feat(boil): Improve empty image version filter error

This now reports the image name and the filtered version(s) in the
error. Previously, users would have to guess which image and version
yielded an empty list.

Author: Techassi

rust/boil/src/core/bakefile.rs

@@ -70,14 +70,17 @@ pub enum Error {
 
 #[derive(Debug, Snafu)]
 pub enum TargetsError {
-    #[snafu(display("encountered invalid image version"))]
-    InvalidImageVersion { source: ImageConfigError },
-
     #[snafu(display("failed to read image config"))]
     ReadImageConfig { source: ImageConfigError },
 
     #[snafu(display("failed to resolve parent directory of image config at {path}", path = path.display()))]
     ResolveParentDirectory { path: PathBuf },
+
+    #[snafu(display("provided filter version(s) ({image_name}={versions}) yielded empty list", versions = versions.join(", ")))]
+    EmptyFilter {
+        versions: Vec<String>,
+        image_name: String,
+    },
 }
 
 #[derive(Debug, Default)]
@@ -187,9 +190,15 @@ impl Targets {
                 ImageConfig::from_file(image_config_path).context(ReadImageConfigSnafu)?;
 
             // Create a list of image versions we need to generate targets for in the bakefile.
-            image_config
-                .filter_by_version(&image.versions)
-                .context(InvalidImageVersionSnafu)?;
+            image_config.filter_by_version(&image.versions);
+
+            ensure!(
+                !image_config.versions.is_empty(),
+                EmptyFilterSnafu {
+                    versions: image.versions.clone(),
+                    image_name: image.name.clone(),
+                }
+            );
 
             targets.insert_targets(image.name.clone(), image_config, &options, true)?;
         }
@@ -222,9 +231,15 @@ impl Targets {
                     let mut image_config =
                         ImageConfig::from_file(image_config_path).context(ReadImageConfigSnafu)?;
 
-                    image_config
-                        .filter_by_version(&[image_version])
-                        .context(InvalidImageVersionSnafu)?;
+                    image_config.filter_by_version(&[image_version]);
+
+                    ensure!(
+                        !image_config.versions.is_empty(),
+                        EmptyFilterSnafu {
+                            versions: vec![image_version.clone()],
+                            image_name: image_name.clone(),
+                        }
+                    );
 
                     // Wowzers, recursion!
                     self.insert_targets(image_name.clone(), image_config, options, false)?;

rust/boil/src/core/image.rs

@@ -108,9 +108,6 @@ pub enum ImageConfigError {
 
     #[snafu(display("failed to deserialize config file from TOML"))]
     Deserialize { source: toml::de::Error },
-
-    #[snafu(display("provided filter version yielded empty list"))]
-    EmptyFilter,
 }
 
 #[derive(Debug, Deserialize)]
@@ -130,16 +127,13 @@ impl ImageConfig {
     pub const FLAT_CONFIG_GLOB_PATTERN: &str = "*/boil-config.toml";
 
     /// This function removes versions in the config filtered out by `versions`.
-    pub fn filter_by_version<V>(&mut self, versions: &[V]) -> Result<(), ImageConfigError>
+    pub fn filter_by_version<V>(&mut self, versions: &[V])
     where
         V: AsRef<str> + PartialEq,
     {
         self.versions.retain(|image_version, _| {
             versions.is_empty() || versions.iter().any(|v| v.as_ref() == image_version)
         });
-
-        ensure!(!self.versions.is_empty(), EmptyFilterSnafu);
-        Ok(())
     }
 }