Merge pull request #1353 from calumgrant/cs/diagnostic-queries3

C#: Add internal queries for extractor and compiler diagnostics

csharp/ql/src/Diagnostics/CompilerError.qhelp

@@ -0,0 +1,11 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+
+<overview>
+<p>
+This is an internal query that finds all compilation errors reported by the C# compiler used by the C# extractor.</p>
+</overview>
+
+</qhelp>

csharp/ql/src/Diagnostics/CompilerError.ql

@@ -0,0 +1,16 @@
+/**
+ * @name Compilation error
+ * @description A compilation error can cause extraction problems, and could lead to inaccurate results.
+ * @kind problem
+ * @problem.severity recommendation
+ * @precision high
+ * @id cs/compilation-error
+ * @tags internal non-attributable
+ */
+
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+from CompilerError diagnostic
+select diagnostic,
+  diagnostic.getSeverityText() + " " + diagnostic.getTag() + " " + diagnostic.getFullMessage()

csharp/ql/src/Diagnostics/CompilerMessage.qhelp

@@ -0,0 +1,13 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+
+<overview>
+<p>
+This is an internal query that finds all messages reported by the C# compiler used by the C# extractor. This may include both compiler errors and
+compiler warnings.
+</p>
+</overview>
+
+</qhelp>

csharp/ql/src/Diagnostics/CompilerMessage.ql

@@ -0,0 +1,16 @@
+/**
+ * @name Compilation message
+ * @description A message emitted by the compiler, including warnings and errors.
+ * @kind problem
+ * @problem.severity recommendation
+ * @precision high
+ * @id cs/compilation-message
+ * @tags internal non-attributable
+ */
+
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+from Diagnostic diagnostic
+select diagnostic,
+  diagnostic.getSeverityText() + " " + diagnostic.getTag() + " " + diagnostic.getFullMessage()

csharp/ql/src/Diagnostics/ExtractorError.qhelp

@@ -0,0 +1,22 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+
+<overview>
+<p>
+This is an internal query that finds all errors reported by the C# extractor. It excludes results from files containing
+compilation errors, because these errors are likely to be caused by the compilation error rather than due to an internal
+error in the extractor.
+</p>
+
+<p>Extractor errors can lead to inaccurate results.</p>
+</overview>
+
+<recommendation>
+<p>
+Report extractor errors to Semmle.
+</p>
+</recommendation>
+
+</qhelp>

csharp/ql/src/Diagnostics/ExtractorError.ql

@@ -0,0 +1,20 @@
+/**
+ * @name Extraction error
+ * @description An error message reported by the extractor, limited to those files where there are no
+ *              compilation errors. This indicates a bug or limitation in the extractor, and could lead
+ *              to inaccurate results.
+ * @kind problem
+ * @problem.severity recommendation
+ * @precision high
+ * @id cs/extraction-error
+ * @tags internal non-attributable
+ */
+
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+from ExtractorError error
+where not exists(CompilerError ce | ce.getLocation().getFile() = error.getLocation().getFile())
+select error,
+  "Unexpected " + error.getOrigin() + " error in element '" + error.getElementText() +
+    "' at location " + error.getStackTrace()

csharp/ql/src/Diagnostics/ExtractorMessage.qhelp

@@ -0,0 +1,16 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+
+<overview>
+<p>
+This is an internal query that finds all messages reported by the extractor. These results may include extraction errors
+that are caused by compilation errors.
+</p>
+<p>
+Extractor errors can lead to inaccurate results.
+</p>
+</overview>
+
+</qhelp>

csharp/ql/src/Diagnostics/ExtractorMessage.ql

@@ -0,0 +1,17 @@
+/**
+ * @name Extraction message
+ * @description An error message reported by the extractor. This could lead to inaccurate results.
+ * @kind problem
+ * @problem.severity recommendation
+ * @precision high
+ * @id cs/extraction-message
+ * @tags internal non-attributable
+ */
+
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+from ExtractorMessage message
+select message,
+  message.getSeverityText() + " was generated by " + message.getOrigin() + " in element '" +
+    message.getElementText() + "' at location " + message.getStackTrace()

csharp/ql/src/semmle/code/csharp/commons/Diagnostics.qll

@@ -29,6 +29,17 @@ class Diagnostic extends @diagnostic {
    */
   int getSeverity() { result = severity }
 
+  /** Gets a string representation of the severity of this diagnostic. */
+  string getSeverityText() {
+    severity = 0 and result = "Hidden"
+    or
+    severity = 1 and result = "Info"
+    or
+    severity = 2 and result = "Warning"
+    or
+    severity = 3 and result = "Error"
+  }
+
   /** Gets the identifier of this diagnostic, for example "CS8019". */
   string getTag() { result = tag }
 

csharp/ql/test/library-tests/compilations/CompilerError.qlref

@@ -0,0 +1 @@
+Diagnostics/CompilerError.ql

csharp/ql/test/library-tests/compilations/CompilerMessage.expected

@@ -0,0 +1,3 @@
+| Program.cs:7:13:7:13 | CS0219: The variable 'x' is assigned but its value is never used | Warning CS0219 The variable 'x' is assigned but its value is never used |
+| Program.cs:9:9:9:11 | CS0162: Unreachable code detected | Warning CS0162 Unreachable code detected |
+| Program.cs:9:13:9:13 | CS0219: The variable 'y' is assigned but its value is never used | Warning CS0219 The variable 'y' is assigned but its value is never used |

csharp/ql/test/library-tests/compilations/CompilerMessage.qlref

@@ -0,0 +1 @@
+Diagnostics/CompilerMessage.ql

csharp/ql/test/library-tests/compilations/ExtractorError.qlref

@@ -0,0 +1 @@
+Diagnostics/ExtractorError.ql

csharp/ql/test/library-tests/compilations/ExtractorMessage.qlref

@@ -0,0 +1 @@
+Diagnostics/ExtractorMessage.ql