Allow aliasing to the system version (#556)

src/alias.rs

@@ -1,5 +1,6 @@
 use crate::config::FnmConfig;
-use crate::fs::{remove_symlink_dir, symlink_dir};
+use crate::fs::{remove_symlink_dir, shallow_read_symlink, symlink_dir};
+use crate::system_version;
 use crate::version::Version;
 use std::convert::TryInto;
 use std::path::PathBuf;
@@ -12,15 +13,10 @@ pub fn create_alias(
     let aliases_dir = config.aliases_dir();
     std::fs::create_dir_all(&aliases_dir)?;
 
-    let version_dir = version
-        .installation_path(config)
-        .ok_or_else(|| std::io::Error::from(std::io::ErrorKind::NotFound))?;
+    let version_dir = version.installation_path(config);
     let alias_dir = aliases_dir.join(common_name);
 
-    if alias_dir.exists() {
-        remove_symlink_dir(&alias_dir)?;
-    }
-
+    remove_symlink_dir(&alias_dir).ok();
     symlink_dir(&version_dir, &alias_dir)?;
 
     Ok(())
@@ -44,7 +40,12 @@ impl std::convert::TryInto<StoredAlias> for &std::path::Path {
     type Error = std::io::Error;
 
     fn try_into(self) -> Result<StoredAlias, Self::Error> {
-        let destination_path = std::fs::canonicalize(&self)?;
+        let shallow_self = shallow_read_symlink(self)?;
+        let destination_path = if shallow_self == system_version::path() {
+            shallow_self
+        } else {
+            std::fs::canonicalize(&shallow_self)?
+        };
         Ok(StoredAlias {
             alias_path: PathBuf::from(self),
             destination_path,
@@ -54,13 +55,17 @@ impl std::convert::TryInto<StoredAlias> for &std::path::Path {
 
 impl StoredAlias {
     pub fn s_ver(&self) -> &str {
-        self.destination_path
-            .parent()
-            .unwrap()
-            .file_name()
-            .expect("must have basename")
-            .to_str()
-            .unwrap()
+        if self.destination_path == system_version::path() {
+            system_version::display_name()
+        } else {
+            self.destination_path
+                .parent()
+                .unwrap()
+                .file_name()
+                .expect("must have basename")
+                .to_str()
+                .unwrap()
+        }
     }
 
     pub fn name(&self) -> &str {

src/choose_version_for_user_input.rs

@@ -1,4 +1,5 @@
 use crate::config::FnmConfig;
+use crate::fs;
 use crate::installed_versions;
 use crate::system_version;
 use crate::user_version::UserVersion;
@@ -8,6 +9,7 @@ use log::info;
 use snafu::{ensure, ResultExt, Snafu};
 use std::path::{Path, PathBuf};
 
+#[derive(Debug)]
 pub struct ApplicableVersion {
     path: PathBuf,
     version: Version,
@@ -31,24 +33,40 @@ pub fn choose_version_for_user_input<'a>(
         installed_versions::list(config.installations_dir()).context(VersionListing)?;
 
     let result = if let UserVersion::Full(Version::Bypassed) = requested_version {
-        info!("Bypassing fnm: using {} node", "system".cyan());
+        info!(
+            "Bypassing fnm: using {} node",
+            system_version::display_name().cyan()
+        );
         Some(ApplicableVersion {
             path: system_version::path(),
             version: Version::Bypassed,
         })
     } else if let Some(alias_name) = requested_version.alias_name() {
         let alias_path = config.aliases_dir().join(&alias_name);
-        ensure!(
-            alias_path.exists(),
-            CantFindVersion {
-                requested_version: requested_version.clone()
-            }
-        );
-        info!("Using Node for alias {}", alias_name.cyan());
-        Some(ApplicableVersion {
-            path: alias_path,
-            version: Version::Alias(alias_name),
-        })
+        let system_path = system_version::path();
+        if matches!(fs::shallow_read_symlink(&alias_path), Ok(shallow_path) if shallow_path == system_path)
+        {
+            info!(
+                "Bypassing fnm: using {} node",
+                system_version::display_name().cyan()
+            );
+            Some(ApplicableVersion {
+                path: alias_path,
+                version: Version::Bypassed,
+            })
+        } else {
+            ensure!(
+                alias_path.exists(),
+                CantFindVersion {
+                    requested_version: requested_version.clone()
+                }
+            );
+            info!("Using Node for alias {}", alias_name.cyan());
+            Some(ApplicableVersion {
+                path: alias_path,
+                version: Version::Alias(alias_name),
+            })
+        }
     } else {
         let current_version = requested_version.to_version(&all_versions, config);
         current_version.map(|version| {

src/commands/env.rs

@@ -84,6 +84,9 @@ impl Command for Env {
         if self.use_on_cd {
             println!("{}", shell.use_on_cd(config));
         }
+        if let Some(v) = shell.rehash() {
+            println!("{}", v);
+        }
         Ok(())
     }
 }

src/commands/unalias.rs

@@ -1,7 +1,9 @@
 use super::command::Command;
-use crate::config::FnmConfig;
 use crate::fs::remove_symlink_dir;
-use snafu::{ensure, ResultExt, Snafu};
+use crate::user_version::UserVersion;
+use crate::version::Version;
+use crate::{choose_version_for_user_input, config::FnmConfig};
+use snafu::{OptionExt, ResultExt, Snafu};
 use structopt::StructOpt;
 
 #[derive(StructOpt, Debug)]
@@ -13,15 +15,17 @@ impl Command for Unalias {
     type Error = Error;
 
     fn apply(self, config: &FnmConfig) -> Result<(), Self::Error> {
-        let alias_path = config.aliases_dir().join(&self.requested_alias);
-        ensure!(
-            alias_path.exists(),
-            AliasNotFound {
-                requested_alias: self.requested_alias
-            }
-        );
+        let requested_version = choose_version_for_user_input::choose_version_for_user_input(
+            &UserVersion::Full(Version::Alias(self.requested_alias.clone())),
+            config,
+        )
+        .ok()
+        .flatten()
+        .with_context(|| AliasNotFound {
+            requested_alias: self.requested_alias,
+        })?;
 
-        remove_symlink_dir(&alias_path).context(CantDeleteSymlink)?;
+        remove_symlink_dir(&requested_version.path()).context(CantDeleteSymlink)?;
 
         Ok(())
     }

src/commands/use.rs

@@ -38,11 +38,16 @@ impl Command for Use {
             .context(CantInferVersion)?;
 
         let version_path = if let UserVersion::Full(Version::Bypassed) = requested_version {
-            outln!(config#Info, "Bypassing fnm: using {} node", "system".cyan());
+            outln!(config#Info, "Bypassing fnm: using {} node", system_version::display_name().cyan());
             system_version::path()
         } else if let Some(alias_name) = requested_version.alias_name() {
             let alias_path = config.aliases_dir().join(&alias_name);
-            if alias_path.exists() {
+            let system_path = system_version::path();
+            if matches!(fs::shallow_read_symlink(&alias_path), Ok(shallow_path) if shallow_path == system_path)
+            {
+                outln!(config#Info, "Bypassing fnm: using {} node", system_version::display_name().cyan());
+                system_path
+            } else if alias_path.exists() {
                 outln!(config#Info, "Using Node for alias {}", alias_name.cyan());
                 alias_path
             } else {
@@ -164,6 +169,8 @@ fn warn_if_multishell_path_not_in_path_env_var(
 pub enum Error {
     #[snafu(display("Can't create the symlink: {}", source))]
     SymlinkingCreationIssue { source: std::io::Error },
+    #[snafu(display("Can't read the symlink: {}", source))]
+    SymlinkReadFailed { source: std::io::Error },
     #[snafu(display("{}", source))]
     InstallError { source: <Install as Command>::Error },
     #[snafu(display("Can't get locally installed versions: {}", source))]

src/fs.rs

@@ -23,3 +23,7 @@ pub fn remove_symlink_dir<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
     std::fs::remove_file(path)?;
     Ok(())
 }
+
+pub fn shallow_read_symlink<P: AsRef<Path>>(path: P) -> std::io::Result<std::path::PathBuf> {
+    std::fs::read_link(path)
+}

src/shell/shell.rs

@@ -5,6 +5,9 @@ pub trait Shell: Debug {
     fn path(&self, path: &Path) -> String;
     fn set_env_var(&self, name: &str, value: &str) -> String;
     fn use_on_cd(&self, config: &crate::config::FnmConfig) -> String;
+    fn rehash(&self) -> Option<String> {
+        None
+    }
     fn to_structopt_shell(&self) -> structopt::clap::Shell;
 }
 

src/shell/zsh.rs

@@ -18,6 +18,10 @@ impl Shell for Zsh {
         format!("export {}={:?}", name, value)
     }
 
+    fn rehash(&self) -> Option<String> {
+        Some("rehash".to_string())
+    }
+
     fn use_on_cd(&self, _config: &crate::config::FnmConfig) -> String {
         indoc!(
             r#"

src/system_version.rs

@@ -9,3 +9,7 @@ pub fn path() -> PathBuf {
 
     PathBuf::from(path_as_string)
 }
+
+pub fn display_name() -> &'static str {
+    "system"
+}

src/version.rs

@@ -1,6 +1,7 @@
 use crate::alias;
 use crate::config;
 use crate::lts::LtsType;
+use crate::system_version;
 use std::str::FromStr;
 
 #[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone)]
@@ -18,7 +19,7 @@ fn first_letter_is_number(s: &str) -> bool {
 impl Version {
     pub fn parse<S: AsRef<str>>(version_str: S) -> Result<Self, semver::Error> {
         let lowercased = version_str.as_ref().to_lowercase();
-        if lowercased == "system" {
+        if lowercased == system_version::display_name() {
             Ok(Self::Bypassed)
         } else if lowercased.starts_with("lts-") || lowercased.starts_with("lts/") {
             let lts_type = LtsType::from(&lowercased[4..]);
@@ -54,30 +55,24 @@ impl Version {
         format!("{}", self)
     }
 
-    pub fn installation_path(&self, config: &config::FnmConfig) -> Option<std::path::PathBuf> {
+    pub fn installation_path(&self, config: &config::FnmConfig) -> std::path::PathBuf {
         match self {
-            Self::Bypassed => None,
+            Self::Bypassed => system_version::path(),
             v @ (Self::Lts(_) | Self::Alias(_)) => {
-                Some(config.aliases_dir().join(v.alias_name().unwrap()))
+                config.aliases_dir().join(v.alias_name().unwrap())
             }
-            v @ Self::Semver(_) => Some(
-                config
-                    .installations_dir()
-                    .join(v.v_str())
-                    .join("installation"),
-            ),
+            v @ Self::Semver(_) => config
+                .installations_dir()
+                .join(v.v_str())
+                .join("installation"),
         }
     }
 
     pub fn root_path(&self, config: &config::FnmConfig) -> Option<std::path::PathBuf> {
-        match self.installation_path(config) {
-            None => None,
-            Some(path) => {
-                let mut canon_path = path.canonicalize().ok()?;
-                canon_path.pop();
-                Some(canon_path)
-            }
-        }
+        let path = self.installation_path(config);
+        let mut canon_path = path.canonicalize().ok()?;
+        canon_path.pop();
+        Some(canon_path)
     }
 }
 
@@ -94,7 +89,7 @@ impl<'de> serde::Deserialize<'de> for Version {
 impl std::fmt::Display for Version {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::Bypassed => write!(f, "system"),
+            Self::Bypassed => write!(f, "{}", system_version::display_name()),
             Self::Lts(lts) => write!(f, "lts-{}", lts),
             Self::Semver(semver) => write!(f, "v{}", semver),
             Self::Alias(alias) => write!(f, "{}", alias),

tests/feature_tests/mod.rs

@@ -238,3 +238,17 @@ mod unalias_error {
             .then(OutputContains::new(IgnoreErrors::new(GetStderr::new(Call::new("fnm", vec!["unalias", "lts"]))),  "Requested alias lts not found"))
     });
 }
+
+mod alias_system {
+    test_shell!(Bash, Zsh, Fish, PowerShell; {
+        EvalFnmEnv::default()
+            .then(Call::new("fnm", vec!["alias", "system", "my_system"]))
+            .then(OutputContains::new(Call::new("fnm", vec!["ls"]), "my_system"))
+            .then(Call::new("fnm", vec!["alias", "system", "default"]))
+            .then(Call::new("fnm", vec!["alias", "my_system", "my_system2"]))
+            .then(OutputContains::new(Call::new("fnm", vec!["ls"]), "my_system2"))
+            .then(OutputContains::new(Call::new("fnm", vec!["use", "my_system"]), "Bypassing fnm"))
+            .then(Call::new("fnm", vec!["unalias", "my_system"]))
+            .then(OutputContains::new(IgnoreErrors::new(GetStderr::new(Call::new("fnm", vec!["use", "my_system"]))),  "Requested version my_system is not currently installed"))
+    });
+}

tests/feature_tests/snapshots/e2e__feature_tests__alias_system__Bash.snap

@@ -0,0 +1,17 @@
+---
+source: tests/feature_tests/mod.rs
+expression: "&source.trim()"
+
+---
+set -e
+shopt -s expand_aliases
+
+eval "$(fnm env)"
+fnm alias system my_system
+fnm ls | grep my_system
+fnm alias system default
+fnm alias my_system my_system2
+fnm ls | grep my_system2
+fnm use my_system | grep 'Bypassing fnm'
+fnm unalias my_system
+fnm use my_system 2>&1 | grep 'Requested version my_system is not currently installed'

tests/feature_tests/snapshots/e2e__feature_tests__alias_system__Fish.snap

@@ -0,0 +1,14 @@
+---
+source: tests/feature_tests/mod.rs
+expression: "&source.trim()"
+
+---
+fnm env | source
+fnm alias system my_system
+fnm ls | grep my_system
+fnm alias system default
+fnm alias my_system my_system2
+fnm ls | grep my_system2
+fnm use my_system | grep 'Bypassing fnm'
+fnm unalias my_system
+fnm use my_system 2>&1 | grep 'Requested version my_system is not currently installed'

tests/feature_tests/snapshots/e2e__feature_tests__alias_system__PowerShell.snap

@@ -0,0 +1,15 @@
+---
+source: tests/feature_tests/mod.rs
+expression: "&source.trim()"
+
+---
+$ErrorActionPreference = "Stop"
+fnm env | Out-String | Invoke-Expression
+fnm alias system my_system
+$($__out__ = $(fnm ls | Select-String 'my_system'); echo $__out__; if ($__out__ -eq $null){ exit 1 } else { $__out__ })
+fnm alias system default
+fnm alias my_system my_system2
+$($__out__ = $(fnm ls | Select-String 'my_system2'); echo $__out__; if ($__out__ -eq $null){ exit 1 } else { $__out__ })
+$($__out__ = $(fnm use my_system | Select-String 'Bypassing fnm'); echo $__out__; if ($__out__ -eq $null){ exit 1 } else { $__out__ })
+fnm unalias my_system
+$($__out__ = $($($_tmp_err_action = $ErrorActionPreference;$ErrorActionPreference = "Continue";fnm use my_system 2>&1;$ErrorActionPreference = $_tmp_err_action) | Select-String 'Requested version my_system is not currently installed'); echo $__out__; if ($__out__ -eq $null){ exit 1 } else { $__out__ })

tests/feature_tests/snapshots/e2e__feature_tests__alias_system__Zsh.snap

@@ -0,0 +1,15 @@
+---
+source: tests/feature_tests/mod.rs
+expression: "&source.trim()"
+
+---
+set -e
+eval "$(fnm env)"
+fnm alias system my_system
+fnm ls | grep my_system
+fnm alias system default
+fnm alias my_system my_system2
+fnm ls | grep my_system2
+fnm use my_system | grep 'Bypassing fnm'
+fnm unalias my_system
+fnm use my_system 2>&1 | grep 'Requested version my_system is not currently installed'