From ddd8ad1851be35b82c85039e3a92bbd2ddb1c6e5 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Tue, 10 Sep 2019 17:25:46 -0700
Subject: [PATCH 1/9] subscriber: rename Filter to EnvFilter

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 tracing-subscriber/Cargo.toml                |  2 +-
 tracing-subscriber/src/filter/env/mod.rs     | 60 ++++++++++----------
 tracing-subscriber/src/filter/mod.rs         |  8 +++
 tracing-subscriber/src/fmt/mod.rs            | 26 ++++-----
 tracing-subscriber/src/lib.rs                | 10 ++--
 tracing-subscriber/src/reload.rs             | 12 ++--
 tracing-subscriber/tests/field_filter.rs     |  8 +--
 tracing-subscriber/tests/filter.rs           | 12 ++--
 tracing-subscriber/tests/same_len_filters.rs |  8 +--
 9 files changed, 78 insertions(+), 68 deletions(-)

diff --git a/tracing-subscriber/Cargo.toml b/tracing-subscriber/Cargo.toml
index e9542e75ce..2b2c0ebd7e 100644
--- a/tracing-subscriber/Cargo.toml
+++ b/tracing-subscriber/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "tracing-subscriber"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Eliza Weisman <eliza@buoyant.io>", "Tokio Contributors <team@tokio.rs>"]
 edition = "2018"
 license = "MIT"
diff --git a/tracing-subscriber/src/filter/env/mod.rs b/tracing-subscriber/src/filter/env/mod.rs
index 107926f0fd..5133e7bc1f 100644
--- a/tracing-subscriber/src/filter/env/mod.rs
+++ b/tracing-subscriber/src/filter/env/mod.rs
@@ -30,7 +30,7 @@ use tracing_core::{
 /// directives.
 // TODO(eliza): document filter directive syntax?
 #[derive(Debug)]
-pub struct Filter {
+pub struct EnvFilter {
     // TODO: eventually, this should be exposed by the registry.
     scope: thread::Local<Vec<LevelFilter>>,
 
@@ -48,7 +48,7 @@ type FilterVec<T> = smallvec::SmallVec<[T; 8]>;
 #[cfg(not(feature = "smallvec"))]
 type FilterVec<T> = Vec<T>;
 
-/// Indicates that an error occurred while parsing a `Filter` from an
+/// Indicates that an error occurred while parsing a `EnvFilter` from an
 /// environment variable.
 #[derive(Debug)]
 pub struct FromEnvError {
@@ -61,27 +61,27 @@ enum ErrorKind {
     Env(env::VarError),
 }
 
-impl Filter {
-    /// The default environment variable used by [`Filter::from_default_env`]
-    /// and [`Filter::try_from_default_env`].
+impl EnvFilter {
+    /// The default environment variable used by [`EnvFilter::from_default_env`]
+    /// and [`EnvFilter::try_from_default_env`].
     ///
-    /// [`Filter::from_default_env`]: #method.from_default_env
-    /// [`Filter::try_from_default_env`]: #method.try_from_default_env
+    /// [`EnvFilter::from_default_env`]: #method.from_default_env
+    /// [`EnvFilter::try_from_default_env`]: #method.try_from_default_env
     pub const DEFAULT_ENV: &'static str = "RUST_LOG";
 
-    /// Returns a new `Filter` from the value of the `RUST_LOG` environment
+    /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment
     /// variable, ignoring any invalid filter directives.
     pub fn from_default_env() -> Self {
         Self::from_env(Self::DEFAULT_ENV)
     }
 
-    /// Returns a new `Filter` from the value of the given environment
+    /// Returns a new `EnvFilter` from the value of the given environment
     /// variable, ignoring any invalid filter directives.
     pub fn from_env<A: AsRef<str>>(env: A) -> Self {
         env::var(env.as_ref()).map(Self::new).unwrap_or_default()
     }
 
-    /// Returns a new `Filter` from the directives in the given string,
+    /// Returns a new `EnvFilter` from the directives in the given string,
     /// ignoring any that are invalid.
     pub fn new<S: AsRef<str>>(dirs: S) -> Self {
         let directives = dirs.as_ref().split(',').filter_map(|s| match s.parse() {
@@ -94,7 +94,7 @@ impl Filter {
         Self::from_directives(directives)
     }
 
-    /// Returns a new `Filter` from the directives in the given string,
+    /// Returns a new `EnvFilter` from the directives in the given string,
     /// or an error if any are invalid.
     pub fn try_new<S: AsRef<str>>(dirs: S) -> Result<Self, ParseError> {
         let directives = dirs
@@ -105,21 +105,21 @@ impl Filter {
         Ok(Self::from_directives(directives))
     }
 
-    /// Returns a new `Filter` from the value of the `RUST_LOG` environment
+    /// Returns a new `EnvFilter` from the value of the `RUST_LOG` environment
     /// variable, or an error if the environment variable contains any invalid
     /// filter directives.
     pub fn try_from_default_env() -> Result<Self, FromEnvError> {
         Self::try_from_env(Self::DEFAULT_ENV)
     }
 
-    /// Returns a new `Filter` from the value of the given environment
+    /// Returns a new `EnvFilter` from the value of the given environment
     /// variable, or an error if the environment variable is unset or contains
     /// any invalid filter directives.
     pub fn try_from_env<A: AsRef<str>>(env: A) -> Result<Self, FromEnvError> {
         env::var(env.as_ref())?.parse().map_err(Into::into)
     }
 
-    /// Add a filtering directive to this `Filter`.
+    /// Add a filtering directive to this `EnvFilter`.
     ///
     /// The added directive will be used in addition to any previously set
     /// directives, either added using this method or provided when the filter
@@ -137,17 +137,17 @@ impl Filter {
     ///
     /// # Examples
     /// ```rust
-    /// use tracing_subscriber::filter::{Filter, LevelFilter};
+    /// use tracing_subscriber::filter::{EnvFilter, LevelFilter};
     /// # fn main() {
-    /// let mut filter = Filter::from_default_env()
+    /// let mut filter = EnvFilter::from_default_env()
     ///     .add_directive(LevelFilter::INFO.into());
     /// # }
     /// ```
     /// ```rust
-    /// use tracing_subscriber::filter::{Filter, Directive};
+    /// use tracing_subscriber::filter::{EnvFilter, Directive};
     ///
     /// # fn try_mk_filter() -> Result<(), Box<dyn ::std::error::Error>> {
-    /// let mut filter = Filter::try_from_default_env()?
+    /// let mut filter = EnvFilter::try_from_default_env()?
     ///     .add_directive("my_crate::module=trace".parse()?)
     ///     .add_directive("my_crate::my_other_module::something=info".parse()?);
     /// # Ok(())
@@ -193,7 +193,7 @@ impl Filter {
     }
 }
 
-impl<S: Subscriber> Layer<S> for Filter {
+impl<S: Subscriber> Layer<S> for EnvFilter {
     fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest {
         if metadata.is_span() {
             // If this metadata describes a span, first, check if there is a
@@ -271,7 +271,7 @@ impl<S: Subscriber> Layer<S> for Filter {
     }
 }
 
-impl FromStr for Filter {
+impl FromStr for EnvFilter {
     type Err = ParseError;
 
     fn from_str(spec: &str) -> Result<Self, Self::Err> {
@@ -279,7 +279,7 @@ impl FromStr for Filter {
     }
 }
 
-impl<S> From<S> for Filter
+impl<S> From<S> for EnvFilter
 where
     S: AsRef<str>,
 {
@@ -288,13 +288,13 @@ where
     }
 }
 
-impl Default for Filter {
+impl Default for EnvFilter {
     fn default() -> Self {
         Self::from_directives(std::iter::empty())
     }
 }
 
-impl fmt::Display for Filter {
+impl fmt::Display for EnvFilter {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut statics = self.statics.iter();
         let wrote_statics = if let Some(next) = statics.next() {
@@ -401,7 +401,7 @@ mod tests {
 
     #[test]
     fn callsite_enabled_no_span_directive() {
-        let filter = Filter::new("app=debug").with_subscriber(NoSubscriber);
+        let filter = EnvFilter::new("app=debug").with_subscriber(NoSubscriber);
         static META: &'static Metadata<'static> = &Metadata::new(
             "mySpan",
             "app",
@@ -419,7 +419,7 @@ mod tests {
 
     #[test]
     fn callsite_off() {
-        let filter = Filter::new("app=off").with_subscriber(NoSubscriber);
+        let filter = EnvFilter::new("app=off").with_subscriber(NoSubscriber);
         static META: &'static Metadata<'static> = &Metadata::new(
             "mySpan",
             "app",
@@ -437,7 +437,7 @@ mod tests {
 
     #[test]
     fn callsite_enabled_includes_span_directive() {
-        let filter = Filter::new("app[mySpan]=debug").with_subscriber(NoSubscriber);
+        let filter = EnvFilter::new("app[mySpan]=debug").with_subscriber(NoSubscriber);
         static META: &'static Metadata<'static> = &Metadata::new(
             "mySpan",
             "app",
@@ -456,7 +456,7 @@ mod tests {
     #[test]
     fn callsite_enabled_includes_span_directive_field() {
         let filter =
-            Filter::new("app[mySpan{field=\"value\"}]=debug").with_subscriber(NoSubscriber);
+            EnvFilter::new("app[mySpan{field=\"value\"}]=debug").with_subscriber(NoSubscriber);
         static META: &'static Metadata<'static> = &Metadata::new(
             "mySpan",
             "app",
@@ -474,7 +474,7 @@ mod tests {
 
     #[test]
     fn callsite_enabled_includes_span_directive_multiple_fields() {
-        let filter = Filter::new("app[mySpan{field=\"value\",field2=2}]=debug")
+        let filter = EnvFilter::new("app[mySpan{field=\"value\",field2=2}]=debug")
             .with_subscriber(NoSubscriber);
         static META: &'static Metadata<'static> = &Metadata::new(
             "mySpan",
@@ -493,11 +493,11 @@ mod tests {
 
     #[test]
     fn roundtrip() {
-        let f1: Filter =
+        let f1: EnvFilter =
             "[span1{foo=1}]=error,[span2{bar=2 baz=false}],crate2[{quux=\"quuux\"}]=debug"
                 .parse()
                 .unwrap();
-        let f2: Filter = format!("{}", f1).parse().unwrap();
+        let f2: EnvFilter = format!("{}", f1).parse().unwrap();
         assert_eq!(f1.statics, f2.statics);
         assert_eq!(f1.dynamics, f2.dynamics);
     }
diff --git a/tracing-subscriber/src/filter/mod.rs b/tracing-subscriber/src/filter/mod.rs
index 99cbde1274..21c38fe415 100644
--- a/tracing-subscriber/src/filter/mod.rs
+++ b/tracing-subscriber/src/filter/mod.rs
@@ -10,3 +10,11 @@ pub use self::level::{LevelFilter, ParseError as LevelParseError};
 
 #[cfg(feature = "filter")]
 pub use self::env::*;
+
+/// A `Layer` which filters spans and events based on a set of filter
+/// directives.
+///
+/// **Note**: renamed to `EnvFilter` in 0.1.2; use that instead.
+#[cfg(feature = "filter")]
+#[deprecated(since = "0.1.2", note = "renamed to `EnvFilter`")]
+pub type Filter = EnvFilter;
diff --git a/tracing-subscriber/src/fmt/mod.rs b/tracing-subscriber/src/fmt/mod.rs
index 9d218b14a6..1026146265 100644
--- a/tracing-subscriber/src/fmt/mod.rs
+++ b/tracing-subscriber/src/fmt/mod.rs
@@ -384,7 +384,7 @@ where
 }
 
 #[cfg(feature = "filter")]
-impl<N, E, W> Builder<N, E, crate::Filter, W>
+impl<N, E, W> Builder<N, E, crate::EnvFilter, W>
 where
     Formatter<N, E, W>: tracing_core::Subscriber + 'static,
 {
@@ -392,7 +392,7 @@ where
     /// runtime.
     pub fn with_filter_reloading(
         self,
-    ) -> Builder<N, E, crate::reload::Layer<crate::Filter, Formatter<N, E, W>>, W> {
+    ) -> Builder<N, E, crate::reload::Layer<crate::EnvFilter, Formatter<N, E, W>>, W> {
         let (filter, _) = crate::reload::Layer::new(self.filter);
         Builder {
             new_visitor: self.new_visitor,
@@ -405,13 +405,13 @@ where
 }
 
 #[cfg(feature = "filter")]
-impl<N, E, W> Builder<N, E, crate::reload::Layer<crate::Filter, Formatter<N, E, W>>, W>
+impl<N, E, W> Builder<N, E, crate::reload::Layer<crate::EnvFilter, Formatter<N, E, W>>, W>
 where
     Formatter<N, E, W>: tracing_core::Subscriber + 'static,
 {
     /// Returns a `Handle` that may be used to reload the constructed subscriber's
     /// filter.
-    pub fn reload_handle(&self) -> crate::reload::Handle<crate::Filter, Formatter<N, E, W>> {
+    pub fn reload_handle(&self) -> crate::reload::Handle<crate::EnvFilter, Formatter<N, E, W>> {
         self.filter.handle()
     }
 }
@@ -432,7 +432,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
         }
     }
 
-    /// Sets the [`Filter`] that the subscriber will use to determine if
+    /// Sets the [`EnvFilter`] that the subscriber will use to determine if
     /// a span or event is enabled.
     ///
     /// Note that this method requires the "filter" feature flag to be enabled.
@@ -445,10 +445,10 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// Setting a filter based on the value of the `RUST_LOG` environment
     /// variable:
     /// ```rust
-    /// use tracing_subscriber::{FmtSubscriber, Filter};
+    /// use tracing_subscriber::{FmtSubscriber, EnvFilter};
     ///
     /// let subscriber = FmtSubscriber::builder()
-    ///     .with_filter(Filter::from_default_env())
+    ///     .with_filter(EnvFilter::from_default_env())
     ///     .finish();
     /// ```
     ///
@@ -467,11 +467,11 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// ```rust
     /// use tracing_subscriber::{
     ///     FmtSubscriber,
-    ///     filter::{Filter, LevelFilter},
+    ///     filter::{EnvFilter, LevelFilter},
     /// };
     ///
     /// # fn filter() -> Result<(), Box<dyn std::error::Error>> {
-    /// let filter = Filter::try_from_env("MY_CUSTOM_FILTER_ENV_VAR")?
+    /// let filter = EnvFilter::try_from_env("MY_CUSTOM_FILTER_ENV_VAR")?
     ///     // Set the base level when not matched by other directives to WARN.
     ///     .add_directive(LevelFilter::WARN.into())
     ///     // Set the max level for `my_crate::my_mod` to DEBUG, overriding
@@ -483,10 +483,10 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     ///     .finish();
     /// # Ok(())}
     /// ```
-    /// [`Filter`]: ../filter/struct.Filter.html
+    /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_max_level`]: #method.with_max_level
     #[cfg(feature = "filter")]
-    pub fn with_filter(self, filter: impl Into<crate::Filter>) -> Builder<N, E, crate::Filter, W>
+    pub fn with_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
     where
         Formatter<N, E, W>: tracing_core::Subscriber + 'static,
     {
@@ -503,7 +503,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// Sets the maximum [verbosity level] that will be enabled by the
     /// subscriber.
     ///
-    /// If the max level has already been set, or a [`Filter`] was added by
+    /// If the max level has already been set, or a [`EnvFilter`] was added by
     /// [`with_filter`], this replaces that configuration with the new
     /// maximum level.
     ///
@@ -530,7 +530,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     ///     .finish();
     /// ```
     /// [verbosity level]: https://docs.rs/tracing-core/0.1.5/tracing_core/struct.Level.html
-    /// [`Filter`]: ../filter/struct.Filter.html
+    /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_filter`]: #method.with_filter
     pub fn with_max_level(self, filter: impl Into<LevelFilter>) -> Builder<N, E, LevelFilter, W> {
         let filter = filter.into();
diff --git a/tracing-subscriber/src/lib.rs b/tracing-subscriber/src/lib.rs
index 22b423142a..485c1c2204 100644
--- a/tracing-subscriber/src/lib.rs
+++ b/tracing-subscriber/src/lib.rs
@@ -12,7 +12,7 @@
 //!
 //! ## Feature Flags
 //!
-//! - `filter`: Enables the [`Filter`] type, which implements filtering similar
+//! - `filter`: Enables the [`EnvFilter`] type, which implements filtering similar
 //!   to the [`env_logger` crate]. Enabled by default.
 //! - `fmt`: Enables the [`fmt`] module, which provides a subscriber
 //!   implementation for printing formatted representations of trace events.
@@ -25,12 +25,12 @@
 //!   macros in the `fmt` subscriber. On by default.
 //! - [`chrono`]: Enables human-readable time formatting in the `fmt` subscriber.
 //!   Enabled by default.
-//! - [`smallvec`]: Causes the `Filter` type to use the `smallvec` crate (rather
+//! - [`smallvec`]: Causes the `EnvFilter` type to use the `smallvec` crate (rather
 //!   than `Vec`) as a performance optimization. Enabled by default.
 //!
 //! [`tracing`]: https://docs.rs/tracing/latest/tracing/
 //! [`Subscriber`]: https://docs.rs/tracing-core/latest/tracing_core/subscriber/trait.Subscriber.html
-//! [`Filter`]: filter/struct.Filter.html
+//! [`EnvFilter`]: filter/struct.EnvFilter.html
 //! [`fmt`]: fmt/index.html
 //! [`tracing-log`]: https://crates.io/crates/tracing-log
 //! [`smallvec`]: https://crates.io/crates/smallvec
@@ -97,7 +97,9 @@ pub mod reload;
 pub(crate) mod thread;
 
 #[cfg(feature = "filter")]
-pub use filter::Filter;
+#[allow(deprecated)]
+pub use filter::{Filter, EnvFilter};
+
 pub use layer::Layer;
 
 #[cfg(feature = "fmt")]
diff --git a/tracing-subscriber/src/reload.rs b/tracing-subscriber/src/reload.rs
index 7546709440..82d81ee7d7 100644
--- a/tracing-subscriber/src/reload.rs
+++ b/tracing-subscriber/src/reload.rs
@@ -248,19 +248,19 @@ mod test {
         static FILTER1_CALLS: AtomicUsize = AtomicUsize::new(0);
         static FILTER2_CALLS: AtomicUsize = AtomicUsize::new(0);
 
-        enum Filter {
+        enum EnvFilter {
             One,
             Two,
         }
-        impl<S: Subscriber> crate::Layer<S> for Filter {
+        impl<S: Subscriber> crate::Layer<S> for EnvFilter {
             fn register_callsite(&self, _: &Metadata<'_>) -> Interest {
                 Interest::sometimes()
             }
 
             fn enabled(&self, _: &Metadata<'_>, _: layer::Context<'_, S>) -> bool {
                 match self {
-                    Filter::One => FILTER1_CALLS.fetch_add(1, Ordering::Relaxed),
-                    Filter::Two => FILTER2_CALLS.fetch_add(1, Ordering::Relaxed),
+                    EnvFilter::One => FILTER1_CALLS.fetch_add(1, Ordering::Relaxed),
+                    EnvFilter::Two => FILTER2_CALLS.fetch_add(1, Ordering::Relaxed),
                 };
                 true
             }
@@ -269,7 +269,7 @@ mod test {
             tracing::trace!("my event");
         }
 
-        let (layer, handle) = Layer::new(Filter::One);
+        let (layer, handle) = Layer::new(EnvFilter::One);
 
         let subscriber =
             tracing_core::dispatcher::Dispatch::new(crate::layer::tests::NopSubscriber.with(layer));
@@ -283,7 +283,7 @@ mod test {
             assert_eq!(FILTER1_CALLS.load(Ordering::Relaxed), 1);
             assert_eq!(FILTER2_CALLS.load(Ordering::Relaxed), 0);
 
-            handle.reload(Filter::Two).expect("should reload");
+            handle.reload(EnvFilter::Two).expect("should reload");
 
             event();
 
diff --git a/tracing-subscriber/tests/field_filter.rs b/tracing-subscriber/tests/field_filter.rs
index 94b2af2333..7c39441739 100644
--- a/tracing-subscriber/tests/field_filter.rs
+++ b/tracing-subscriber/tests/field_filter.rs
@@ -1,11 +1,11 @@
 mod support;
 use self::support::*;
 use tracing::{self, subscriber::with_default, Level};
-use tracing_subscriber::{filter::Filter, prelude::*};
+use tracing_subscriber::{filter::EnvFilter, prelude::*};
 
 #[test]
 fn field_filter_events() {
-    let filter: Filter = "[{thing}]=debug".parse().expect("filter should parse");
+    let filter: EnvFilter = "[{thing}]=debug".parse().expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
         .event(
             event::mock()
@@ -34,7 +34,7 @@ fn field_filter_events() {
 
 #[test]
 fn field_filter_spans() {
-    let filter: Filter = "[{enabled=true}]=debug"
+    let filter: EnvFilter = "[{enabled=true}]=debug"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
@@ -77,7 +77,7 @@ fn field_filter_spans() {
 
 #[test]
 fn record_after_created() {
-    let filter: Filter = "[{enabled=true}]=debug"
+    let filter: EnvFilter = "[{enabled=true}]=debug"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
diff --git a/tracing-subscriber/tests/filter.rs b/tracing-subscriber/tests/filter.rs
index 385cba22c5..4f52a7fd94 100644
--- a/tracing-subscriber/tests/filter.rs
+++ b/tracing-subscriber/tests/filter.rs
@@ -1,11 +1,11 @@
 mod support;
 use self::support::*;
 use tracing::{self, subscriber::with_default, Level};
-use tracing_subscriber::{filter::Filter, prelude::*};
+use tracing_subscriber::{filter::EnvFilter, prelude::*};
 
 #[test]
 fn level_filter_event() {
-    let filter: Filter = "info".parse().expect("filter should parse");
+    let filter: EnvFilter = "info".parse().expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
         .event(event::mock().at_level(Level::INFO))
         .event(event::mock().at_level(Level::WARN))
@@ -27,7 +27,7 @@ fn level_filter_event() {
 
 #[test]
 fn same_name_spans() {
-    let filter: Filter = "[foo{bar}]=trace,[foo{baz}]=trace"
+    let filter: EnvFilter = "[foo{bar}]=trace,[foo{baz}]=trace"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
@@ -56,7 +56,7 @@ fn same_name_spans() {
 
 #[test]
 fn level_filter_event_with_target() {
-    let filter: Filter = "info,stuff=debug".parse().expect("filter should parse");
+    let filter: EnvFilter = "info,stuff=debug".parse().expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
         .event(event::mock().at_level(Level::INFO))
         .event(event::mock().at_level(Level::DEBUG).with_target("stuff"))
@@ -83,7 +83,7 @@ fn level_filter_event_with_target() {
 
 #[test]
 fn span_name_filter_is_dynamic() {
-    let filter: Filter = "info,[cool_span]=debug"
+    let filter: EnvFilter = "info,[cool_span]=debug"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
@@ -129,7 +129,7 @@ fn span_name_filter_is_dynamic() {
 
 #[test]
 fn field_filter_events() {
-    let filter: Filter = "[{thing}]=debug".parse().expect("filter should parse");
+    let filter: EnvFilter = "[{thing}]=debug".parse().expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
         .event(
             event::mock()
diff --git a/tracing-subscriber/tests/same_len_filters.rs b/tracing-subscriber/tests/same_len_filters.rs
index bb0de62ff1..5b85ac7717 100644
--- a/tracing-subscriber/tests/same_len_filters.rs
+++ b/tracing-subscriber/tests/same_len_filters.rs
@@ -4,11 +4,11 @@
 mod support;
 use self::support::*;
 use tracing::{self, subscriber::with_default, Level};
-use tracing_subscriber::{filter::Filter, prelude::*};
+use tracing_subscriber::{filter::EnvFilter, prelude::*};
 
 #[test]
 fn same_length_targets() {
-    let filter: Filter = "foo=trace,bar=trace".parse().expect("filter should parse");
+    let filter: EnvFilter = "foo=trace,bar=trace".parse().expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
         .event(event::mock().at_level(Level::TRACE))
         .event(event::mock().at_level(Level::TRACE))
@@ -26,7 +26,7 @@ fn same_length_targets() {
 
 #[test]
 fn same_num_fields_event() {
-    let filter: Filter = "[{foo}]=trace,[{bar}]=trace"
+    let filter: EnvFilter = "[{foo}]=trace,[{bar}]=trace"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()
@@ -53,7 +53,7 @@ fn same_num_fields_event() {
 
 #[test]
 fn same_num_fields_and_name_len() {
-    let filter: Filter = "[foo{bar=1}]=trace,[baz{boz=1}]=trace"
+    let filter: EnvFilter = "[foo{bar=1}]=trace,[baz{boz=1}]=trace"
         .parse()
         .expect("filter should parse");
     let (subscriber, finished) = subscriber::mock()

From 686c1eb7746499a66c191b9f67ffe497dc9f2268 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Tue, 10 Sep 2019 17:26:21 -0700
Subject: [PATCH 2/9] chore: update examples

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 examples/examples/futures-proxy-server.rs | 4 ++--
 examples/examples/subscriber-filter.rs    | 4 ++--
 examples/examples/tower-h2-client.rs      | 4 ++--
 examples/examples/tower-h2-server.rs      | 4 ++--
 examples/examples/tower-load.rs           | 4 ++--
 nightly-examples/examples/echo.rs         | 4 ++--
 nightly-examples/examples/proxy_server.rs | 4 ++--
 7 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/examples/examples/futures-proxy-server.rs b/examples/examples/futures-proxy-server.rs
index 9ed88ea353..b655377354 100644
--- a/examples/examples/futures-proxy-server.rs
+++ b/examples/examples/futures-proxy-server.rs
@@ -17,10 +17,10 @@ use tokio::net::{TcpListener, TcpStream};
 use tokio::prelude::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    use tracing_subscriber::{fmt, Filter};
+    use tracing_subscriber::{fmt, EnvFilter};
 
     let subscriber = fmt::Subscriber::builder()
-        .with_filter(Filter::from_default_env())
+        .with_filter(EnvFilter::from_default_env())
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 
diff --git a/examples/examples/subscriber-filter.rs b/examples/examples/subscriber-filter.rs
index 67fccb884a..66b274af94 100644
--- a/examples/examples/subscriber-filter.rs
+++ b/examples/examples/subscriber-filter.rs
@@ -3,10 +3,10 @@
 mod yak_shave;
 
 fn main() {
-    use tracing_subscriber::{fmt, Filter};
+    use tracing_subscriber::{fmt, EnvFilter};
 
     let subscriber = fmt::Subscriber::builder()
-        .with_filter(Filter::from_default_env())
+        .with_filter(EnvFilter::from_default_env())
         .finish();
 
     tracing::subscriber::with_default(subscriber, || {
diff --git a/examples/examples/tower-h2-client.rs b/examples/examples/tower-h2-client.rs
index a2c728f3d2..636979fcf4 100644
--- a/examples/examples/tower-h2-client.rs
+++ b/examples/examples/tower-h2-client.rs
@@ -18,10 +18,10 @@ use tracing_tower::InstrumentableService;
 pub struct Conn(SocketAddr);
 
 fn main() {
-    use tracing_subscriber::filter::Filter;
+    use tracing_subscriber::filter::EnvFilter;
     // Set the default subscriber to record all traces emitted by this example
     // and by the `tracing_tower` library's helpers.
-    let filter = Filter::from_default_env()
+    let filter = EnvFilter::from_default_env()
         .add_directive("tower_h2_client=trace".parse().unwrap())
         .add_directive("tracing_tower=trace".parse().unwrap());
     let subscriber = tracing_subscriber::FmtSubscriber::builder()
diff --git a/examples/examples/tower-h2-server.rs b/examples/examples/tower-h2-server.rs
index 8df087ddb7..0750c4f30b 100644
--- a/examples/examples/tower-h2-server.rs
+++ b/examples/examples/tower-h2-server.rs
@@ -95,8 +95,8 @@ impl tower_service::Service<()> for NewSvc {
 fn main() {
     // Set the default subscriber to record all traces emitted by this example
     // and by the `tracing_tower` library's helpers.
-    use tracing_subscriber::filter::Filter;
-    let filter = Filter::from_default_env()
+    use tracing_subscriber::filter::EnvFilter;
+    let filter = EnvFilter::from_default_env()
         .add_directive("tower_h2_server=trace".parse().unwrap())
         .add_directive("tracing_tower=trace".parse().unwrap());
     let subscriber = tracing_subscriber::FmtSubscriber::builder()
diff --git a/examples/examples/tower-load.rs b/examples/examples/tower-load.rs
index 7273d27d33..e29d3ad7ab 100644
--- a/examples/examples/tower-load.rs
+++ b/examples/examples/tower-load.rs
@@ -224,7 +224,7 @@ impl Service<()> for MakeSvc {
 }
 
 struct AdminSvc<S> {
-    handle: tracing_subscriber::reload::Handle<tracing_subscriber::filter::Filter, S>,
+    handle: tracing_subscriber::reload::Handle<tracing_subscriber::filter::EnvFilter, S>,
 }
 
 impl<S> Clone for AdminSvc<S> {
@@ -296,7 +296,7 @@ where
         let body = str::from_utf8(&bytes.as_ref()).map_err(|e| format!("{}", e))?;
         tracing::trace!(request.body = ?body);
         let new_filter = body
-            .parse::<tracing_subscriber::filter::Filter>()
+            .parse::<tracing_subscriber::filter::EnvFilter>()
             .map_err(|e| format!("{}", e))?;
         self.handle.reload(new_filter).map_err(|e| format!("{}", e))
     }
diff --git a/nightly-examples/examples/echo.rs b/nightly-examples/examples/echo.rs
index e4d0b00523..d4afba45fd 100644
--- a/nightly-examples/examples/echo.rs
+++ b/nightly-examples/examples/echo.rs
@@ -37,10 +37,10 @@ use tracing_futures::Instrument;
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error>> {
-    use tracing_subscriber::{Filter, FmtSubscriber};
+    use tracing_subscriber::{EnvFilter, FmtSubscriber};
 
     let subscriber = FmtSubscriber::builder()
-        .with_filter(Filter::from_default_env().add_directive("echo=trace".parse()?))
+        .with_filter(EnvFilter::from_default_env().add_directive("echo=trace".parse()?))
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 
diff --git a/nightly-examples/examples/proxy_server.rs b/nightly-examples/examples/proxy_server.rs
index baa3289861..ed6270624b 100644
--- a/nightly-examples/examples/proxy_server.rs
+++ b/nightly-examples/examples/proxy_server.rs
@@ -86,10 +86,10 @@ async fn transfer(
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    use tracing_subscriber::{Filter, FmtSubscriber};
+    use tracing_subscriber::{EnvFilter, FmtSubscriber};
 
     let subscriber = FmtSubscriber::builder()
-        .with_filter(Filter::from_default_env().add_directive("proxy_server=trace".parse()?))
+        .with_filter(EnvFilter::from_default_env().add_directive("proxy_server=trace".parse()?))
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 

From f284d8e6dfc2ff5ba07c0e4358ece37e85607a5f Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 10:30:06 -0700
Subject: [PATCH 3/9] subscriber: rename `with_filter`

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 tracing-subscriber/src/fmt/mod.rs | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/tracing-subscriber/src/fmt/mod.rs b/tracing-subscriber/src/fmt/mod.rs
index 1026146265..5d18cfb9bb 100644
--- a/tracing-subscriber/src/fmt/mod.rs
+++ b/tracing-subscriber/src/fmt/mod.rs
@@ -486,7 +486,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_max_level`]: #method.with_max_level
     #[cfg(feature = "filter")]
-    pub fn with_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
+    pub fn with_env_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
     where
         Formatter<N, E, W>: tracing_core::Subscriber + 'static,
     {
@@ -500,6 +500,24 @@ impl<N, E, F, W> Builder<N, E, F, W> {
         }
     }
 
+    /// Sets the [`EnvFilter`] that the subscriber will use to determine if
+    /// a span or event is enabled.
+    ///
+    /// **Note**: this method was renamed to [`with_env_filter`] in version
+    /// 0.1.2. This method just wraps a call to `with_env_filter`, and will be
+    /// removed in version 0.2.
+    ///
+    /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
+    /// [`with_env_filter`]: #method.with_env_filter
+    #[cfg(feature = "filter")]
+    #[deprecated(since = "0.1.2", note = "renamed to `with_env_filter`")]
+    pub fn with_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
+    where
+        Formatter<N, E, W>: tracing_core::Subscriber + 'static,
+    {
+        self.with_env_filter(filter)
+    }
+
     /// Sets the maximum [verbosity level] that will be enabled by the
     /// subscriber.
     ///

From e9fbe3093424c093cb69aaf87fc1977ac6dc129c Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 10:31:12 -0700
Subject: [PATCH 4/9] update examples

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 examples/examples/attrs-args.rs           | 2 +-
 examples/examples/attrs-basic.rs          | 2 +-
 examples/examples/futures-proxy-server.rs | 2 +-
 examples/examples/subscriber-filter.rs    | 2 +-
 examples/examples/tower-h2-client.rs      | 2 +-
 examples/examples/tower-h2-server.rs      | 2 +-
 examples/examples/tower-load.rs           | 4 ++--
 nightly-examples/examples/async_fn.rs     | 2 +-
 nightly-examples/examples/echo.rs         | 2 +-
 nightly-examples/examples/proxy_server.rs | 2 +-
 tracing-subscriber/src/fmt/mod.rs         | 6 +++---
 11 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/examples/examples/attrs-args.rs b/examples/examples/attrs-args.rs
index 365f740736..08a8953fe8 100644
--- a/examples/examples/attrs-args.rs
+++ b/examples/examples/attrs-args.rs
@@ -29,7 +29,7 @@ fn fibonacci_seq(to: u64) -> Vec<u64> {
 fn main() {
     use tracing_subscriber::fmt;
     let subscriber = fmt::Subscriber::builder()
-        .with_filter("attrs_args=trace")
+        .with_env_filter("attrs_args=trace")
         .finish();
 
     tracing::subscriber::with_default(subscriber, || {
diff --git a/examples/examples/attrs-basic.rs b/examples/examples/attrs-basic.rs
index efbdaf65e6..bb6dd777d0 100644
--- a/examples/examples/attrs-basic.rs
+++ b/examples/examples/attrs-basic.rs
@@ -12,7 +12,7 @@ fn suggest_band() -> String {
 
 fn main() {
     let subscriber = tracing_subscriber::fmt::Subscriber::builder()
-        .with_filter("attrs_basic=trace")
+        .with_env_filter("attrs_basic=trace")
         .finish();
     tracing::subscriber::with_default(subscriber, || {
         let num_recs = 1;
diff --git a/examples/examples/futures-proxy-server.rs b/examples/examples/futures-proxy-server.rs
index b655377354..763dfdf870 100644
--- a/examples/examples/futures-proxy-server.rs
+++ b/examples/examples/futures-proxy-server.rs
@@ -20,7 +20,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     use tracing_subscriber::{fmt, EnvFilter};
 
     let subscriber = fmt::Subscriber::builder()
-        .with_filter(EnvFilter::from_default_env())
+        .with_env_filter(EnvFilter::from_default_env())
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 
diff --git a/examples/examples/subscriber-filter.rs b/examples/examples/subscriber-filter.rs
index 66b274af94..459b76b67b 100644
--- a/examples/examples/subscriber-filter.rs
+++ b/examples/examples/subscriber-filter.rs
@@ -6,7 +6,7 @@ fn main() {
     use tracing_subscriber::{fmt, EnvFilter};
 
     let subscriber = fmt::Subscriber::builder()
-        .with_filter(EnvFilter::from_default_env())
+        .with_env_filter(EnvFilter::from_default_env())
         .finish();
 
     tracing::subscriber::with_default(subscriber, || {
diff --git a/examples/examples/tower-h2-client.rs b/examples/examples/tower-h2-client.rs
index 636979fcf4..78e9c5460a 100644
--- a/examples/examples/tower-h2-client.rs
+++ b/examples/examples/tower-h2-client.rs
@@ -25,7 +25,7 @@ fn main() {
         .add_directive("tower_h2_client=trace".parse().unwrap())
         .add_directive("tracing_tower=trace".parse().unwrap());
     let subscriber = tracing_subscriber::FmtSubscriber::builder()
-        .with_filter(filter)
+        .with_env_filter(filter)
         .finish();
     let _ = tracing::subscriber::set_global_default(subscriber);
 
diff --git a/examples/examples/tower-h2-server.rs b/examples/examples/tower-h2-server.rs
index 0750c4f30b..508dbc9140 100644
--- a/examples/examples/tower-h2-server.rs
+++ b/examples/examples/tower-h2-server.rs
@@ -100,7 +100,7 @@ fn main() {
         .add_directive("tower_h2_server=trace".parse().unwrap())
         .add_directive("tracing_tower=trace".parse().unwrap());
     let subscriber = tracing_subscriber::FmtSubscriber::builder()
-        .with_filter(filter)
+        .with_env_filter(filter)
         .finish();
     let _ = tracing::subscriber::set_global_default(subscriber);
 
diff --git a/examples/examples/tower-load.rs b/examples/examples/tower-load.rs
index e29d3ad7ab..815b9e9093 100644
--- a/examples/examples/tower-load.rs
+++ b/examples/examples/tower-load.rs
@@ -36,8 +36,8 @@ use tracing_subscriber::FmtSubscriber;
 
 fn main() {
     let builder = FmtSubscriber::builder()
-        .with_filter("info,tower_load=debug")
-        .with_filter_reloading();
+        .with_env_filter("info,tower_load=debug")
+        .with_env_filter_reloading();
     let handle = builder.reload_handle();
 
     let _ = tracing::subscriber::set_global_default(builder.finish());
diff --git a/nightly-examples/examples/async_fn.rs b/nightly-examples/examples/async_fn.rs
index e957680496..7c67f3a3a5 100644
--- a/nightly-examples/examples/async_fn.rs
+++ b/nightly-examples/examples/async_fn.rs
@@ -44,7 +44,7 @@ pub async fn main() -> Result<(), Box<dyn Error>> {
     let addr = "127.0.0.1:6142".parse()?;
 
     let subscriber = tracing_subscriber::fmt::Subscriber::builder()
-        .with_filter("async_fn=trace")
+        .with_env_filter("async_fn=trace")
         .finish();
     tracing::subscriber::set_global_default(subscriber).unwrap();
 
diff --git a/nightly-examples/examples/echo.rs b/nightly-examples/examples/echo.rs
index d4afba45fd..f284845168 100644
--- a/nightly-examples/examples/echo.rs
+++ b/nightly-examples/examples/echo.rs
@@ -40,7 +40,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     use tracing_subscriber::{EnvFilter, FmtSubscriber};
 
     let subscriber = FmtSubscriber::builder()
-        .with_filter(EnvFilter::from_default_env().add_directive("echo=trace".parse()?))
+        .with_env_filter(EnvFilter::from_default_env().add_directive("echo=trace".parse()?))
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 
diff --git a/nightly-examples/examples/proxy_server.rs b/nightly-examples/examples/proxy_server.rs
index ed6270624b..952a330c9f 100644
--- a/nightly-examples/examples/proxy_server.rs
+++ b/nightly-examples/examples/proxy_server.rs
@@ -89,7 +89,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     use tracing_subscriber::{EnvFilter, FmtSubscriber};
 
     let subscriber = FmtSubscriber::builder()
-        .with_filter(EnvFilter::from_default_env().add_directive("proxy_server=trace".parse()?))
+        .with_env_filter(EnvFilter::from_default_env().add_directive("proxy_server=trace".parse()?))
         .finish();
     tracing::subscriber::set_global_default(subscriber)?;
 
diff --git a/tracing-subscriber/src/fmt/mod.rs b/tracing-subscriber/src/fmt/mod.rs
index 5d18cfb9bb..c95884a353 100644
--- a/tracing-subscriber/src/fmt/mod.rs
+++ b/tracing-subscriber/src/fmt/mod.rs
@@ -448,7 +448,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// use tracing_subscriber::{FmtSubscriber, EnvFilter};
     ///
     /// let subscriber = FmtSubscriber::builder()
-    ///     .with_filter(EnvFilter::from_default_env())
+    ///     .with_env_filter(EnvFilter::from_default_env())
     ///     .finish();
     /// ```
     ///
@@ -458,7 +458,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     ///
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let subscriber = FmtSubscriber::builder()
-    ///     .with_filter("my_crate=info,my_crate::my_mod=debug,[my_span]=trace")
+    ///     .with_env_filter("my_crate=info,my_crate::my_mod=debug,[my_span]=trace")
     ///     .finish();
     /// # Ok(()) }
     /// ```
@@ -479,7 +479,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     ///     .add_directive("my_crate::my_mod=debug".parse()?);
     ///
     /// let subscriber = FmtSubscriber::builder()
-    ///     .with_filter(filter)
+    ///     .with_env_filter(filter)
     ///     .finish();
     /// # Ok(())}
     /// ```

From c7b88aa77ee36590adb6b2740a974d162e2cb308 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 10:40:49 -0700
Subject: [PATCH 5/9] subscriber: rename feature flag

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 tracing-subscriber/Cargo.toml        |  7 +++++--
 tracing-subscriber/src/filter/mod.rs |  6 +++---
 tracing-subscriber/src/fmt/mod.rs    | 10 +++++-----
 tracing-subscriber/src/lib.rs        |  9 +++++----
 4 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/tracing-subscriber/Cargo.toml b/tracing-subscriber/Cargo.toml
index 2b2c0ebd7e..9ef25486a1 100644
--- a/tracing-subscriber/Cargo.toml
+++ b/tracing-subscriber/Cargo.toml
@@ -20,11 +20,14 @@ keywords = ["logging", "tracing", "metrics", "subscriber"]
 
 [features]
 
-default = ["filter", "smallvec", "fmt", "ansi", "chrono", "tracing-log"]
-filter = ["matchers", "regex", "lazy_static"]
+default = ["env-filter", "smallvec", "fmt", "ansi", "chrono", "tracing-log"]
+env-filter = ["matchers", "regex", "lazy_static"]
 fmt = ["owning_ref", "parking_lot"]
 ansi = ["fmt", "ansi_term"]
 
+# Alias for `env-filter`; renamed in version 0.1.2, and will be renamed in 0.2.
+filter = ["env-filter"]
+
 [dependencies]
 tracing-core = "0.1.2"
 crossbeam-utils = "0.6"
diff --git a/tracing-subscriber/src/filter/mod.rs b/tracing-subscriber/src/filter/mod.rs
index 21c38fe415..a7c73ef250 100644
--- a/tracing-subscriber/src/filter/mod.rs
+++ b/tracing-subscriber/src/filter/mod.rs
@@ -2,19 +2,19 @@
 //! subscriber.
 //!
 //! [`Layer`]: ../trait.Layer.html
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 mod env;
 mod level;
 
 pub use self::level::{LevelFilter, ParseError as LevelParseError};
 
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 pub use self::env::*;
 
 /// A `Layer` which filters spans and events based on a set of filter
 /// directives.
 ///
 /// **Note**: renamed to `EnvFilter` in 0.1.2; use that instead.
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 #[deprecated(since = "0.1.2", note = "renamed to `EnvFilter`")]
 pub type Filter = EnvFilter;
diff --git a/tracing-subscriber/src/fmt/mod.rs b/tracing-subscriber/src/fmt/mod.rs
index c95884a353..1e3745f978 100644
--- a/tracing-subscriber/src/fmt/mod.rs
+++ b/tracing-subscriber/src/fmt/mod.rs
@@ -383,7 +383,7 @@ where
     }
 }
 
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 impl<N, E, W> Builder<N, E, crate::EnvFilter, W>
 where
     Formatter<N, E, W>: tracing_core::Subscriber + 'static,
@@ -404,7 +404,7 @@ where
     }
 }
 
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 impl<N, E, W> Builder<N, E, crate::reload::Layer<crate::EnvFilter, Formatter<N, E, W>>, W>
 where
     Formatter<N, E, W>: tracing_core::Subscriber + 'static,
@@ -435,7 +435,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// Sets the [`EnvFilter`] that the subscriber will use to determine if
     /// a span or event is enabled.
     ///
-    /// Note that this method requires the "filter" feature flag to be enabled.
+    /// Note that this method requires the "env-filter" feature flag to be enabled.
     ///
     /// If a filter was previously set, or a maximum level was set by the
     /// [`with_max_level`] method, that value is replaced by the new filter.
@@ -485,7 +485,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// ```
     /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_max_level`]: #method.with_max_level
-    #[cfg(feature = "filter")]
+    #[cfg(feature = "env-filter")]
     pub fn with_env_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
     where
         Formatter<N, E, W>: tracing_core::Subscriber + 'static,
@@ -509,7 +509,7 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     ///
     /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_env_filter`]: #method.with_env_filter
-    #[cfg(feature = "filter")]
+    #[cfg(feature = "env-filter")]
     #[deprecated(since = "0.1.2", note = "renamed to `with_env_filter`")]
     pub fn with_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
     where
diff --git a/tracing-subscriber/src/lib.rs b/tracing-subscriber/src/lib.rs
index 485c1c2204..33b09abeb7 100644
--- a/tracing-subscriber/src/lib.rs
+++ b/tracing-subscriber/src/lib.rs
@@ -12,8 +12,10 @@
 //!
 //! ## Feature Flags
 //!
-//! - `filter`: Enables the [`EnvFilter`] type, which implements filtering similar
-//!   to the [`env_logger` crate]. Enabled by default.
+//! - `env-filter`: Enables the [`EnvFilter`] type, which implements filtering
+//!   similar to the [`env_logger` crate]. Enabled by default.
+//! - `filter`: Alias for `env-filter`. This feature flag was renamed in version
+//!   0.1.2, and will be removed in version 0.2.
 //! - `fmt`: Enables the [`fmt`] module, which provides a subscriber
 //!   implementation for printing formatted representations of trace events.
 //!   Enabled by default.
@@ -96,7 +98,7 @@ pub mod prelude;
 pub mod reload;
 pub(crate) mod thread;
 
-#[cfg(feature = "filter")]
+#[cfg(feature = "env-filter")]
 #[allow(deprecated)]
 pub use filter::{Filter, EnvFilter};
 
@@ -146,6 +148,5 @@ impl Default for CurrentSpan {
 }
 
 mod sealed {
-
     pub trait Sealed<A = ()> {}
 }

From 79d41244a3911f660dd3d85822813b54b6f5ba14 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 10:41:06 -0700
Subject: [PATCH 6/9] rustfmt

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 tracing-subscriber/src/fmt/mod.rs | 10 ++++++++--
 tracing-subscriber/src/lib.rs     |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/tracing-subscriber/src/fmt/mod.rs b/tracing-subscriber/src/fmt/mod.rs
index 1e3745f978..54f72e4943 100644
--- a/tracing-subscriber/src/fmt/mod.rs
+++ b/tracing-subscriber/src/fmt/mod.rs
@@ -486,7 +486,10 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// [`EnvFilter`]: ../filter/struct.EnvFilter.html
     /// [`with_max_level`]: #method.with_max_level
     #[cfg(feature = "env-filter")]
-    pub fn with_env_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
+    pub fn with_env_filter(
+        self,
+        filter: impl Into<crate::EnvFilter>,
+    ) -> Builder<N, E, crate::EnvFilter, W>
     where
         Formatter<N, E, W>: tracing_core::Subscriber + 'static,
     {
@@ -511,7 +514,10 @@ impl<N, E, F, W> Builder<N, E, F, W> {
     /// [`with_env_filter`]: #method.with_env_filter
     #[cfg(feature = "env-filter")]
     #[deprecated(since = "0.1.2", note = "renamed to `with_env_filter`")]
-    pub fn with_filter(self, filter: impl Into<crate::EnvFilter>) -> Builder<N, E, crate::EnvFilter, W>
+    pub fn with_filter(
+        self,
+        filter: impl Into<crate::EnvFilter>,
+    ) -> Builder<N, E, crate::EnvFilter, W>
     where
         Formatter<N, E, W>: tracing_core::Subscriber + 'static,
     {
diff --git a/tracing-subscriber/src/lib.rs b/tracing-subscriber/src/lib.rs
index 33b09abeb7..38c7e916d6 100644
--- a/tracing-subscriber/src/lib.rs
+++ b/tracing-subscriber/src/lib.rs
@@ -100,7 +100,7 @@ pub(crate) mod thread;
 
 #[cfg(feature = "env-filter")]
 #[allow(deprecated)]
-pub use filter::{Filter, EnvFilter};
+pub use filter::{EnvFilter, Filter};
 
 pub use layer::Layer;
 

From 5cfb256546731c2b5b7abb6eb06977577607d8b1 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 10:45:51 -0700
Subject: [PATCH 7/9] fix accidental rename

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 examples/examples/tower-load.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/examples/tower-load.rs b/examples/examples/tower-load.rs
index 815b9e9093..212bdcf009 100644
--- a/examples/examples/tower-load.rs
+++ b/examples/examples/tower-load.rs
@@ -37,7 +37,7 @@ use tracing_subscriber::FmtSubscriber;
 fn main() {
     let builder = FmtSubscriber::builder()
         .with_env_filter("info,tower_load=debug")
-        .with_env_filter_reloading();
+        .with_filter_reloading();
     let handle = builder.reload_handle();
 
     let _ = tracing::subscriber::set_global_default(builder.finish());

From 1adf77e12a8c5fca49e2bb52d777ccce18396e5f Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 11:14:15 -0700
Subject: [PATCH 8/9] Apply suggestions from code review

Co-Authored-By: Benjamin Saunders <ben.e.saunders@gmail.com>
---
 tracing-subscriber/Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tracing-subscriber/Cargo.toml b/tracing-subscriber/Cargo.toml
index 9ef25486a1..f1d343fd54 100644
--- a/tracing-subscriber/Cargo.toml
+++ b/tracing-subscriber/Cargo.toml
@@ -25,7 +25,7 @@ env-filter = ["matchers", "regex", "lazy_static"]
 fmt = ["owning_ref", "parking_lot"]
 ansi = ["fmt", "ansi_term"]
 
-# Alias for `env-filter`; renamed in version 0.1.2, and will be renamed in 0.2.
+# Alias for `env-filter`; renamed in version 0.1.2, and will be removed in 0.2.
 filter = ["env-filter"]
 
 [dependencies]

From 3b2e0ee6685a9b20f1b3126b3f5e582191697583 Mon Sep 17 00:00:00 2001
From: Eliza Weisman <eliza@buoyant.io>
Date: Thu, 12 Sep 2019 11:16:47 -0700
Subject: [PATCH 9/9] subscriber: emit deprecation warnings for "filter"

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
---
 tracing-subscriber/src/filter/env/mod.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tracing-subscriber/src/filter/env/mod.rs b/tracing-subscriber/src/filter/env/mod.rs
index 5133e7bc1f..d3518cac53 100644
--- a/tracing-subscriber/src/filter/env/mod.rs
+++ b/tracing-subscriber/src/filter/env/mod.rs
@@ -29,6 +29,13 @@ use tracing_core::{
 /// A `Layer` which filters spans and events based on a set of filter
 /// directives.
 // TODO(eliza): document filter directive syntax?
+#[cfg_attr(
+    feature = "filter",
+    deprecated(
+        since = "0.1.2",
+        note = "the `filter` feature flag was renamed to `env-filter` and will be removed in 0.2",
+    )
+)]
 #[derive(Debug)]
 pub struct EnvFilter {
     // TODO: eventually, this should be exposed by the registry.