fix: do not resolve toolchains from files with --no-net (#145)

src/elan/config.rs

@@ -17,7 +17,7 @@ use toolchain::Toolchain;
 
 use toml;
 
-use crate::{gc, lookup_toolchain_desc, lookup_unresolved_toolchain_desc, read_toolchain_desc_from_file, UnresolvedToolchainDesc};
+use crate::{gc, lookup_toolchain_desc, lookup_unresolved_toolchain_desc, read_unresolved_toolchain_desc_from_file, UnresolvedToolchainDesc};
 
 #[derive(Debug, Serialize, Clone)]
 pub enum OverrideReason {
@@ -186,10 +186,10 @@ impl Cfg {
 
             // Then look for 'lean-toolchain'
             let toolchain_file = d.join("lean-toolchain");
-            if let Ok(desc) = read_toolchain_desc_from_file(self, &toolchain_file) {
+            if let Ok(desc) = read_unresolved_toolchain_desc_from_file(self, &toolchain_file) {
                 let reason = OverrideReason::ToolchainFile(toolchain_file);
                 gc::add_root(self, d)?;
-                return Ok(Some((UnresolvedToolchainDesc(desc), reason)));
+                return Ok(Some((desc, reason)));
             }
 
             // Then look for 'leanpkg.toml'

src/elan/toolchain.rs

@@ -103,16 +103,20 @@ pub fn lookup_toolchain_desc(cfg: &Cfg, name: &str) -> Result<ToolchainDesc> {
     resolve_toolchain_desc(cfg, &lookup_unresolved_toolchain_desc(cfg, name)?, false)
 }
 
-pub fn read_toolchain_desc_from_file(cfg: &Cfg, toolchain_file: &Path) -> Result<ToolchainDesc> {
+pub fn read_unresolved_toolchain_desc_from_file(cfg: &Cfg, toolchain_file: &Path) -> Result<UnresolvedToolchainDesc> {
     let s = utils::read_file("toolchain file", &toolchain_file)?;
     if let Some(s) = s.lines().next() {
         let toolchain_name = s.trim();
-        lookup_toolchain_desc(cfg, toolchain_name)
+        lookup_unresolved_toolchain_desc(cfg, toolchain_name)
     } else {
         Err(Error::from(format!("empty toolchain file '{}'", toolchain_file.display())))
     }
 }
 
+pub fn read_toolchain_desc_from_file(cfg: &Cfg, toolchain_file: &Path) -> Result<ToolchainDesc> {
+    resolve_toolchain_desc(cfg, &read_unresolved_toolchain_desc_from_file(cfg, toolchain_file)?, false)
+}
+
 impl<'a> Toolchain<'a> {
     pub fn from(cfg: &'a Cfg, desc: &ToolchainDesc) -> Self {
         //We need to replace ":" and "/" with "-" in the toolchain name in order to make a name which is a valid