improved instance module

src/instance.rs

@@ -5,7 +5,8 @@ use std::{
 };
 
 use globset::{Glob, GlobSet, GlobSetBuilder};
-use log::{error, warn};
+use log::warn;
+use thiserror::Error;
 
 use crate::{
     file_conflict_solver::ConflictSolver,
@@ -20,7 +21,7 @@ pub fn insert_mod_to_instance(
     from_mod: &ModConfig,
     files: &[ModFile],
     priority: isize,
-) -> bool {
+) -> Result<(), InststanceError> {
     let mut solver = ConflictSolver::new();
 
     let mut installed_files: Vec<(ModFile, &InstalledMod)> = Vec::new();
@@ -33,21 +34,18 @@ pub fn insert_mod_to_instance(
 
     for (file, from_mod) in &installed_files {
         if let Some(conflict) = solver.add_file(file, from_mod) {
-            warn!("Got file conflict on already added file: {:?}", conflict);
+            warn!("File conflict on already added file: {:?}", conflict);
         }
     }
 
     let new_mod = InstalledMod::new(from_mod.id(), priority);
     for file in files {
         if let Some(conflict) = solver.add_file(file, &new_mod) {
-            error!(
+            return Err(InststanceError::FileConflict {
-                "File conflict detected at: {} between {} and {}",
+                lhs_mod_id: conflict.lhs_mod.mod_id().to_owned(),
-                conflict.rhs_file.dst().to_string_lossy(),
+                rhs_mod_id: conflict.rhs_mod.mod_id().to_owned(),
-                conflict.lhs_mod.mod_id(),
+                path: conflict.rhs_file.dst().to_owned(),
-                conflict.rhs_mod.mod_id()
+            });
-            );
-
-            return false;
         }
     }
 
@@ -72,7 +70,7 @@ pub fn insert_mod_to_instance(
         instance.update_or_create_mod(&installed_mod);
     }
 
-    true
+    Ok(())
 }
 
 pub fn files_to_install_mod(
@@ -123,13 +121,18 @@ fn install_fomod(
     let module_config = fomod::Config::load_from_file(module_config_path)?;
 
     // TODO: add active plugins from instance config
-    let files = run_fomod_installer(module_config, &[], install_prompt::prompt)?;
+    let files = run_fomod_installer(module_config, &[], install_prompt::prompt)
+        .map_err(|_| InststanceError::FomodRunInstaller)?;
 
     let mod_files: Vec<_> = files
         .iter()
-        .flat_map(|f| ModFile::from_installer(f.clone(), &mod_root).unwrap())
+        .map(|f| {
+            ModFile::from_installer(f.clone(), &mod_root).map_err(InststanceError::FomodFinalize)
+        })
+        .collect::<Result<Vec<_>, _>>()?
+        .into_iter()
+        .flatten()
         .collect();
-
     Ok(mod_files)
 }
 
@@ -202,3 +205,19 @@ fn should_be_included(path: impl AsRef<Path>) -> bool {
         )
     )
 }
+
+#[derive(Debug, Error)]
+pub enum InststanceError {
+    #[error("Two mods write the same file")]
+    FileConflict {
+        lhs_mod_id: String,
+        rhs_mod_id: String,
+        path: PathBuf,
+    },
+
+    #[error("Failed to run fomod installer")]
+    FomodRunInstaller,
+
+    #[error("Failed to handle results of fomod installer")]
+    FomodFinalize(io::Error),
+}

src/main.rs

@@ -1,13 +1,13 @@
 use anyhow::anyhow;
 use clap::Parser;
-use log::debug;
+use log::{debug, error, info};
 use std::{error::Error, path::Path};
 
 use crate::{
     activator::activate_instance,
     cli::Args,
     instance::{files_to_install_mod, insert_mod_to_instance},
-    nexus::{NexusAPI,download_nxm},
+    nexus::{NexusAPI, download_nxm},
     types::RootConfig,
 };
 
@@ -41,13 +41,40 @@ fn command_add(root_config: &RootConfig, instance_id: &str, mod_id: &str) -> any
 
     let files = files_to_install_mod(root_config, &instance, mod_to_install)?;
 
-    if !insert_mod_to_instance(&mut instance, mod_to_install, &files, 0) {
+    match insert_mod_to_instance(&mut instance, mod_to_install, &files, 0) {
-        return Err(anyhow!("File conflict"));
+        Ok(_) => {
+            instance.save_to_file()?;
+            Ok(())
+        }
+        Err(err) => {
+            match &err {
+                instance::InststanceError::FileConflict {
+                    lhs_mod_id,
+                    rhs_mod_id,
+                    path,
+                } => {
+                    error!(
+                        "File conflict between {} and {} at {}",
+                        lhs_mod_id,
+                        rhs_mod_id,
+                        path.to_string_lossy()
+                    );
+                    info!("To resolve file conflicts give one mod a higher priority in the config");
+                }
+                instance::InststanceError::FomodRunInstaller => {
+                    error!("Failed to run FOMod installer");
+                }
+                instance::InststanceError::FomodFinalize(error) => {
+                    error!(
+                        "FOMod installer finished but failed to finalize result: {}",
+                        error
+                    );
+                }
+            };
+
+            Err(err.into())
+        }
     }
-
-    instance.save_to_file()?;
-
-    Ok(())
 }
 
 fn command_order(root_config: &RootConfig, instance_id: &str) -> anyhow::Result<()> {