perf: Use ToString trait during error handling to avoid using a formatter

Author: Stranger6667

python/CHANGELOG.md

@@ -11,6 +11,11 @@
 
 - Switch from `openssl` to `rustls` in `attohttpc` dependency. [#49](https://github.com/Stranger6667/css-inline/issues/49)
 
+
+### Performance
+
+- Use `ToString` trait during error handling to avoid using a formatter.
+
 ## [0.3.2] - 2020-07-09
 
 ### Fixed

python/benches/bench.py

@@ -1,4 +1,5 @@
 import multiprocessing
+from contextlib import suppress
 
 import inlinestyler.utils
 import premailer
@@ -204,3 +205,12 @@ def test_realistic(benchmark, func):
 @pytest.mark.benchmark(group="realistic many")
 def test_realistic_many(benchmark, func):
     benchmark(func, REALISTIC_HTMLS)
+
+
+@pytest.mark.benchmark(group="exception")
+def test_exception(benchmark):
+    def func():
+        with suppress(ValueError):
+            css_inline.inline("", base_url="!wrong!")
+
+    benchmark(func)

python/src/lib.rs

@@ -13,8 +13,8 @@ struct InlineErrorWrapper(rust_inline::InlineError);
 impl From<InlineErrorWrapper> for PyErr {
     fn from(error: InlineErrorWrapper) -> Self {
         match error.0 {
-            rust_inline::InlineError::IO(error) => InlineError::py_err(format!("{}", error)),
-            rust_inline::InlineError::Network(error) => InlineError::py_err(format!("{}", error)),
+            rust_inline::InlineError::IO(error) => InlineError::py_err(error.to_string()),
+            rust_inline::InlineError::Network(error) => InlineError::py_err(error.to_string()),
             rust_inline::InlineError::ParseError(message) => InlineError::py_err(message),
         }
     }
@@ -24,7 +24,7 @@ struct UrlError(url::ParseError);
 
 impl From<UrlError> for PyErr {
     fn from(error: UrlError) -> Self {
-        exceptions::ValueError::py_err(format!("{}", error.0))
+        exceptions::ValueError::py_err(error.0.to_string())
     }
 }