Release notes for checker-XXX builds

# Release notes for `checker-XXX` builds

#### checker-279

built: November 14, 2016 download: checker-279.tar.bz2

highlights:

- The analyzer includes new checks for:
  - Improper instance cleanup up in Objective-C -dealloc methods under manual retain/release.
  - Inadvertent comparisons of NSNumber, CFNumberRef, and other number object pointers against scalar values.
  - Unsafe usage of dispatch_once_t predicates stored in Objective-C instance variables and other heap-allocated memory.
  - Issues resulting from self-assignment in C++.
  - Incorrect usage of MPI APIs in C and C++. This check can be enabled by passing the following command to scan-build:
    `-enable-checker optin.mpi.MPI-Checker`
- The scan-build tool now supports a `--force-analyze-debug-code flag` that forces projects to analyze in debug mode. This flag leaves in assertions and so typically results in fewer false positives.
- Additional miscellaneous improvements.
- Now requires macOS 10.8 or later.

#### checker-278

built: February 5, 2016 download: checker-278.tar.bz2

highlights:

- Greatly improves analysis of C++ lambdas, including interprocedural analysis of lambda applications and reduced 'dead store' false positives for variables captured by reference.
- The analyzer now checks for misuse of 'vfork()'. This check is enabled by default.
- The analyzer can now detect excessively-padded structs. This check can be enabled by passing the following command to scan-build:
  `-enable-checker optin.performance.Padding`
- The checks to detect misuse of `_Nonnull` are now enabled by default.
- The checks to detect misuse of Objective-C generics are now enabled by default.
- Many miscellaneous improvements.

#### checker-277

built: October 28, 2015 download: checker-277.tar.bz2

highlights:

- Includes about 20 months of change to Clang itself.
- New checker for C++ leaks is turned on by default.
- Added various small checks and bug fixes.
- Added experimental checkers for Objective-C:

- New localizability checks:
  - Checker warning about uses of non-localized `NSString`s passed to UI methods expecting localized strings.
  - Checker warning when the comment argument is missing from `NSLocalizedString` macros.
  - These can be enabled by passing the following command to `scan-build`:
    `-enable-checker alpha.osx.cocoa.NonLocalizedStringChecker,alpha.osx.cocoa.EmptyLocalizationContextChecker`
- New checks for `_Nonnull` type qualifiers. These can be enabled with:
  `-enable-checker nullability.NullPassedToNonnull,nullability.NullReturnedFromNonnull`
- New checks for misuse of Objective-C generics. These can be enabled with `-enable-checker alpha.osx.cocoa.ObjCGenerics`.

- Support for `cf_returns_retained` and `cf_returns_not_retained` attributes in out-parameters.
- The analyzer now creates one state for a range switch case instead of multiple, resulting in performance improvements.
- Now requires OS X 10.7 or later.

#### checker-276

built: February 19, 2014 download: checker-276.tar.bz2

highlights:

- Includes about 9 months of change to Clang itself (improved C++11/14 support, etc.)
- More precise modeling of Objective-C properties, which enables the analyzer to find more bugs.
- Includes a new "missing call to `super`" warning, which looks for common pattern in iOS/OSX APIs that require chaining a call to a super class's implementation of a method.
- Accepts `-arch arm64` (which may be passed by Xcode 5.0), but for the time being analyzes code in such cases as `-arch armv7s`.
- Many sundry fixes, improvements to C++ support, etc.

#### checker-275

built: May 23, 2013 download: checker-275.tar.bz2

highlights:

- Xcode: Includes a new arrow layout algorithm for issue presentation within Xcode. The goal is for interprocedural bug reports to look cleaner and less busy (and easier to read). Feedback appreciated.
- Xcode: Bugs that occur within header code (e.g., C++) are now reported within the callers in the main source file. For example, if you misuse a C++ function declared in a header the primary diagnostic will be in the caller (in the main source file). The full expanded path, however, will show the bug in the header code as well. These kind of cross-file issues are currently only support by Xcode, not the HTML output.
- This build is built with LLVM's Link-Time Optimization (LTO), which should make it slightly faster.
- LTO also reduces the download size (about 19% smaller than checker-274).
- Many sundry fixes.

#### checker-274

built: April 23, 2013 download: checker-274.tar.bz2

highlights:

- Improved use-after-free and mismatched deallocator checking.
- Diagnostic polish.
- Fixes crashes found in checker-273.

#### checker-273

built: April 8, 2013 download: checker-273.tar.bz2

highlights:

- Additional checks for misuse of Foundation collection APIs.
- New C++ checker for attempting to create a reference to null.
- New use-after-free checker for C++ 'delete'.
- New checker for simple cases of mismatched allocators and deallocators, e.g. "delete malloc(4);"
- Support for basic interprocedural analysis of C++ destructors.
- Additional heuristics for suppressing null pointer false positives.
- Misc. bug fixes and performance enhancements.

#### checker-272

built: March 1, 2013

highlights:

- Better modeling of C++ constructors:
  - Interprocedural analysis support for constructors of types with trivial destructors
  - Efficient model of trivial copy and move constructors
- Better diagnostics for loops that execute 0 times
- Fixes a linking issue that prevented the checker from running on OS X v10.6 and earlier
- Fixes for misc. crashes and false positives

#### checker-271

built: February 8, 2013

highlights:

- Faster analysis for `scan-build xcodebuild` when using Xcode 4.6 and higher:
  - `scan-build` now uses Xcode's built-in interposition mechanism for the static analyzer to provide faster builds while doing static analysis (PCH files are now built).
  - This change also allows `scan-build` to have better support for iOS project analysis without having to specifying weird SDK settings to `scan-build`.
- Better diagnostics for implicitly-defined member functions in C++.
- New warning for `malloc`/`free` checker when passing `malloc`'ed pointer with non-zero offset to `free()`.
- Fixes for misc. parser crashes.
- Newer than the static analyzer version in Xcode 4.6

#### checker-270

built: January 4, 2013

highlights:

- Major performance enhancements to speed up interprocedural analysis.
- Misc. bug fixes.

#### checker-269

built: September 25, 2012

highlights:

- Significantly improves interprocedural analysis for Objective-C.
- Numerous bug fixes and heuristics to reduce false positives reported over checker-268.

#### checker-268

built: September 11, 2012

highlights:

- Adds initial interprocedural analysis support for C++ and Objective-C. This will greatly improve analysis coverage and find deeper bugs in Objective-C and C++ code.
- Contains a static analyzer newer than Xcode 4.4.

NOTE: this checker build includes a huge number of changes. It has the potential to find many more bugs, but may report new kinds of false positives. We'd like to know about these, and any other problems you encounter. When you encounter an issue, please file a bug report.

#### checker-267

built: June 1, 2012

highlights:

Adds basic interprocedural analysis support for blocks.

#### checker-266

built: May 23, 2012

highlights:

Contains numerous stability fixes over checker-266, especially when analyzing C++11 code.

#### checker-265

built: May 8, 2012

highlights:

This release contains a fix for a major crasher introduced in checker-264, and various refinements to improve the precision and reduce the false positive rate of the analyzer. It also enables a new unix.MallocSizeof check, which reports inconsistencies between the casted type of the return value of a 'malloc/calloc/realloc' call and the operand of sizeof expressions contained within its argument(s).

#### checker-264

built: April 26, 2012

highlights:

This release contains misc. bug fixes and performance enhancements over checker-263, including a reduction of some kinds of false positives related to the malloc() checker.

#### checker-263

built: March 22, 2012

highlights:

- Fixes several serious bugs with inter-procedural analysis, including a case where retain/releases would be "double-counted".

#### checker-262

built: March 15, 2012

highlights:

- Enables experimental interprocedural analysis (within a file), which greatly amplifies the analyzer's ability to find issues.
- Many bug fixes to the malloc/free checker.
- Support for new Objective-C NSArray/NSDictionary/NSNumber literals syntax, and Objective-C container subscripting.

NOTE: This build contains new interprocedural analysis that allows the analyzer to find more complicated bugs that span function boundaries. It may have problems, performance issues, etc. We'd like to hear about them.

#### checker-261

built: February 22, 2012

highlights:

- Contains a new experimental malloc/free checker.
- Better support for projects using ARC.
- Warns about null pointers passed as arguments to C string functions.
- Warns about common anti-patterns in 'strncat' size argument, which can lead to buffer overflows.
- set-xcode-analyzer now supports self-contained Xcode.app (Xcode 4.3 and later).
- Contains a newer version of the analyzer than Xcode 4.3.
- Misc. bug fixes and performance work.

#### checker-260

built: January 25, 2012

highlights:

This is essentially the same as checker-259, but enables the following experimental checkers (please provide feedback):

- Warns about unsafe uses of CFArrayCreate, CFSetCreate, and CFDictionaryCreate
- Warns about unsafe uses of getpw, gets, which are sources of buffer overflows
- Warns about unsafe uses of mktemp and mktemps, which can lead to insecure temporary files
- Warns about unsafe uses of vfork, which is insecure to use
- Warns about not checking the return values of setuid, setgid, seteuid, setegid, setreuid, setregid (another security issue)

#### checker-259

built: January 25, 2012

highlights:

- Contains a newer version of the analyzer than the one shipped in Xcode 4.2.
- Significant performance optimizations to reduce memory usage of the analyzer.
- Tweaks to scan-build to have it work more easily with Xcode projects using Clang.
- Numerous bug fixes to better support code using ARC.

#### checker-258

built: October 13, 2011

highlights:

- Contains a newer version of the analyzer than the one shipped in Xcode 4.2.
- Adds a new security checker for looking at correct uses of the Mac OS KeyChain API.
- Supports ARC (please file bugs where you see issues)
- Major under-the-cover changes. This should result in more precise results in some cases, but this is laying the groundwork for major improvements. Please file bugs where you see regressions or issues.

#### checker-257

built: May 25, 2011

highlights:

- The analyzer is now far more aggressive with checking conformance with Core Foundation conventions. Any function that returns a CF type must now obey the Core Foundation naming conventions, or use the cf_returns_retained or cf_returns_not_retained annotations.
- Fixed a serious regression where the analyzer would not analyze Objective-C methods in class extensions.
- Misc. bug fixes to improve analyzer precision.

#### checker-256

built: April 13, 2011

highlights:

- Lots of bug fixes and improvements to analyzer precision (fewer false positives, possibly more bugs found).
- Introductory analysis support for C++ and Objective-C++.

This build contains basic support for C++ and Objective-C++ that is ready to be tried out by general users. It is still in its infancy, but establishes a baseline for things to come. The main hope is that it can find some issues and have a reasonable false positive rate.

Please file bugs when you see issues of any kind so we can assess where development on C++ analysis support needs to be focused.

To try out C++ analysis support, it should work out of the box using `scan-build`. If you are using this checker build as a replacement to the analyzer bundled with Xcode, first use the `set-xcode-analyzer` script to change Xcode to use your version of the analyzer. You will then need to modify one configuration file in Xcode to enable C++ analysis support. This can be done with the following steps:

1. Find the clang .xcspec file:

       $ cd /Developer/Library
       $ find . | grep xcspec | grep Clang
       ./Xcode/<SNIP>/Clang LLVM 1.0.xcplugin/Contents/Resources/Clang LLVM 1.0.xcspec

2. The exact location of the file may vary depending on your installation of Xcode. Edit that file, and look for the string "--analyze":

         SourceFileOption = "--analyze";
         FileTypes = (
             "sourcecode.c.c",
             "sourcecode.c.objc",
         );
         ...

   Change the "FileTypes" entry to:

         FileTypes = (
             "sourcecode.c.c",
             "sourcecode.c.objc",
             "sourcecode.cpp.cpp",
             "sourcecode.cpp.objcpp",
         );

3. Restart Xcode.

#### checker-255

built: February 11, 2011

highlights:

- Mac OS X builds are now Intel `i386` and `x86_64` only (no `ppc` support)
- Turns on new `-init` method checker by default
- Reduces memory usage of analyzer by 10%
- Misc. fixes to reduce false positives on dead stores and idempotent operations.

#### checker-254

built: January 27, 2011

highlights:

- Introduces new `-init` method checker to check if a super class's init method is properly called.
- Objective-C retain/release checker now reasons about calls to property accessor methods (setter/getter).
- Introduces new attribute ns_consumes_self to educate the Objective-C retain/release checker about custom "init-like" methods that do not follow the standard Cocoa naming conventions.
- Introduces new attributes ns_consumed and cf_consumed to educate the Objective-C retain/release checker about methods/functions that decrement the reference count of a parameter.