Support defining external justfile locations through env var

Cargo.toml

@@ -40,6 +40,7 @@ semver = "1.0.20"
 serde = { version = "1.0.130", features = ["derive", "rc"] }
 serde_json = "1.0.68"
 sha2 = "0.10"
+shellexpand = "3.1.0"
 similar = { version = "2.1.0", features = ["unicode"] }
 snafu = "0.8.0"
 strum = { version = "0.26.0", features = ["derive"] }

README.md

@@ -2759,7 +2759,8 @@ A
 
 The `import` path can be absolute or relative to the location of the justfile
 containing it. A leading `~/` in the import path is replaced with the current
-users home directory.
+users home directory. Any variable used in the import path is replaced with
+the value of an environment variable of the same name.
 
 Justfiles are insensitive to order, so included files can reference variables
 and recipes defined after the `import` statement.
@@ -2831,7 +2832,8 @@ mod foo 'PATH'
 
 Which loads the module's source file from `PATH`, instead of from the usual
 locations. A leading `~/` in `PATH` is replaced with the current user's home
-directory.
+directory. Any variable used in `PATH` is replaced with the value of an
+environment variable of the same name.
 
 Environment files are only loaded for the root justfile, and loaded environment
 variables are available in submodules. Settings in submodules that affect

src/compiler.rs

@@ -1,4 +1,7 @@
-use super::*;
+use {
+  super::*,
+  shellexpand::full,
+};
 
 pub(crate) struct Compiler;
 
@@ -48,7 +51,9 @@ impl Compiler {
             let parent = current.path.parent().unwrap();
 
             let import = if let Some(relative) = relative {
-              let path = parent.join(Self::expand_tilde(&relative.cooked)?);
+              let expanded_path = full(&relative.cooked).map_err(|error| Error::UnresolvedVariableInModule { variable: error.var_name, module: *name })?;
+
+              let path = parent.join(&*expanded_path);
 
               if path.is_file() {
                 Some(path)
@@ -78,11 +83,13 @@ impl Compiler {
             optional,
             path,
           } => {
+            let expanded_path = full(&relative.cooked).map_err(|error| Error::UnresolvedVariableInImport { variable: error.var_name, path: *path })?;
+
             let import = current
               .path
               .parent()
               .unwrap()
-              .join(Self::expand_tilde(&relative.cooked)?)
+              .join(&*expanded_path)
               .lexiclean();
 
             if import.is_file() {
@@ -155,16 +162,6 @@ impl Compiler {
     }
   }
 
-  fn expand_tilde(path: &str) -> RunResult<'static, PathBuf> {
-    Ok(if let Some(path) = path.strip_prefix("~/") {
-      dirs::home_dir()
-        .ok_or(Error::Homedir)?
-        .join(path.trim_start_matches('/'))
-    } else {
-      PathBuf::from(path)
-    })
-  }
-
   #[cfg(test)]
   pub(crate) fn test_compile(src: &str) -> CompileResult<Justfile> {
     let tokens = Lexer::test_lex(src)?;

src/error.rs

@@ -98,7 +98,6 @@ pub(crate) enum Error<'src> {
   GetConfirmation {
     io_error: io::Error,
   },
-  Homedir,
   InitExists {
     justfile: PathBuf,
   },
@@ -160,6 +159,14 @@ pub(crate) enum Error<'src> {
     recipes: Vec<String>,
     suggestion: Option<Suggestion<'src>>,
   },
+  UnresolvedVariableInImport {
+    variable: String,
+    path: Token<'src>,
+  },
+  UnresolvedVariableInModule {
+    variable: String,
+    module: Name<'src>,
+  },
   Unstable {
     message: String,
   },
@@ -191,6 +198,8 @@ impl<'src> Error<'src> {
       Self::Compile { compile_error } => Some(compile_error.context()),
       Self::FunctionCall { function, .. } => Some(function.token),
       Self::MissingImportFile { path } => Some(*path),
+      Self::UnresolvedVariableInImport { variable: _, path } => Some(*path),
+      Self::UnresolvedVariableInModule { variable: _, module } => Some(module.token),
       _ => None,
     }
   }
@@ -361,9 +370,6 @@ impl<'src> ColorDisplay for Error<'src> {
       GetConfirmation { io_error } => {
         write!(f, "Failed to read confirmation from stdin: {io_error}")?;
       }
-      Homedir => {
-        write!(f, "Failed to get homedir")?;
-      }
       InitExists { justfile } => {
         write!(f, "Justfile `{}` already exists", justfile.display())?;
       }
@@ -433,6 +439,8 @@ impl<'src> ColorDisplay for Error<'src> {
           write!(f, "\n{suggestion}")?;
         }
       }
+      UnresolvedVariableInImport { variable, .. } => write!(f, "Path to file contains unresolved variable {variable}.")?,
+      UnresolvedVariableInModule { variable, module } => write!(f, "Source path for {module} contains unresolved variable {variable}.")?,
       Unstable { message } => {
         write!(f, "{message} Invoke `just` with the `--unstable` flag to enable unstable features.")?;
       }

tests/imports.rs

@@ -224,7 +224,7 @@ fn variables_in_import_are_overridden_by_variables_in_parent() {
 
 #[cfg(not(windows))]
 #[test]
-fn import_paths_beginning_with_tilde_are_expanded_to_homdir() {
+fn import_paths_beginning_with_tilde_are_expanded_to_homedir() {
   Test::new()
     .write("foobar/mod.just", "foo:\n @echo FOOBAR")
     .justfile(
@@ -239,6 +239,48 @@ fn import_paths_beginning_with_tilde_are_expanded_to_homdir() {
     .run();
 }
 
+#[test]
+fn import_paths_with_variables_are_expanded() {
+  Test::new()
+    .write("foobar/mod.just", "foo:\n @echo FOOBAR")
+    .justfile(
+      "
+        import '$FOO/mod.just'
+      ",
+    )
+    .test_round_trip(false)
+    .arg("foo")
+    .stdout("FOOBAR\n")
+    .env("FOO", "foobar")
+    .run();
+}
+
+#[test]
+fn unresolved_variable_in_import_error() {
+  Test::new()
+    .justfile(
+      "
+        import '$FOO/import.justfile'
+
+        a:
+          @echo A
+      ",
+    )
+    .test_round_trip(false)
+    .arg("a")
+    .status(EXIT_FAILURE)
+    .stderr(
+      "
+      error: Path to file contains unresolved variable FOO.
+       ——▶ justfile:1:8
+        │
+      1 │ import '$FOO/import.justfile'
+        │        ^^^^^^^^^^^^^^^^^^^^^^
+      ",
+    )
+    .run();
+}
+
 #[test]
 fn imports_dump_correctly() {
   Test::new()

tests/modules.rs

@@ -678,7 +678,7 @@ fn submodule_shebang_recipes_run_in_submodule_directory() {
 
 #[cfg(not(windows))]
 #[test]
-fn module_paths_beginning_with_tilde_are_expanded_to_homdir() {
+fn module_paths_beginning_with_tilde_are_expanded_to_homedir() {
   Test::new()
     .write("foobar/mod.just", "foo:\n @echo FOOBAR")
     .justfile(
@@ -695,6 +695,47 @@ fn module_paths_beginning_with_tilde_are_expanded_to_homdir() {
     .run();
 }
 
+#[test]
+fn module_paths_with_variables_are_expanded() {
+  Test::new()
+    .write("foobar/mod.just", "foo:\n @echo FOOBAR")
+    .justfile(
+      "
+        mod foo '$FOO/mod.just'
+      ",
+    )
+    .test_round_trip(false)
+    .arg("--unstable")
+    .arg("foo")
+    .arg("foo")
+    .stdout("FOOBAR\n")
+    .env("FOO", "foobar")
+    .run();
+}
+
+#[test]
+fn unresolved_variable_in_module_error() {
+  Test::new()
+    .justfile(
+      "
+        mod foo '$FOO/mod.just'
+      ",
+    )
+    .test_round_trip(false)
+    .arg("--unstable")
+    .status(EXIT_FAILURE)
+    .stderr(
+      "
+      error: Source path for foo contains unresolved variable FOO.
+       ——▶ justfile:1:5
+        │
+      1 │ mod foo '$FOO/mod.just'
+        │     ^^^
+      ",
+    )
+    .run();
+}
+
 #[test]
 fn module_recipe_list_alignment_ignores_private_recipes() {
   Test::new()