NEWS.md
In lifecycle: Manage the Life Cycle of your Package Functions

lifecycle 1.0.4

Repeated calls to deprecate_soft() and deprecate_warn() are faster thanks to some internal refactoring (#177).
Switch from expr_deparse() to deparse(). This improves performance considerably and the cost of making some unusual function calls mildly less appealing (#167).

The with line is now an info bullet. The details lines are info bullets by default, unless the argument is named.
Indirect usages of deprecated features now mention the package that likely used the deprecated feature and recommends contacting the authors (#135).
Indirect usages of deprecate_warn() no longer warn repeatedly, even if always = TRUE (#135).
In tests, deprecate_soft() will only warn if the deprecated function is called directly from the package being tested, not one of its dependencies. This ensures that you only see the warning when it's your responsibility to do something about it (#134).
Soft deprecations now only warn every 8 hours in non-package code (#134).

You can now generate arbitrary text in a deprecation message by wrapping what or with in I() (#120).
deprecate_warn() gains an always = TRUE argument to force warnings to occur every time, not every 8 hours. This adds an extra step in between deprecate_warn() and deprecate_stop() (#124).
signal_stage() now supports with (#116).

deprecate_soft() now follows the verbosity option when called from the global environment (#113).
last_warnings() has been renamed to last_lifecycle_warnings() and last_warning() has been removed. This is for compatibility with the future rlang::last_warnings() function to be released in the next rlang version.

New vignettes:
vignette("stages") describes the lifecycle stages
vignette("manage") teaches you how to manage lifecycle changes in functions you use.
vignette("communicate") shows how to use lifecycle in functions that you write.
In deprecate_soft(), deprecate_warn(), and deprecate_stop():
You can deprecate an argument with foo(arg) instead of foo(arg =) (#78). This syntax is similar in spirit to the formal arguments of function definitions.
You can deprecate R6 methods by using class$method() (#54).
A character vector details is now converted into a bulleted list (#55).
Messages for non-prefix functions (like "x<-()" and "%>%()") look a little nicer (#95).
Manually printed warnings now omit the advice footer (#68).
Experimental signal_stage() can be used to signal that a function is experimental or superseded. These signals are not currently hooked up to any behaviour, but we'll add tools in a future release (#44).
lifecycle_cnd_data() has been removed; as far as I can tell it wasn't used by anyone.

Lifecycle warnings are now displayed once every 8 hours.
Added experimental signal_experimental() and signal_superseded() functions.
Added the "superseded" lifecycle stage to the documentation.
deprecate_stop() now mentions that function is defunct (#28).
New expect_deprecated() and expect_defunct() functions for testting lifecycle warnings and errors. expect_deprecated() automatically sets the lifecycle_verbosity option to "warning" to enforce warnings at each invokation rather than once per session.
New syntax "foo(arg = 'can\\'t be a baz')" to describe that specific inputs for an argument are deprecated (#30, @krlmlr).
New is_present() function to test whether the caller has supplied a deprecated() function.

Deprecated functions under the control of the developer now warn repeatedly in unit tests.
Deprecation warnings now record a backtrace. Call lifecycle::last_lifecycle_warnings() and lifecycle::last_warning() to print the warnings that occurred during the last command, along with their backtraces.
The naming scheme of signaller functions has been simplified:
signal_soft_deprecated() is now deprecate_soft().
warn_deprecated() is now deprecate_warn().
stop_defunct() is now deprecate_stop().
The signaller functions now take a version and two descriptors for the deprecated feature and its replacement (the latter is optional). The deprecation message is built from these components. You can pass a details argument to append additional information to the generated deprecation message.
Helpers from rlang's compat-lifecycle.R drop-in file are now exported in this package.