Extract yaml file parsing into own function

.rustfmt.toml

@@ -7,4 +7,3 @@ match_block_trailing_comma = true
 max_width = 120
 overflow_delimited_expr = true
 reorder_impl_items = true
-struct_field_align_threshold = 20

src/helm_config.rs

@@ -1,5 +1,7 @@
 use std::collections::HashMap;
 
+use anyhow::Context;
+use git2::{DiffFile, Repository};
 use serde::{Deserialize, Serialize};
 
 #[allow(clippy::module_name_repetitions)]
@@ -9,6 +11,17 @@ pub struct ImageRefs {
     pub container_images: HashMap<String, ImageRef>,
 }
 
+impl ImageRefs {
+    pub fn parse(repo: &Repository, diff_file: DiffFile) -> Result<Self, anyhow::Error> {
+        let blob_id = diff_file.id();
+        let blob = repo
+            .find_blob(blob_id)
+            .with_context(|| format!("cannot find Git blob {blob_id}"))?;
+        Ok(serde_yml::from_slice(blob.content())
+            .with_context(|| format!("cannot parse yaml file {:?}", diff_file.path()))?)
+    }
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 pub struct ImageRef {
     pub account:    String,

src/main.rs

@@ -137,28 +137,24 @@ fn find_values_yaml(workspace: String, base: &str, head: &str) -> Result<Vec<Rep
             continue;
         }
 
-        let new_images_content = repo.find_blob(new_file.id())?;
-        let new_image_config: ImageRefs = serde_yml::from_slice(new_images_content.content())?;
+        let new_image_refs = ImageRefs::parse(&repo, new_file)?;
 
         let old_file = diff_delta.old_file();
         if old_file.exists() {
-            let old_images_content = repo.find_blob(old_file.id())?;
-            let old_image_config: ImageRefs = serde_yml::from_slice(old_images_content.content())?;
+            let old_image_refs = ImageRefs::parse(&repo, old_file)?;
 
-            for (name, image) in &new_image_config.container_images {
+            for (name, image) in &new_image_refs.container_images {
                 for source in &image.sources {
                     changes.push(RepoChangeset {
                         name: name.clone(),
                         remote: util::Remote::parse(&source.repo)?,
                         // TODO: iterate over sources
-                        base_commit: old_image_config.container_images[name].sources[0].commit.clone(),
+                        base_commit: old_image_refs.container_images[name].sources[0].commit.clone(),
                         head_commit: source.commit.clone(),
                         changes: Vec::new(),
                     });
                 }
             }
-
-            continue;
         }
     }