feat!: simplify Pipeline::new() by reomving the metadata collection.

It's required, but in practice has no effect as it's initialized at
just the right time anyway, which is when it does matter.

Also, re-export `gix_attributes as attributes` to allow using the types
it mentions in the public API.

Author: Byron

gix-filter/src/lib.rs

@@ -10,6 +10,9 @@
 //! or not to apply such a filter.
 #![deny(rust_2018_idioms, missing_docs, unsafe_code)]
 
+/// The `gix-attributes` crate whose types are mentioned in the public API of [Pipeline::convert_to_worktree()].
+pub use gix_attributes as attributes;
+
 use bstr::BString;
 /// A forwarding of the `encoding_rs` crate for its types and convenience.
 pub use encoding_rs as encoding;

gix-filter/src/pipeline/mod.rs

@@ -52,18 +52,13 @@ const ATTRS: [&str; 6] = ["crlf", "ident", "filter", "eol", "text", "working-tre
 
 /// Lifecycle
 impl Pipeline {
-    /// Create a new pipeline with configured `drivers` (which should be considered safe to invoke) with `context` as well as
-    /// a way to initialize our attributes with `collection`.
+    /// Create a new pipeline with configured `drivers` (which should be considered safe to invoke), which are passed `context`.
     /// `eol_config` serves as fallback to understand how to convert line endings if no line-ending attributes are present.
     /// `crlf_roundtrip_check` corresponds to the git-configuration of `core.safecrlf`.
     /// `object_hash` is relevant for the `ident` filter.
-    pub fn new(
-        collection: &gix_attributes::search::MetadataCollection,
-        context: gix_command::Context,
-        options: Options,
-    ) -> Self {
+    pub fn new(context: gix_command::Context, options: Options) -> Self {
         let mut attrs = gix_attributes::search::Outcome::default();
-        attrs.initialize_with_selection(collection, ATTRS);
+        attrs.initialize_with_selection(&Default::default(), ATTRS);
         Pipeline {
             attrs,
             context: Context::default(),
@@ -83,8 +78,7 @@ impl Pipeline {
 
 impl Default for Pipeline {
     fn default() -> Self {
-        let collection = Default::default();
-        Pipeline::new(&collection, Default::default(), Default::default())
+        Pipeline::new(Default::default(), Default::default())
     }
 }
 

gix-filter/tests/driver/mod.rs

@@ -138,17 +138,18 @@ pub(crate) mod apply {
     fn a_crashing_process_can_restart_it() -> crate::Result {
         let mut state = gix_filter::driver::State::default();
         let driver = driver_with_process();
+        let err = match state.apply(
+            &driver,
+            &mut std::io::empty(),
+            Operation::Smudge,
+            context_from_path("fail"),
+        ) {
+            Ok(_) => panic!("expecting an error as invalid context was passed"),
+            Err(err) => err,
+        };
         assert!(
-            matches!(
-                state.apply(
-                    &driver,
-                    &mut std::io::empty(),
-                    Operation::Smudge,
-                    context_from_path("fail")
-                ),
-                Err(gix_filter::driver::apply::Error::ProcessInvoke { .. })
-            ),
-            "cannot invoke if failure is requested"
+            matches!(err, gix_filter::driver::apply::Error::ProcessInvoke { .. }),
+            "{err:?}: cannot invoke if failure is requested"
         );
 
         let mut filtered = state

gix-filter/tests/pipeline/mod.rs

@@ -58,7 +58,6 @@ fn pipeline(
     let cache = attribute_cache(name)?;
     let (drivers, encodings_with_roundtrip_check, crlf_roundtrip_check, eol_config) = init();
     let pipe = gix_filter::Pipeline::new(
-        cache.attributes_collection(),
         Default::default(),
         gix_filter::pipeline::Options {
             drivers,