fix: conflicted error msg

core/src/ten_manager/src/cmd/cmd_install.rs

@@ -282,12 +282,16 @@ fn write_pkgs_into_lock(pkgs: &Vec<&PkgInfo>, app_dir: &Path) -> Result<()> {
 
 fn parse_pkg_name_version(
     pkg_name_version: &str,
-) -> Result<(String, VersionReq)> {
+) -> Result<(String, Option<String>, VersionReq)> {
     let parts: Vec<&str> = pkg_name_version.split('@').collect();
     if parts.len() == 2 {
-        Ok((parts[0].to_string(), VersionReq::parse(parts[1])?))
+        Ok((
+            parts[0].to_string(),
+            Some(parts[1].to_string()),
+            VersionReq::parse(parts[1])?,
+        ))
     } else {
-        Ok((pkg_name_version.to_string(), VersionReq::STAR))
+        Ok((pkg_name_version.to_string(), None, VersionReq::STAR))
     }
 }
 
@@ -499,8 +503,11 @@ pub async fn execute_cmd(
         // Case 1: tman install <package_type> <package_name>
 
         let desired_pkg_type_: PkgType = package_type_str.parse()?;
-        let (desired_pkg_src_name_, desired_pkg_src_version_) =
-            parse_pkg_name_version(&command_data.package_name.unwrap())?;
+        let (
+            desired_pkg_src_name_,
+            desired_pkg_src_version_str_,
+            desired_pkg_src_version_,
+        ) = parse_pkg_name_version(&command_data.package_name.unwrap())?;
 
         desired_pkg_type = Some(desired_pkg_type_.clone());
         desired_pkg_src_name = Some(desired_pkg_src_name_.clone());
@@ -552,6 +559,7 @@ pub async fn execute_cmd(
                         name: desired_pkg_src_name_.clone(),
                     },
                     version_req: desired_pkg_src_version_.clone(),
+                    version_req_str: desired_pkg_src_version_str_,
                 },
             };
             extra_dependency_relationships.push(extra_dependency_relationship);
@@ -853,7 +861,59 @@ do you want to continue?",
 
         Ok(())
     } else {
-        if let Some(non_usable_model) = non_usable_models.first() {
+        // The last model always represents the optimal version.
+        //
+        // The first error messages (i.e., non_usable_models.first()) might be
+        // changed when we run `tman install` in an app folder, if the app
+        // contains a conflicted dependency which has many candidates. The
+        // different error messages are as follows.
+        //
+        // ```
+        // ❌  Error: Select more than 1 version of '[system]ten_runtime':
+        //     '@0.2.0' introduced by '[extension][email protected]', and '@0.3.1'
+        //     introduced by '[system][email protected]'
+        // ```
+        //
+        // ```
+        // ❌  Error: Select more than 1 version of '[system]ten_runtime':
+        //     '@0.2.0' introduced by '[extension][email protected]', and '@0.3.0'
+        //     introduced by '[system][email protected]'
+        // ```
+        //
+        // The introducer pkg are different in the two error messages,
+        // `[email protected]` vs `[email protected]`.
+        //
+        // The reason is that the candidates are stored in a HashSet, and when
+        // they are traversed and written to the `depends_on_declared` field in
+        // `input.lp``, the order of writing is not guaranteed. Ex, the
+        // `agora_rtm` has three candidates, 0.1.0, 0.1.1, 0.1.2. The
+        // content in the input.ip might be:
+        //
+        // case 1:
+        // ```
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.0").
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.1").
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.2").
+        // ```
+        //
+        // or
+        //
+        // case 2:
+        // ```
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.2").
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.0").
+        // depends_on_declared("app", "ten_agent", "0.4.0", "extension", "agora_rtm", "0.1.1").
+        // ```
+        // Due to the different order of input data, clingo may start searching
+        // from different points. However, clingo will only output increasingly
+        // better models. Therefore, if we select the first `non_usable_models`,
+        // it is often inconsistent. But if we select the last model, it is
+        // usually consistent, representing the optimal error model that clingo
+        // can find. This phenomenon is similar to the gradient descent process
+        // in neural networks that seeks local optima. Thus, we should select
+        // the last model to obtain the optimal error model and achieve stable
+        // results.
+        if let Some(non_usable_model) = non_usable_models.last() {
             // Extract introducer relations, and parse the error message.
             if let Ok(conflict_info) = parse_error_statement(non_usable_model) {
                 // Print the error message and dependency chains.

core/src/ten_manager/src/manifest_lock/mod.rs

@@ -253,6 +253,7 @@ impl<'a> From<&'a ManifestLockItem> for PkgInfo {
                                 name: dep.name,
                             },
                             version_req: VersionReq::STAR,
+                            version_req_str: None,
                         })
                         .collect()
                 })

core/src/ten_manager/src/solver/introducer.rs

@@ -13,16 +13,17 @@ use ten_rust::pkg_info::{pkg_identity::PkgIdentity, PkgInfo};
 
 use crate::dep_and_candidate::get_pkg_info_from_candidates;
 
+/// Returns a map from a package to its introducer and the requested version.
 pub fn extract_introducer_relations_from_raw_solver_results(
     results: &[String],
     all_candidates: &HashMap<PkgIdentity, HashSet<PkgInfo>>,
-) -> Result<HashMap<PkgInfo, Option<PkgInfo>>> {
+) -> Result<HashMap<PkgInfo, (String, Option<PkgInfo>)>> {
     let re = Regex::new(
       r#"introducer\("([^"]+)","([^"]+)","([^"]+)","([^"]+)","([^"]*)","([^"]*)"\)"#,
   )
   .unwrap();
 
-    let mut introducer_relations: HashMap<PkgInfo, Option<PkgInfo>> =
+    let mut introducer_relations: HashMap<PkgInfo, (String, Option<PkgInfo>)> =
         HashMap::new();
 
     for result in results.iter() {
@@ -35,6 +36,10 @@ pub fn extract_introducer_relations_from_raw_solver_results(
             let introducer_name = caps.get(5).unwrap().as_str();
             let introducer_version_str = caps.get(6).unwrap().as_str();
 
+            // Using the requested version (i.e., the version field declared in
+            // manifest.json) in the dependency chain is more user-friendly.
+            let mut requested_version_str = version_str.to_string();
+
             let pkg_info = get_pkg_info_from_candidates(
                 pkg_type_str,
                 name,
@@ -52,38 +57,85 @@ pub fn extract_introducer_relations_from_raw_solver_results(
                     all_candidates,
                 )?;
 
+                let requested_dep_in_introducer = introducer_info
+                    .get_dependency_by_type_and_name(pkg_type_str, name);
+                if let Some(requested_dep_in_introducer) =
+                    requested_dep_in_introducer
+                {
+                    // The `version` declared in the `dependencies` section in
+                    // manifest.json is always present.
+                    requested_version_str = requested_dep_in_introducer
+                        .version_req_str
+                        .as_ref()
+                        .unwrap()
+                        .clone();
+                } else {
+                    return Err(anyhow::anyhow!(
+                        "Requested dependency [{}]{} not found in introducer, should not happen.", pkg_type_str, name
+                    ));
+                }
+
                 Some(introducer_info.clone())
             };
 
-            introducer_relations.insert(pkg_info.clone(), introducer);
+            introducer_relations
+                .insert(pkg_info.clone(), (requested_version_str, introducer));
         }
     }
 
     Ok(introducer_relations)
 }
 
 pub fn get_dependency_chain(
-    pkg_info: &PkgInfo,
-    introducer_relations: &HashMap<PkgInfo, Option<PkgInfo>>,
-) -> Vec<PkgInfo> {
+    introducer: &PkgInfo,
+    conflict_pkg_identity: &PkgIdentity,
+    introducer_relations: &HashMap<PkgInfo, (String, Option<PkgInfo>)>,
+) -> Vec<(String, PkgIdentity)> {
     let mut chain = Vec::new();
-    let mut current_pkg = pkg_info.clone();
+    let mut current_pkg = introducer.clone();
     let mut visited = HashSet::new();
 
+    // Add the leaf node (i.e., `introducer` depends on `pkg_name`) to the
+    // dependency chain first.
+    let requested_dep_in_introducer = introducer
+        .get_dependency_by_type_and_name(
+            &conflict_pkg_identity.pkg_type.to_string(),
+            &conflict_pkg_identity.name,
+        )
+        .unwrap();
+    chain.push((
+        requested_dep_in_introducer
+            .version_req_str
+            .as_ref()
+            .unwrap()
+            .clone(),
+        conflict_pkg_identity.clone(),
+    ));
+
     loop {
         if !visited.insert(current_pkg.clone()) {
             // Detected a cycle, break to prevent infinite loop.
             break;
         }
 
-        chain.push(current_pkg.clone());
-
         match introducer_relations.get(&current_pkg) {
-            Some(Some(introducer_pkg)) => {
+            Some((requested_version, Some(introducer_pkg))) => {
+                // The dependency chain is that `introducer_pkg` depends on
+                // `current_pkg`@`requested_version`, i.e., the
+                // `requested_version` is used to declared the `current_pkg` in
+                // the manifest.json of `introducer_pkg`.
+                chain.push((
+                    requested_version.clone(),
+                    current_pkg.pkg_identity.clone(),
+                ));
                 current_pkg = introducer_pkg.clone();
             }
-            Some(None) => {
+            Some((requested_version, None)) => {
                 // Reached the root.
+                chain.push((
+                    requested_version.clone(),
+                    current_pkg.pkg_identity.clone(),
+                ));
                 break;
             }
             None => {