refactor: have per-module error enums

This means that a function that parses step bindings can't return an
error that the document is missing a title. Such an error return would
be nonsensical, and we use the Rust type system to prevent it, at a
small cost of being a bit verbose.

Additional benefit is that the library portion of Obnam doesn't return
anyhow::Result values anymore.

1 files changed, 2 insertions, 6 deletions

diff --git a/src/cmd/show_gen.rs b/src/cmd/show_gen.rs
index d355389..3dcdbf2 100644
--- a/src/cmd/show_gen.rs
+++ b/src/cmd/show_gen.rs
@@ -5,7 +5,7 @@ use crate::fsentry::FilesystemKind;
 use indicatif::HumanBytes;
 use tempfile::NamedTempFile;
 
-pub fn show_generation(config: &ClientConfig, gen_ref: &str) -> anyhow::Result<()> {
+pub fn show_generation(config: &ClientConfig, gen_ref: &str) -> Result<(), ObnamError> {
     // Create a named temporary file. We don't meed the open file
     // handle, so we discard that.
     let dbname = {
@@ -17,11 +17,7 @@ pub fn show_generation(config: &ClientConfig, gen_ref: &str) -> anyhow::Result<(
     let client = BackupClient::new(&config.server_url)?;
 
     let genlist = client.list_generations()?;
-    let gen_id: String = match genlist.resolve(gen_ref) {
-        None => return Err(ObnamError::UnknownGeneration(gen_ref.to_string()).into()),
-        Some(id) => id,
-    };
-
+    let gen_id: String = genlist.resolve(gen_ref)?;
     let gen = client.fetch_generation(&gen_id, &dbname)?;
     let files = gen.files()?;