fix(cli): improve error message for invalid config (#1200)

Previously an invalid `Dioxus.toml` file would yield this error when running e.g. `dx serve`:

```
Error: Failed to load `Dioxus.toml` because: Dioxus.toml parse failed
```

This doesn't give any indication why it failed to parse. This commit updates it to include why the parsing failed, e.g.:

```
Error: Failed to load Dioxus config because: Dioxus.toml missing field `name` for key `application` at line 38 column 1
```

I initially had it format the message to include `Dioxus.toml:38:1` to be clickable in some terminals, but the location specified didn't always seem particularly relevant to the actual problem so I left it as-is.

This also fixes what I believe would be an issue on case-sensitive file systems where if `dioxus.toml` existed it would try to read `Dioxus.toml`.

I'm still fairly new to Rust, so the `.as_path()` calls may not be the best way to deal with the fact that the borrow checker wouldn't let me re-use `crate_dir` and `dioxus_conf_file`. I'm open to suggestions!

packages/cli/src/config.rs

@@ -1,6 +1,9 @@
 use crate::error::Result;
 use serde::{Deserialize, Serialize};
-use std::{collections::HashMap, path::PathBuf};
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct DioxusConfig {
@@ -19,27 +22,36 @@ fn default_plugin() -> toml::Value {
 impl DioxusConfig {
     pub fn load() -> crate::error::Result<Option<DioxusConfig>> {
         let Ok(crate_dir) = crate::cargo::crate_root() else { return Ok(None); };
+        let crate_dir = crate_dir.as_path();
 
-        // we support either `Dioxus.toml` or `Cargo.toml`
         let Some(dioxus_conf_file) = acquire_dioxus_toml(crate_dir) else {
             return Ok(None);
         };
 
+        let dioxus_conf_file = dioxus_conf_file.as_path();
         toml::from_str::<DioxusConfig>(&std::fs::read_to_string(dioxus_conf_file)?)
-            .map_err(|_| crate::Error::Unique("Dioxus.toml parse failed".into()))
+            .map_err(|err| {
+                let error_location = dioxus_conf_file
+                    .strip_prefix(crate_dir)
+                    .unwrap_or(dioxus_conf_file)
+                    .display();
+                crate::Error::Unique(format!("{error_location} {err}"))
+            })
             .map(Some)
     }
 }
 
-fn acquire_dioxus_toml(dir: PathBuf) -> Option<PathBuf> {
+fn acquire_dioxus_toml(dir: &Path) -> Option<PathBuf> {
     // prefer uppercase
-    if dir.join("Dioxus.toml").is_file() {
-        return Some(dir.join("Dioxus.toml"));
+    let uppercase_conf = dir.join("Dioxus.toml");
+    if uppercase_conf.is_file() {
+        return Some(uppercase_conf);
     }
 
     // lowercase is fine too
-    if dir.join("dioxus.toml").is_file() {
-        return Some(dir.join("Dioxus.toml"));
+    let lowercase_conf = dir.join("dioxus.toml");
+    if lowercase_conf.is_file() {
+        return Some(lowercase_conf);
     }
 
     None

packages/cli/src/main.rs

@@ -14,7 +14,7 @@ async fn main() -> anyhow::Result<()> {
     set_up_logging();
 
     let _dioxus_config = DioxusConfig::load()
-        .map_err(|e| anyhow!("Failed to load `Dioxus.toml` because: {e}"))?
+        .map_err(|e| anyhow!("Failed to load Dioxus config because: {e}"))?
         .unwrap_or_else(|| {
             log::warn!("You appear to be creating a Dioxus project from scratch; we will use the default config");
             DioxusConfig::default()