [AddExpr] ... + ...
+#   19|               0: [FloatingPointLiteral] 44.0f
+#   19|               1: [StringLiteral] "bc"
+#   20|         15: [LocalVariableDeclStmt] var ...;
+#   20|           0: [TypeAccess] String
+#   20|           1: [LocalVariableDeclExpr] longWithString
+#   20|             0: [AddExpr] ... + ...
+#   20|               0: [LongLiteral] 45L
+#   20|               1: [StringLiteral] "bc"
+#   21|         16: [LocalVariableDeclStmt] var ...;
+#   21|           0: [TypeAccess] String
+#   21|           1: [LocalVariableDeclExpr] shortWithString
+#   21|             0: [AddExpr] ... + ...
+#   21|               0: [CastExpr] (...)...
+#   21|                 0: [TypeAccess] short
+#   21|                 1: [IntegerLiteral] 46
+#   21|               1: [StringLiteral] "bc"
+#   22|         17: [LocalVariableDeclStmt] var ...;
+#   22|           0: [TypeAccess] String
+#   22|           1: [LocalVariableDeclExpr] byteWithString
+#   22|             0: [AddExpr] ... + ...
+#   22|               0: [CastExpr] (...)...
+#   22|                 0: [TypeAccess] byte
+#   22|                 1: [IntegerLiteral] 47
+#   22|               1: [StringLiteral] "bc"
+#   24|         18: [LocalVariableDeclStmt] var ...;
+#   24|           0: [TypeAccess] String
+#   24|           1: [LocalVariableDeclExpr] stringWithExponent
+#   24|             0: [AddExpr] ... + ...
+#   24|               0: [StringLiteral] "a"
+#   24|               1: [DoubleLiteral] 10e1
+#   25|         19: [LocalVariableDeclStmt] var ...;
+#   25|           0: [TypeAccess] String
+#   25|           1: [LocalVariableDeclExpr] stringWithBooleanOr
+#   25|             0: [AddExpr] ... + ...
+#   25|               0: [StringLiteral] "a"
+#   25|               1: [OrLogicalExpr] ... || ...
+#   25|                 0: [BooleanLiteral] true
+#   25|                 1: [BooleanLiteral] false
+#   26|         20: [LocalVariableDeclStmt] var ...;
+#   26|           0: [TypeAccess] String
+#   26|           1: [LocalVariableDeclExpr] stringWithIntDivide
+#   26|             0: [AddExpr] ... + ...
+#   26|               0: [StringLiteral] "a"
+#   26|               1: [DivExpr] ... / ...
+#   26|                 0: [IntegerLiteral] 168
+#   26|                 1: [IntegerLiteral] 4
 constants/Values.java:
 #    0| [CompilationUnit] Values
 #    4|   1: [Class] Values
@@ -526,3 +671,9 @@ constants/Values.java:
 #   92|             0: [AddExpr] ... + ...
 #   92|               0: [StringLiteral] "ab"
 #   92|               1: [CharacterLiteral] 'c'
+#   94|         70: [LocalVariableDeclStmt] var ...;
+#   94|           0: [TypeAccess] int
+#   94|           1: [LocalVariableDeclExpr] charWithChar
+#   94|             0: [AddExpr] ... + ...
+#   94|               0: [CharacterLiteral] 'a'
+#   94|               1: [CharacterLiteral] 'b'
diff --git a/java/ql/test/library-tests/constants/constants/Stringified.java b/java/ql/test/library-tests/constants/constants/Stringified.java
new file mode 100644
index 000000000000..b8836a2f0f64
--- /dev/null
+++ b/java/ql/test/library-tests/constants/constants/Stringified.java
@@ -0,0 +1,28 @@
+package constants;
+
+public class Stringified {
+    void stringified(final String notConstant) {
+        String withNotConstant = "a" + notConstant;
+        String string = "a" + "b"; //ab
+        String stringWithChar = "ab" + 'c'; //abc
+        String stringWithBool = "ab" + true; //abtrue
+        String stringWithInt = "ab" + 42; //ab42
+        String stringWithDouble = "ab" + 43.0; //ab43.0
+        String stringWithFloat = "ab" + 44.0f; //ab44.0
+        String stringWithLong = "ab" + 45L; //ab45
+        String stringWithShort = "ab" + (short) 46; //ab46
+        String stringWithByte = "ab" + (byte) 47; //ab47
+        String charWithString = 'a' + "bc"; //abc
+        String boolWithString = true + "bc"; //truebc
+        String intWithString = 42 + "bc"; //42bc
+        String doubleWithString = 43.0 + "bc"; //43.0bc
+        String floatWithString = 44.0f + "bc"; //44.0bc
+        String longWithString = 45L + "bc"; //45bc
+        String shortWithString = (short) 46 + "bc"; //46bc
+        String byteWithString = (byte) 47 + "bc"; //47bc
+
+        String stringWithExponent = "a" + 10e1; //a100
+        String stringWithBooleanOr = "a" + (true || false); //atrue
+        String stringWithIntDivide = "a" + (168 / 4); //a42
+    }
+}
diff --git a/java/ql/test/library-tests/constants/constants/Values.java b/java/ql/test/library-tests/constants/constants/Values.java
index b59672f96e75..0f838176202c 100644
--- a/java/ql/test/library-tests/constants/constants/Values.java
+++ b/java/ql/test/library-tests/constants/constants/Values.java
@@ -90,5 +90,7 @@ void values(final int notConstant) {
         int var_nonfinald_local = var_field; //Not constant
         String concatenatedString = "a" + "b"; //ab
         String concatenatedChar = "ab" + 'c'; //abc
+        
+        int charWithChar = 'a' + 'b'; //195
     }
 }
diff --git a/java/ql/test/library-tests/constants/getIntValue.expected b/java/ql/test/library-tests/constants/getIntValue.expected
index 8dfd0fc7841a..4194479cb130 100644
--- a/java/ql/test/library-tests/constants/getIntValue.expected
+++ b/java/ql/test/library-tests/constants/getIntValue.expected
@@ -37,3 +37,4 @@
 | constants/Values.java:86:25:86:35 | final_field | 42 |
 | constants/Values.java:87:33:87:34 | 42 | 42 |
 | constants/Values.java:88:25:88:35 | final_local | 42 |
+| constants/Values.java:94:28:94:36 | ... + ... | 195 |
diff --git a/java/ql/test/library-tests/constants/getIntValue.ql b/java/ql/test/library-tests/constants/getIntValue.ql
index 5fc5b108032f..0e84c2d1719b 100644
--- a/java/ql/test/library-tests/constants/getIntValue.ql
+++ b/java/ql/test/library-tests/constants/getIntValue.ql
@@ -4,6 +4,6 @@ from Variable v, CompileTimeConstantExpr init, RefType enclosing, int constant
 where
   v.getInitializer() = init and
   init.getEnclosingCallable().getDeclaringType() = enclosing and
-  enclosing.hasQualifiedName("constants", "Values") and
+  enclosing.hasQualifiedName("constants", ["Values", "Stringified"]) and
   constant = init.getIntValue()
 select init, constant
diff --git a/java/ql/test/library-tests/constants/getStringValue.expected b/java/ql/test/library-tests/constants/getStringValue.expected
index b6afeb8052eb..2fdc29e03822 100644
--- a/java/ql/test/library-tests/constants/getStringValue.expected
+++ b/java/ql/test/library-tests/constants/getStringValue.expected
@@ -1,3 +1,25 @@
-| constants/Values.java:19:29:19:31 | '*' | * |
+| constants/Stringified.java:6:25:6:33 | "a" + "b" | ab |
+| constants/Stringified.java:7:33:7:42 | ... + ... | ab99 |
+| constants/Stringified.java:7:33:7:42 | ... + ... | abc |
+| constants/Stringified.java:8:33:8:43 | ... + ... | abtrue |
+| constants/Stringified.java:9:32:9:40 | ... + ... | ab42 |
+| constants/Stringified.java:10:35:10:45 | ... + ... | ab43.0 |
+| constants/Stringified.java:11:34:11:45 | ... + ... | ab44.0 |
+| constants/Stringified.java:12:33:12:42 | ... + ... | ab45 |
+| constants/Stringified.java:13:34:13:50 | ... + ... | ab46 |
+| constants/Stringified.java:14:33:14:48 | ... + ... | ab47 |
+| constants/Stringified.java:15:33:15:42 | ... + ... | 97bc |
+| constants/Stringified.java:15:33:15:42 | ... + ... | abc |
+| constants/Stringified.java:16:33:16:43 | ... + ... | truebc |
+| constants/Stringified.java:17:32:17:40 | ... + ... | 42bc |
+| constants/Stringified.java:18:35:18:45 | ... + ... | 43.0bc |
+| constants/Stringified.java:19:34:19:45 | ... + ... | 44.0bc |
+| constants/Stringified.java:20:33:20:42 | ... + ... | 45bc |
+| constants/Stringified.java:21:34:21:50 | ... + ... | 46bc |
+| constants/Stringified.java:22:33:22:48 | ... + ... | 47bc |
+| constants/Stringified.java:24:37:24:46 | ... + ... | a100.0 |
+| constants/Stringified.java:25:38:25:58 | ... + ... | atrue |
+| constants/Stringified.java:26:38:26:52 | ... + ... | a42 |
 | constants/Values.java:91:37:91:45 | "a" + "b" | ab |
+| constants/Values.java:92:35:92:44 | ... + ... | ab99 |
 | constants/Values.java:92:35:92:44 | ... + ... | abc |
diff --git a/java/ql/test/library-tests/constants/getStringValue.ql b/java/ql/test/library-tests/constants/getStringValue.ql
index bbf7cd8b51e9..2ecb99067b4b 100644
--- a/java/ql/test/library-tests/constants/getStringValue.ql
+++ b/java/ql/test/library-tests/constants/getStringValue.ql
@@ -4,6 +4,6 @@ from Variable v, CompileTimeConstantExpr init, RefType enclosing, string constan
 where
   v.getInitializer() = init and
   init.getEnclosingCallable().getDeclaringType() = enclosing and
-  enclosing.hasQualifiedName("constants", "Values") and
+  enclosing.hasQualifiedName("constants", ["Values", "Stringified"]) and
   constant = init.getStringValue()
 select init, constant
diff --git a/java/ql/test/library-tests/constants/getStringified.expected b/java/ql/test/library-tests/constants/getStringified.expected
new file mode 100644
index 000000000000..a37bcf70543a
--- /dev/null
+++ b/java/ql/test/library-tests/constants/getStringified.expected
@@ -0,0 +1,80 @@
+| constants/Stringified.java:6:25:6:33 | "a" + "b" | ab |
+| constants/Stringified.java:7:33:7:42 | ... + ... | ab99 |
+| constants/Stringified.java:7:33:7:42 | ... + ... | abc |
+| constants/Stringified.java:8:33:8:43 | ... + ... | abtrue |
+| constants/Stringified.java:9:32:9:40 | ... + ... | ab42 |
+| constants/Stringified.java:10:35:10:45 | ... + ... | ab43.0 |
+| constants/Stringified.java:11:34:11:45 | ... + ... | ab44.0 |
+| constants/Stringified.java:12:33:12:42 | ... + ... | ab45 |
+| constants/Stringified.java:13:34:13:50 | ... + ... | ab46 |
+| constants/Stringified.java:14:33:14:48 | ... + ... | ab47 |
+| constants/Stringified.java:15:33:15:42 | ... + ... | 97bc |
+| constants/Stringified.java:15:33:15:42 | ... + ... | abc |
+| constants/Stringified.java:16:33:16:43 | ... + ... | truebc |
+| constants/Stringified.java:17:32:17:40 | ... + ... | 42bc |
+| constants/Stringified.java:18:35:18:45 | ... + ... | 43.0bc |
+| constants/Stringified.java:19:34:19:45 | ... + ... | 44.0bc |
+| constants/Stringified.java:20:33:20:42 | ... + ... | 45bc |
+| constants/Stringified.java:21:34:21:50 | ... + ... | 46bc |
+| constants/Stringified.java:22:33:22:48 | ... + ... | 47bc |
+| constants/Stringified.java:24:37:24:46 | ... + ... | a100.0 |
+| constants/Stringified.java:25:38:25:58 | ... + ... | atrue |
+| constants/Stringified.java:26:38:26:52 | ... + ... | a42 |
+| constants/Values.java:6:29:6:30 | 42 | 42 |
+| constants/Values.java:9:27:9:28 | 42 | 42 |
+| constants/Values.java:10:36:10:46 | -2147483648 | -2147483648 |
+| constants/Values.java:11:29:11:31 | 052 | 42 |
+| constants/Values.java:12:38:12:41 | -... | -42 |
+| constants/Values.java:13:27:13:30 | 0x2A | 42 |
+| constants/Values.java:14:36:14:40 | -... | -42 |
+| constants/Values.java:15:39:15:43 | 0x2_A | 42 |
+| constants/Values.java:16:30:16:37 | 0b101010 | 42 |
+| constants/Values.java:17:39:17:47 | -... | -42 |
+| constants/Values.java:18:42:18:51 | 0b1_0101_0 | 42 |
+| constants/Values.java:19:29:19:31 | '*' | 42 |
+| constants/Values.java:19:29:19:31 | '*' | * |
+| constants/Values.java:20:29:20:31 | 42L | 42 |
+| constants/Values.java:21:35:21:38 | true | true |
+| constants/Values.java:25:20:25:27 | (...)... | 42 |
+| constants/Values.java:26:25:26:33 | (...)... | 42 |
+| constants/Values.java:27:32:27:43 | (...)... | -42 |
+| constants/Values.java:28:32:28:40 | (...)... | 42 |
+| constants/Values.java:29:32:29:41 | (...)... | 42 |
+| constants/Values.java:30:32:30:41 | (...)... | -42 |
+| constants/Values.java:31:32:31:44 | (...)... | 42 |
+| constants/Values.java:32:32:32:44 | (...)... | -32768 |
+| constants/Values.java:33:36:33:44 | (...)... | 42 |
+| constants/Values.java:36:26:36:28 | +... | 42 |
+| constants/Values.java:39:27:39:29 | -... | -42 |
+| constants/Values.java:42:23:42:27 | !... | false |
+| constants/Values.java:43:27:43:28 | ~... | -1 |
+| constants/Values.java:45:19:45:23 | ... * ... | 63 |
+| constants/Values.java:48:19:48:25 | ... / ... | 42 |
+| constants/Values.java:52:19:52:26 | ... % ... | 42 |
+| constants/Values.java:56:20:56:26 | ... + ... | 42 |
+| constants/Values.java:59:21:59:29 | ... - ... | 42 |
+| constants/Values.java:62:22:62:28 | ... << ... | 84 |
+| constants/Values.java:65:22:65:28 | ... >> ... | -1 |
+| constants/Values.java:66:23:66:30 | ... >>> ... | 2147483647 |
+| constants/Values.java:67:27:67:33 | ... & ... | 42 |
+| constants/Values.java:68:26:68:32 | ... \| ... | 42 |
+| constants/Values.java:69:27:69:33 | ... ^ ... | 42 |
+| constants/Values.java:70:23:70:35 | ... && ... | false |
+| constants/Values.java:71:22:71:34 | ... \|\| ... | true |
+| constants/Values.java:72:22:72:28 | ... < ... | false |
+| constants/Values.java:73:22:73:29 | ... <= ... | true |
+| constants/Values.java:74:22:74:28 | ... > ... | false |
+| constants/Values.java:75:23:75:30 | ... >= ... | true |
+| constants/Values.java:76:22:76:29 | ... == ... | true |
+| constants/Values.java:77:22:77:29 | ... != ... | false |
+| constants/Values.java:78:23:78:41 | ...?...:... | false |
+| constants/Values.java:80:23:80:36 | ... == ... | true |
+| constants/Values.java:81:24:81:37 | ... != ... | false |
+| constants/Values.java:83:20:83:21 | 42 | 42 |
+| constants/Values.java:86:25:86:35 | final_field | 42 |
+| constants/Values.java:87:33:87:34 | 42 | 42 |
+| constants/Values.java:88:25:88:35 | final_local | 42 |
+| constants/Values.java:91:37:91:45 | "a" + "b" | ab |
+| constants/Values.java:92:35:92:44 | ... + ... | ab99 |
+| constants/Values.java:92:35:92:44 | ... + ... | abc |
+| constants/Values.java:94:28:94:36 | ... + ... | 195 |
diff --git a/java/ql/test/library-tests/constants/getStringified.ql b/java/ql/test/library-tests/constants/getStringified.ql
new file mode 100644
index 000000000000..5944d117ebf0
--- /dev/null
+++ b/java/ql/test/library-tests/constants/getStringified.ql
@@ -0,0 +1,9 @@
+import semmle.code.java.Variable
+
+from Variable v, CompileTimeConstantExpr init, RefType enclosing, string constant
+where
+  v.getInitializer() = init and
+  init.getEnclosingCallable().getDeclaringType() = enclosing and
+  enclosing.hasQualifiedName("constants", ["Values", "Stringified"]) and
+  constant = init.getStringifiedValue()
+select init, constant

From 65457cc2e29d4e72a5b931915e0b46041819dc09 Mon Sep 17 00:00:00 2001
From: Jonathan Leitschuh <jonathan.leitschuh@gmail.com>
Date: Wed, 9 Mar 2022 10:25:05 -0500
Subject: [PATCH 2/5] Apply suggestions from code review

Co-authored-by: Chris Smowton <smowton@github.com>
---
 ...-03-07-char-literal-in-compile-time-constant.md |  4 ++--
 java/ql/lib/semmle/code/java/Expr.qll              | 14 +++-----------
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
index 5be27c4f8f1a..678c3c7125d9 100644
--- a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
+++ b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
@@ -1,5 +1,5 @@
 ---
 category: minorAnalysis
 ---
- * Add new method `CharacterLiteral.getStringifiedValue` which attempts to compute the
-   `String.valueOf` compile time constant value of the expression.
+ * Add new method `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
+   `String.valueOf` string rendering of a constant expression.
diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
index fe75761fb088..5d8b158f5a1b 100755
--- a/java/ql/lib/semmle/code/java/Expr.qll
+++ b/java/ql/lib/semmle/code/java/Expr.qll
@@ -201,17 +201,9 @@ class CompileTimeConstantExpr extends Expr {
     result = this.(StringLiteral).getValue()
     or
     (
-      if this.(AddExpr).getAnOperand().getType() instanceof TypeString // If either operand type is already a String:
-      then
-        // Then the stringified version of the expression can be safely used as a String will be created.
-        result =
-          this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringifiedValue() +
-            this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringifiedValue()
-      else
-        // Adding two literals of primitive type will not result in a String.
-        result =
-          this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringValue() +
-            this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringValue()
+      this.getType() instanceof TypeString and
+      this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringifiedValue() +
+        this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringifiedValue()
     )
     or
     // Ternary conditional, with compile-time constant condition.

From 363fff23585472e8f12d33027614957fe7274627 Mon Sep 17 00:00:00 2001
From: Jonathan Leitschuh <Jonathan.Leitschuh@gmail.com>
Date: Wed, 9 Mar 2022 10:45:46 -0500
Subject: [PATCH 3/5] Cleanup from code review feedback

---
 ...2022-03-07-char-literal-in-compile-time-constant.md |  2 +-
 java/ql/lib/semmle/code/java/Expr.qll                  | 10 +++++-----
 .../library-tests/constants/CompileTimeConstantExpr.ql |  2 +-
 .../ql/test/library-tests/constants/getBooleanValue.ql |  2 +-
 java/ql/test/library-tests/constants/getInitializer.ql |  2 +-
 java/ql/test/library-tests/constants/getIntValue.ql    |  2 +-
 java/ql/test/library-tests/constants/getStringValue.ql |  2 +-
 java/ql/test/library-tests/constants/getStringified.ql |  2 +-
 8 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
index 678c3c7125d9..b5bf77c33a8c 100644
--- a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
+++ b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
@@ -1,5 +1,5 @@
 ---
 category: minorAnalysis
 ---
- * Add new method `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
+ * Add new predicate `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
    `String.valueOf` string rendering of a constant expression.
diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
index 5d8b158f5a1b..d8824d88cd41 100755
--- a/java/ql/lib/semmle/code/java/Expr.qll
+++ b/java/ql/lib/semmle/code/java/Expr.qll
@@ -166,10 +166,10 @@ class CompileTimeConstantExpr extends Expr {
    *
    * The stringified version of a compile-time constant expression is the equivalent to
    * the result of calling `String.valueOf(expr)` on the expression.
-   * 
+   *
    * Note that this does not handle the following cases:
    *
-   * - mathematical computations of type `long`.
+   * - mathematical computations of type `long`, `float`, or `double`.
    */
   pragma[nomagic]
   string getStringifiedValue() {
@@ -200,11 +200,11 @@ class CompileTimeConstantExpr extends Expr {
   string getStringValue() {
     result = this.(StringLiteral).getValue()
     or
-    (
-      this.getType() instanceof TypeString and
+    this.getType() instanceof TypeString and // When the expression type is `String`
+    result =
+      // Then the resultant string is the addition of both operands stringified value, regardless of type.
       this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringifiedValue() +
         this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringifiedValue()
-    )
     or
     // Ternary conditional, with compile-time constant condition.
     exists(ConditionalExpr ce, boolean condition |
diff --git a/java/ql/test/library-tests/constants/CompileTimeConstantExpr.ql b/java/ql/test/library-tests/constants/CompileTimeConstantExpr.ql
index 93bf17e23b4a..664df880f964 100644
--- a/java/ql/test/library-tests/constants/CompileTimeConstantExpr.ql
+++ b/java/ql/test/library-tests/constants/CompileTimeConstantExpr.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Expr
+import java
 
 from CompileTimeConstantExpr constant, RefType tpe
 where
diff --git a/java/ql/test/library-tests/constants/getBooleanValue.ql b/java/ql/test/library-tests/constants/getBooleanValue.ql
index 460af42d3c30..0d5fa98e4364 100644
--- a/java/ql/test/library-tests/constants/getBooleanValue.ql
+++ b/java/ql/test/library-tests/constants/getBooleanValue.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Variable
+import java
 
 from Variable v, CompileTimeConstantExpr init, RefType enclosing, boolean constant
 where
diff --git a/java/ql/test/library-tests/constants/getInitializer.ql b/java/ql/test/library-tests/constants/getInitializer.ql
index 6e4b28ee938b..dbd0f4515045 100644
--- a/java/ql/test/library-tests/constants/getInitializer.ql
+++ b/java/ql/test/library-tests/constants/getInitializer.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Variable
+import java
 
 from Variable v, Expr init, RefType enclosing
 where
diff --git a/java/ql/test/library-tests/constants/getIntValue.ql b/java/ql/test/library-tests/constants/getIntValue.ql
index 0e84c2d1719b..e1a90be21ab6 100644
--- a/java/ql/test/library-tests/constants/getIntValue.ql
+++ b/java/ql/test/library-tests/constants/getIntValue.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Variable
+import java
 
 from Variable v, CompileTimeConstantExpr init, RefType enclosing, int constant
 where
diff --git a/java/ql/test/library-tests/constants/getStringValue.ql b/java/ql/test/library-tests/constants/getStringValue.ql
index 2ecb99067b4b..f3391bad60a9 100644
--- a/java/ql/test/library-tests/constants/getStringValue.ql
+++ b/java/ql/test/library-tests/constants/getStringValue.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Variable
+import java
 
 from Variable v, CompileTimeConstantExpr init, RefType enclosing, string constant
 where
diff --git a/java/ql/test/library-tests/constants/getStringified.ql b/java/ql/test/library-tests/constants/getStringified.ql
index 5944d117ebf0..4b0dc2c47aa5 100644
--- a/java/ql/test/library-tests/constants/getStringified.ql
+++ b/java/ql/test/library-tests/constants/getStringified.ql
@@ -1,4 +1,4 @@
-import semmle.code.java.Variable
+import java
 
 from Variable v, CompileTimeConstantExpr init, RefType enclosing, string constant
 where

From 3113b276061ba90d20ffecc49174eefbfc6da87a Mon Sep 17 00:00:00 2001
From: Chris Smowton <smowton@github.com>
Date: Thu, 10 Mar 2022 10:03:14 +0000
Subject: [PATCH 4/5] Fix style

---
 java/ql/lib/semmle/code/java/Expr.qll | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/java/ql/lib/semmle/code/java/Expr.qll b/java/ql/lib/semmle/code/java/Expr.qll
index d8824d88cd41..dd85b4586300 100755
--- a/java/ql/lib/semmle/code/java/Expr.qll
+++ b/java/ql/lib/semmle/code/java/Expr.qll
@@ -173,7 +173,7 @@ class CompileTimeConstantExpr extends Expr {
    */
   pragma[nomagic]
   string getStringifiedValue() {
-    result = getStringValue()
+    result = this.getStringValue()
     or
     result = this.(Literal).getValue()
     or

From c99bad4047f2d05465a048bd1e5f38977f28881d Mon Sep 17 00:00:00 2001
From: Tony Torralba <atorralba@users.noreply.github.com>
Date: Fri, 11 Mar 2022 10:34:09 +0100
Subject: [PATCH 5/5] Recover old change note

---
 .../2022-03-03-char-literal-in-compile-time-constant.md     | 4 ++++
 .../2022-03-07-char-literal-in-compile-time-constant.md     | 5 -----
 .../ql/lib/change-notes/2022-03-07-get-stringified-value.md | 6 ++++++
 3 files changed, 10 insertions(+), 5 deletions(-)
 create mode 100644 java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
 delete mode 100644 java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
 create mode 100644 java/ql/lib/change-notes/2022-03-07-get-stringified-value.md

diff --git a/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
new file mode 100644
index 000000000000..1ee68add8b14
--- /dev/null
+++ b/java/ql/lib/change-notes/2022-03-03-char-literal-in-compile-time-constant.md
@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+ * Add support for `CharacterLiteral` in `CompileTimeConstantExpr.getStringValue()`
diff --git a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md b/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
deleted file mode 100644
index b5bf77c33a8c..000000000000
--- a/java/ql/lib/change-notes/2022-03-07-char-literal-in-compile-time-constant.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-category: minorAnalysis
----
- * Add new predicate `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
-   `String.valueOf` string rendering of a constant expression.
diff --git a/java/ql/lib/change-notes/2022-03-07-get-stringified-value.md b/java/ql/lib/change-notes/2022-03-07-get-stringified-value.md
new file mode 100644
index 000000000000..cdb643987029
--- /dev/null
+++ b/java/ql/lib/change-notes/2022-03-07-get-stringified-value.md
@@ -0,0 +1,6 @@
+---
+category: minorAnalysis
+---
+ * Add new predicate `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
+   `String.valueOf` string rendering of a constant expression. This predicate is now used to 
+   compute the string value of an `AddExpr` that has the type `String`.