Create CHANGELOG for recording changes to absl.

This is so that its easier to find what's changed. Going through the commit
history makes it too hard to figure out what actually changed.

Resolves #93

PiperOrigin-RevId: 236007421

absl/BUILD

@@ -36,7 +36,7 @@ config_setting(
 py_library(
     name = "_enum_module",
     srcs = ["_enum_module.py"],
-    visibility = ["//absl:__subpackages__"],
+    visibility = [":__subpackages__"],
     deps = [
         "@six_archive//:six",
     ] + select({

absl/CHANGELOG.md

@@ -0,0 +1,109 @@
+# Python Absl Changelog
+
+All notable changes to Python Absl are recorded here.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com).
+
+## Unreleased
+
+### Added
+
+*   `flags.mark_bool_flags_as_mutual_exclusive`: convenience function to check
+    that only one, or at most one, flag among a set of boolean flags are True.
+
+## 0.7.0 (2019-01-11)
+
+### Added
+
+*   (bazel) testonly=1 has been removed from the testing libraries, which allows
+    their use outside of testing contexts.
+*   (flags) Multi-flags now accept any Iterable type for the default value
+    instead of only lists. Strings are still special cased as before. This
+    allows sets, generators, views, etc to be used naturally.
+*   (flags) DEFINE_multi_enum_class: a multi flag variant of enum_class.
+*   (testing) Most of absltest is now type-annotated.
+*   (testing) Made AbslTest.assertRegex available under Python 2. This allows
+    Python 2 code to write more natural Python 3 compatible code. (Note: this
+    was actually released in 0.6.1, but unannounced)
+*   (logging) logging.vlog_is_on: helper to tell if a vlog() call will actually
+    log anything. This allows avoiding computing expansive inputs to a logging
+    call when logging isn't enabled for that level.
+
+### Fixed
+
+*   (flags) Pickling flags now raises an clear error instead of a cryptic one.
+    Pickling flags isn't supported; instead use flags_into_string to serialize
+    flags.
+*   (flags) Flags serialization works better: the resulting serialized value,
+    when deserialized, won't cause --help to be invoked, thus ending the
+    process.
+*   (flags) Several flag fixes to make them behave more like the Absl C++ flags:
+    empty --flagfile is allowed; --nohelp and --help=false don't display help
+*   (flags) An empty --flagfile value (e.g. "--flagfile=" or "--flagfile=''"
+    doesn't raise an error; its not just ignored. This matches Abseil C++
+    behavior.
+*   (bazel) Building with Bazel 0.2.0 works without extra incompatiblity disable
+    build flags.
+
+### Changed
+
+*   (flags) Flag serialization is now deterministic: this improves Bazel build
+    caching for tools that are affected by flag serialization.
+
+## 0.6.0 (2018-10-22)
+
+### Added
+
+*   Tempfile management APIs for tests: read/write/manage tempfiles for test
+    purposes easily and correctly. See TestCase.create_temp{file/dir} and the
+    corresponding commit for more info.
+
+## 0.5.0 (2018-09-17)
+
+### Added
+
+*   Flags enum support: flags.DEFINE_enum_class allows using an `Enum` derived
+    class to define the allowed values for a flag.
+
+## 0.4.1 (2018-08-28)
+
+### Fixed
+
+*   Flags no long allow spaces in their names
+
+### Changed
+
+*   XML test output is written at the end of all test execution.
+*   If the current user's username can't be gotten, fallback to uid, else fall
+    back to a generic 'unknown' string.
+
+## 0.4.0 (2018-08-14)
+
+### Added
+
+*   argparse integration: absl-registered flags can now be accessed via argparse
+    using absl.flags.argparse_flags: see that module for more information.
+*   TestCase.assertSameStructure now allows mixed set types.
+
+### Changed
+
+*   Test output now includes start/end markers for each test ran. This is to
+    help distinguish output from tests clearly.
+
+## 0.3.0 (2018-07-25)
+
+### Added
+
+*   `app.call_after_init`: Register functions to be called after app.run() is
+    called. Useful for program-wide initialization that library code may need.
+*   `logging.log_every_n_seconds`: like log_every_n, but based on elapsed time
+    between logging calls.
+*   `absltest.mock`: alias to unittest.mock (PY3) for better unittest drop-in
+    replacement. For PY2, it will be available if mock is importable.
+
+### Fixed
+
+*   `ABSLLogger.findCaller()`: allow stack_info arg and return value for PY2
+*   Make stopTest locking reentrant: this prevents deadlocks for test frameworks
+    that customize unittest.TextTestResult.stopTest.
+*   Make --helpfull work with unicode flag help strings.