Clippy fixes. (#846)

* Clippy fixes.

* Drop support for Python 3.6

* Remove other 3.6

* Re-enabling caches for build (5h + seems too long and issue seems
solved)

https://github.com/actions/virtual-environments/issues/572

* `npm audit fix`.

* Fix yaml ?

* Pyarrow issue fixed: https://github.com/huggingface/datasets/pull/2268

* Installing dev libraries.

* Install python dev elsewhere ?

* Typo.

* No sudo.

* ...

* Testing the GH again.

* Maybe v2 will fix ?

* Fixing tests on MacOS Python 3.8+

bindings/python/src/encoding.rs

@@ -51,7 +51,7 @@ impl PyEncoding {
         let data = serde_json::to_string(&self.encoding).map_err(|e| {
             exceptions::PyException::new_err(format!(
                 "Error while attempting to pickle Encoding: {}",
-                e.to_string()
+                e
             ))
         })?;
         Ok(PyBytes::new(py, data.as_bytes()).to_object(py))
@@ -63,7 +63,7 @@ impl PyEncoding {
                 self.encoding = serde_json::from_slice(s.as_bytes()).map_err(|e| {
                     exceptions::PyException::new_err(format!(
                         "Error while attempting to unpickle Encoding: {}",
-                        e.to_string()
+                        e
                     ))
                 })?;
                 Ok(())

bindings/python/src/models.rs

@@ -103,7 +103,7 @@ impl PyModel {
         let data = serde_json::to_string(&self.model).map_err(|e| {
             exceptions::PyException::new_err(format!(
                 "Error while attempting to pickle Model: {}",
-                e.to_string()
+                e
             ))
         })?;
         Ok(PyBytes::new(py, data.as_bytes()).to_object(py))
@@ -115,7 +115,7 @@ impl PyModel {
                 self.model = serde_json::from_slice(s.as_bytes()).map_err(|e| {
                     exceptions::PyException::new_err(format!(
                         "Error while attempting to unpickle Model: {}",
-                        e.to_string()
+                        e
                     ))
                 })?;
                 Ok(())

bindings/python/src/pre_tokenizers.rs

@@ -112,7 +112,7 @@ impl PyPreTokenizer {
         let data = serde_json::to_string(&self.pretok).map_err(|e| {
             exceptions::PyException::new_err(format!(
                 "Error while attempting to pickle PreTokenizer: {}",
-                e.to_string()
+                e
             ))
         })?;
         Ok(PyBytes::new(py, data.as_bytes()).to_object(py))

bindings/python/src/processors.rs

@@ -71,7 +71,7 @@ impl PyPostProcessor {
         let data = serde_json::to_string(self.processor.as_ref()).map_err(|e| {
             exceptions::PyException::new_err(format!(
                 "Error while attempting to pickle PostProcessor: {}",
-                e.to_string()
+                e
             ))
         })?;
         Ok(PyBytes::new(py, data.as_bytes()).to_object(py))
@@ -83,7 +83,7 @@ impl PyPostProcessor {
                 self.processor = serde_json::from_slice(s.as_bytes()).map_err(|e| {
                     exceptions::PyException::new_err(format!(
                         "Error while attempting to unpickle PostProcessor: {}",
-                        e.to_string()
+                        e
                     ))
                 })?;
                 Ok(())

bindings/python/src/utils/normalization.rs

@@ -559,7 +559,7 @@ impl PyNormalizedStringRefMut {
 
     fn filter(&mut self, func: &PyAny) -> PyResult<()> {
         self.inner
-            .map_mut(|mut n| filter(&mut n, func))
+            .map_mut(|n| filter(n, func))
             .ok_or_else(PyNormalizedStringRefMut::destroyed_error)??;
         Ok(())
     }
@@ -573,7 +573,7 @@ impl PyNormalizedStringRefMut {
 
     fn map(&mut self, func: &PyAny) -> PyResult<()> {
         self.inner
-            .map_mut(|mut n| map(&mut n, func))
+            .map_mut(|n| map(n, func))
             .ok_or_else(PyNormalizedStringRefMut::destroyed_error)??;
         Ok(())
     }

bindings/python/tests/utils.py

@@ -98,6 +98,10 @@ def doc_pipeline_bert_tokenizer(data_dir):
     )
 
 
+# On MacOS Python 3.8+ the default was modified to `spawn`, we need `fork` in tests.
+mp.set_start_method("fork")
+
+
 def multiprocessing_with_parallelism(tokenizer, enabled: bool):
     """
     This helper can be used to test that disabling parallelism avoids dead locks when the