Merge pull request #176 from felicity-semmle/1.18/csharp-change-notes

LGTM 1.18: finalize change notes for C#

Author: hvitved

change-notes/1.18/analysis-csharp.md

@@ -1,11 +1,5 @@
 # Improvements to C# analysis
 
-> NOTES
->
-> Please describe your changes in terms that are suitable for
-> customers to read. These notes will have only minor tidying up
-> before they are published as part of the release notes.
-
 ## General improvements
 
 * Control flow analysis has been improved for `catch` clauses with filters.
@@ -14,38 +8,37 @@
 
 | **Query**                   | **Tags**  | **Purpose**                                                        |
 |-----------------------------|-----------|--------------------------------------------------------------------|
-| Arbitrary file write during zip extraction ("Zip Slip") (`cs/zipslip`) | security, external/cwe/cwe-022  | Identifies zip extraction routines which allow arbitrary file overwrite vulnerabilities.
+| Arbitrary file write during zip extraction ("Zip Slip") (`cs/zipslip`) | security, external/cwe/cwe-022  | Identifies zip extraction routines which allow arbitrary file overwrite vulnerabilities. |
 | Local scope variable shadows member (`cs/local-shadows-member`) | maintainability, readability | Replaces the existing queries Local variable shadows class member (`cs/local-shadows-class-member`), Local variable shadows struct member (`cs/local-shadows-struct-member`), Parameter shadows class member (`cs/parameter-shadows-class-member`), and Parameter shadows struct member (`cs/parameter-shadows-struct-member`). |
 
 ## Changes to existing queries
 
 | **Query**                  | **Expected impact**    | **Change**                                                       |
 |----------------------------|------------------------|------------------------------------------------------------------|
-| [Constant condition](https://help.semmle.com/wiki/display/CSHARP/Constant+condition) (`cs/constant-condition`) | More results | The query has been generalized to cover both Null-coalescing left operand is constant (`cs/constant-null-coalescing`) and Switch selector is constant (`cs/constant-switch-selector`). |
+| Constant condition (`cs/constant-condition`) | More results | The query has been generalized to report alerts for the old queries Null-coalescing left operand is constant (`cs/constant-null-coalescing`) and Switch selector is constant (`cs/constant-switch-selector`). |
 | Exposing internal representation (`cs/expose-implementation`) | Different results | The query has been rewritten, based on the [equivalent Java query](https://help.semmle.com/wiki/display/JAVA/Exposing+internal+representation). |
-| Local variable shadows class member(`cs/local-shadows-class-member`) | No results | The query has been replaced by Local scope variable shadows member  (`cs/local-shadows-member`). |
-| Local variable shadows struct member (`cs/local-shadows-struct-member`) | No results | The query has been replaced by Local scope variable shadows member  (`cs/local-shadows-member`). |
-| [Missing Dispose call on local IDisposable](https://help.semmle.com/wiki/display/CSHARP/Missing+Dispose+call+on+local+IDisposable) (`cs/local-not-disposed`) | Fewer results | The query identifies more cases where the local variable may be disposed by a library call. |
-| [Nested loops with same variable](https://help.semmle.com/wiki/display/CSHARP/Nested+loops+with+same+variable) (`cs/nested-loops-with-same-variable`) | Fewer results | Results are no longer highlighted in nested loops that share the same condition, and do not use the variable after the inner loop. |
-| Null-coalescing left operand is constant (`cs/constant-null-coalescing`) | No results | The query has been removed, as it is now covered by Constant condition (`cs/constant-condition`). |
-| Parameter shadows class member (`cs/parameter-shadows-class-member`) | No results | The query has been replaced by Local scope variable shadows member  (`cs/local-shadows-member`). |
-| Parameter shadows struct member (`cs/parameter-shadows-struct-member`) | No results | The query has been replaced by Local scope variable shadows member  (`cs/local-shadows-member`). |
-| [Potentially incorrect CompareTo(...) signature](https://help.semmle.com/wiki/display/CSHARP/Potentially+incorrect+CompareTo%28...%29+signature) (`cs/wrong-compareto-signature`) | Fewer results | Results are no longer highlighted in constructed types. |
-| Switch selector is constant (`cs/constant-switch-selector`) | No results | The query has been removed, as it is now covered by Constant condition (`cs/constant-condition`). |
-| [Useless upcast](https://help.semmle.com/wiki/display/CSHARP/Useless+upcast) (`cs/useless-upcast`) | Fewer results | The query has been improved to cover more cases where upcasts may be needed. |
+| Local variable shadows class member (`cs/local-shadows-class-member`) | No results | The query has been replaced by the new query: Local scope variable shadows member  (`cs/local-shadows-member`). |
+| Local variable shadows struct member (`cs/local-shadows-struct-member`) | No results | The query has been replaced by the new query: Local scope variable shadows member  (`cs/local-shadows-member`). |
+| Missing Dispose call on local IDisposable (`cs/local-not-disposed`) | Fewer false positive results | The query identifies more cases where the local variable may be disposed by a library call. |
+| Nested loops with same variable (`cs/nested-loops-with-same-variable`) | Fewer false positive results | Results are no longer highlighted in nested loops that share the same condition, and do not use the variable after the inner loop. |
+| Null-coalescing left operand is constant (`cs/constant-null-coalescing`) | No results | The query has been removed, as alerts for this problem are now reported by the new query: Constant condition (`cs/constant-condition`). |
+| Parameter shadows class member (`cs/parameter-shadows-class-member`) | No results | The query has been replaced by the new query: Local scope variable shadows member  (`cs/local-shadows-member`). |
+| Parameter shadows struct member (`cs/parameter-shadows-struct-member`) | No results | The query has been replaced by the new query: Local scope variable shadows member  (`cs/local-shadows-member`). |
+| Potentially incorrect CompareTo(...) signature (`cs/wrong-compareto-signature`) | Fewer false positive results | Results are no longer highlighted in constructed types. |
+| Switch selector is constant (`cs/constant-switch-selector`) | No results | The query has been removed, as alerts for this problem are now reported by the new query: Constant condition (`cs/constant-condition`). |
+| Useless upcast (`cs/useless-upcast`) | Fewer false positive results | The query has been improved to cover more cases where upcasts may be needed. |
 
 ## Changes to code extraction
 
 * The `into` part of `join` clauses is now extracted.
 * The `when` part of constant cases is now extracted.
 * Fixed a bug where `while(x is T y) ...` was not extracted correctly.
 
-* *Series of bullet points*
-
 ## Changes to QL libraries
 
-* A new non-member predicate `mayBeDisposed()` can be used to determine if a variable is potentially disposed inside a library. It will analyse the CIL code in the library to determine this.
-* Several control flow graph entities have been renamed (the old names still exist for backwards compatibility):
+* A new non-member predicate `mayBeDisposed()` can be used to determine if a variable is potentially disposed inside a library. It will analyze the CIL code in the library to determine this.
+* The predicate `getCondition()` has been moved from `TypeCase` to `CaseStmt`. It is now possible to get the condition of a `ConstCase` using its `getCondition()` predicate.
+* Several control flow graph entities have been renamed (the old names are deprecated but are still available in this release for backwards compatibility):
   - `ControlFlowNode` has been renamed to `ControlFlow::Node`.
   - `CallableEntryNode` has been renamed to `ControlFlow::Nodes::EntryNode`.
   - `CallableExitNode` has been renamed to `ControlFlow::Nodes::ExitNode`.
@@ -63,4 +56,5 @@
   - `ControlFlowEdgeGotoCase` has been renamed to `ControlFlow::SuccessorTypes::GotoCaseSuccessor`.
   - `ControlFlowEdgeGotoDefault` has been renamed to `ControlFlow::SuccessorTypes::GotoDefaultSuccessor`.
   - `ControlFlowEdgeException` has been renamed to `ControlFlow::SuccessorTypes::ExceptionSuccessor`.
-* The predicate `getCondition()` has been moved from `TypeCase` to `CaseStmt`. It is now possible to get the condition of a `ConstCase` using its `getCondition()` predicate.
+
+> You should update any custom queries that use these entities to ensure that they continue working when the old names are removed in a future release.