Refactor away def_file module into CommandVersionRegistry

CHANGELOG.md

@@ -19,6 +19,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   affect people building from source.
 - Migrate to `clap@v4`. This changes the way the help text is rendered. In terms
   of behavior, nothing should change.
+- Change some of the errors management to use the
+  [`anyhow` crate](https://crates.io/crates/anyhow). This should make the errors
+  affected by this change clearer and give more context.
+- Rewrite how command versions are managed internally. This is a purely internal
+  change and should not affect users in any way.
 
 <!-- section:previous-releases -->
 ## [v1.2.1] 2022-06-24

Cargo.toml

@@ -32,12 +32,14 @@ opt-level = 3
 opt-level = 3
 
 [dependencies]
+anyhow = "1.0"
 clap = { version = "4.0.32", features = ["cargo", "wrap_help"] }
 toml = "0.5.10"
 console = "0.15.3"
 lazy_static = "1.4.0"
 dialoguer = "0.10.2"
 glob = "0.3.0"
+thiserror = "1.0"
 
 [dependencies.regex]
 version = "1"
@@ -52,6 +54,7 @@ predicates = "2.1.5"
 rand = "0.8"
 serde = "1.0.152"
 test-case = "2.2.2"
+tempfile = "3"
 
 [build-dependencies]
 clap = { version = "4.0.32", features = ["cargo"] }

src/checks.rs

@@ -1,4 +1,4 @@
-use crate::config;
+use crate::environment;
 use std::env;
 
 use console::style;
@@ -28,7 +28,7 @@ pub fn check_shim_in_path() {
     let path = env::var("PATH").unwrap_or_default();
     let mut parts = env::split_paths(&path);
 
-    let shim_dir = config::shim_dir();
+    let shim_dir = environment::shim_dir();
     if !parts.any(|part| part == shim_dir) {
         let term = console::Term::stdout();
         let (_, term_width) = term.size();

src/command.rs

@@ -1,3 +1,4 @@
+use crate::command_version::CommandVersionRegistry;
 use crate::use_file;
 use std::env;
 use std::fs;
@@ -21,3 +22,15 @@ pub fn find_system_bin(command: &str) -> Option<PathBuf> {
         .map(|p| fs::canonicalize(p).unwrap())
         .find(|p| p != &current_exe)
 }
+
+pub fn find_selected_binary(
+    command_version_registry: &CommandVersionRegistry,
+    command_name: &str,
+) -> Option<PathBuf> {
+    match find_selected_version(command_name) {
+        Some(version) => command_version_registry
+            .get(command_name, &version)
+            .map(|v| v.path),
+        None => find_system_bin(command_name),
+    }
+}