chore: Separate InlineError::MissingStyleSheet error variant to improve debugging experience

Stranger6667 · Stranger6667 · commit d91f3245b3f6 · 2022-01-09T10:20:25.000+01:00
Ref: #124
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Separate `InlineError::MissingStyleSheet` error variant to improve debugging experience. [#124](https://github.com/Stranger6667/css-inline/issues/124)
+
 ## [0.7.6] - 2022-01-08
 
 ### Fixed
diff --git a/bindings/python/CHANGELOG.md b/bindings/python/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Include missing stylesheet path to `InlineError` message. [#124](https://github.com/Stranger6667/css-inline/issues/124)
+
 ## [0.7.8] - 2022-01-08
 
 ### Fixed
diff --git a/bindings/python/src/lib.rs b/bindings/python/src/lib.rs
@@ -42,6 +42,9 @@ impl From<InlineErrorWrapper> for PyErr {
             rust_inline::InlineError::ParseError(message) => {
                 InlineError::new_err(message.to_string())
             }
+            rust_inline::InlineError::MissingStyleSheet { .. } => {
+                InlineError::new_err(error.0.to_string())
+            }
         }
     }
 }
diff --git a/bindings/python/tests-py/test_inlining.py b/bindings/python/tests-py/test_inlining.py
@@ -61,6 +61,22 @@ def test_inline_many_wrong_type():
         css_inline.inline_many([1])
 
 
+def test_missing_stylesheet():
+    with pytest.raises(
+        css_inline.InlineError, match="Missing stylesheet file: tests/missing.css"
+    ):
+        css_inline.inline(
+            """<html>
+<head>
+<link href="tests/missing.css" rel="stylesheet" type="text/css">
+</head>
+<body>
+<h1>Big Text</h1>
+</body>
+</html>"""
+        )
+
+
 def test_invalid_base_url():
     with pytest.raises(ValueError):
         css_inline.CSSInliner(base_url="foo")
diff --git a/css-inline/src/error.rs b/css-inline/src/error.rs
@@ -11,6 +11,11 @@ use std::{
 /// Inlining error
 #[derive(Debug)]
 pub enum InlineError {
+    /// Missing stylesheet file.
+    MissingStyleSheet {
+        /// Path to the missing file.
+        path: String,
+    },
     /// Input-output error. May happen during writing the resulting HTML.
     IO(io::Error),
     /// Network-related problem. E.g. resource is not available.
@@ -38,6 +43,9 @@ impl Display for InlineError {
             Self::IO(error) => error.fmt(f),
             Self::Network(error) => error.fmt(f),
             Self::ParseError(error) => f.write_str(error),
+            Self::MissingStyleSheet { path } => {
+                f.write_fmt(format_args!("Missing stylesheet file: {}", path))
+            }
         }
     }
 }
diff --git a/css-inline/src/lib.rs b/css-inline/src/lib.rs
@@ -115,7 +115,12 @@ mod parser;
 use ahash::AHashMap;
 pub use error::InlineError;
 use smallvec::{smallvec, SmallVec};
-use std::{borrow::Cow, collections::hash_map::Entry, fs, io::Write};
+use std::{
+    borrow::Cow,
+    collections::hash_map::Entry,
+    fs,
+    io::{ErrorKind, Write},
+};
 pub use url::{ParseError, Url};
 
 /// Replace double quotes in property values.
@@ -404,7 +409,12 @@ fn load_external(location: &str) -> Result<String> {
         let response = request.send()?;
         Ok(response.text()?)
     } else {
-        fs::read_to_string(location).map_err(InlineError::IO)
+        fs::read_to_string(location).map_err(|error| match error.kind() {
+            ErrorKind::NotFound => InlineError::MissingStyleSheet {
+                path: location.to_string(),
+            },
+            _ => InlineError::IO(error),
+        })
     }
 }
 
diff --git a/css-inline/tests/test_inlining.rs b/css-inline/tests/test_inlining.rs
@@ -1,6 +1,6 @@
 #[macro_use]
 mod utils;
-use css_inline::{inline, CSSInliner, InlineOptions, Url};
+use css_inline::{inline, CSSInliner, InlineError, InlineOptions, Url};
 
 #[test]
 fn no_existing_style() {
@@ -309,6 +309,25 @@ h2 { color: red; }
     ))
 }
 
+#[test]
+fn missing_stylesheet() {
+    let html = r#"
+<html>
+<head>
+<link href="tests/missing.css" rel="stylesheet" type="text/css">
+</head>
+<body>
+<h1>Big Text</h1>
+</body>
+</html>"#;
+    match inline(html).expect_err("Should be an error") {
+        InlineError::MissingStyleSheet { path } => {
+            assert_eq!(path, String::from("tests/missing.css"))
+        }
+        _ => panic!("Invalid error type"),
+    }
+}
+
 #[test]
 fn remote_file_stylesheet_disable() {
     let html = r#"

Original file line number	Diff line number	Diff line change
`@@ -42,6 +42,9 @@ impl From<InlineErrorWrapper> for PyErr {`
`42`	`42`	`rust_inline::InlineError::ParseError(message) => {`
`43`	`43`	`InlineError::new_err(message.to_string())`
`44`	`44`	`}`
	`45`	`+ rust_inline::InlineError::MissingStyleSheet { .. } => {`
	`46`	`+ InlineError::new_err(error.0.to_string())`
	`47`	`+ }`
`45`	`48`	`}`
`46`	`49`	`}`
`47`	`50`	`}`