Allow duplicate imports (#2437)

README.md

@@ -3319,7 +3319,33 @@ Imports may be made optional by putting a `?` after the `import` keyword:
 import? 'foo/bar.just'
 ```
 
-Missing source files for optional imports do not produce an error.
+Importing the same source file multiple times is not an error<sup>master</sup>.
+This allows importing multiple justfiles, for example `foo.just` and
+`bar.just`, which both import a third justfile containing shared recipes, for
+example `baz.just`, without the duplicate import of `baz.just` being an error:
+
+```mf
+# justfile
+import 'foo.just'
+import 'bar.just'
+```
+
+```mf
+# foo.just
+import 'baz.just'
+foo: baz
+```
+
+```mf
+# bar.just
+import 'baz.just'
+bar: baz
+```
+
+```just
+# baz
+baz:
+```
 
 ### Modules<sup>1.19.0</sup>
 

src/analyzer.rs

@@ -35,6 +35,7 @@ impl<'run, 'src> Analyzer<'run, 'src> {
     root: &Path,
   ) -> CompileResult<'src, Justfile<'src>> {
     let mut definitions = HashMap::new();
+    let mut imports = HashSet::new();
 
     let mut stack = Vec::new();
     let ast = asts.get(root).unwrap();
@@ -54,7 +55,9 @@ impl<'run, 'src> Analyzer<'run, 'src> {
           Item::Comment(_) => (),
           Item::Import { absolute, .. } => {
             if let Some(absolute) = absolute {
-              stack.push(asts.get(absolute).unwrap());
+              if imports.insert(absolute) {
+                stack.push(asts.get(absolute).unwrap());
+              }
             }
           }
           Item::Module {

src/compiler.rs

@@ -21,7 +21,6 @@ impl Compiler {
       let tokens = Lexer::lex(relative, src)?;
       let mut ast = Parser::parse(
         current.file_depth,
-        &current.path,
         &current.import_offsets,
         &current.namepath,
         &tokens,
@@ -214,14 +213,7 @@ impl Compiler {
   #[cfg(test)]
   pub(crate) fn test_compile(src: &str) -> CompileResult<Justfile> {
     let tokens = Lexer::test_lex(src)?;
-    let ast = Parser::parse(
-      0,
-      &PathBuf::new(),
-      &[],
-      &Namepath::default(),
-      &tokens,
-      &PathBuf::new(),
-    )?;
+    let ast = Parser::parse(0, &[], &Namepath::default(), &tokens, &PathBuf::new())?;
     let root = PathBuf::from("justfile");
     let mut asts: HashMap<PathBuf, Ast> = HashMap::new();
     asts.insert(root.clone(), ast);

src/parser.rs

@@ -26,7 +26,6 @@ use {super::*, TokenKind::*};
 pub(crate) struct Parser<'run, 'src> {
   expected_tokens: BTreeSet<TokenKind>,
   file_depth: u32,
-  file_path: &'run Path,
   import_offsets: Vec<usize>,
   module_namepath: &'run Namepath<'src>,
   next_token: usize,
@@ -39,7 +38,6 @@ impl<'run, 'src> Parser<'run, 'src> {
   /// Parse `tokens` into an `Ast`
   pub(crate) fn parse(
     file_depth: u32,
-    file_path: &'run Path,
     import_offsets: &[usize],
     module_namepath: &'run Namepath<'src>,
     tokens: &'run [Token<'src>],
@@ -48,7 +46,6 @@ impl<'run, 'src> Parser<'run, 'src> {
     Self {
       expected_tokens: BTreeSet::new(),
       file_depth,
-      file_path,
       import_offsets: import_offsets.to_vec(),
       module_namepath,
       next_token: 0,
@@ -910,7 +907,6 @@ impl<'run, 'src> Parser<'run, 'src> {
       dependencies,
       doc,
       file_depth: self.file_depth,
-      file_path: self.file_path.into(),
       import_offsets: self.import_offsets.clone(),
       name,
       namepath: self.module_namepath.join(name),
@@ -1162,15 +1158,8 @@ mod tests {
   fn test(text: &str, want: Tree) {
     let unindented = unindent(text);
     let tokens = Lexer::test_lex(&unindented).expect("lexing failed");
-    let justfile = Parser::parse(
-      0,
-      &PathBuf::new(),
-      &[],
-      &Namepath::default(),
-      &tokens,
-      &PathBuf::new(),
-    )
-    .expect("parsing failed");
+    let justfile = Parser::parse(0, &[], &Namepath::default(), &tokens, &PathBuf::new())
+      .expect("parsing failed");
     let have = justfile.tree();
     if have != want {
       println!("parsed text: {unindented}");
@@ -1208,14 +1197,7 @@ mod tests {
   ) {
     let tokens = Lexer::test_lex(src).expect("Lexing failed in parse test...");
 
-    match Parser::parse(
-      0,
-      &PathBuf::new(),
-      &[],
-      &Namepath::default(),
-      &tokens,
-      &PathBuf::new(),
-    ) {
+    match Parser::parse(0, &[], &Namepath::default(), &tokens, &PathBuf::new()) {
       Ok(_) => panic!("Parsing unexpectedly succeeded"),
       Err(have) => {
         let want = CompileError {

src/recipe.rs

@@ -26,8 +26,6 @@ pub(crate) struct Recipe<'src, D = Dependency<'src>> {
   #[serde(skip)]
   pub(crate) file_depth: u32,
   #[serde(skip)]
-  pub(crate) file_path: PathBuf,
-  #[serde(skip)]
   pub(crate) import_offsets: Vec<usize>,
   pub(crate) name: Name<'src>,
   pub(crate) namepath: Namepath<'src>,

src/testing.rs

@@ -59,15 +59,8 @@ pub(crate) fn analysis_error(
 ) {
   let tokens = Lexer::test_lex(src).expect("Lexing failed in parse test...");
 
-  let ast = Parser::parse(
-    0,
-    &PathBuf::new(),
-    &[],
-    &Namepath::default(),
-    &tokens,
-    &PathBuf::new(),
-  )
-  .expect("Parsing failed in analysis test...");
+  let ast = Parser::parse(0, &[], &Namepath::default(), &tokens, &PathBuf::new())
+    .expect("Parsing failed in analysis test...");
 
   let root = PathBuf::from("justfile");
   let mut asts: HashMap<PathBuf, Ast> = HashMap::new();

src/unresolved_recipe.rs

@@ -50,7 +50,6 @@ impl<'src> UnresolvedRecipe<'src> {
       dependencies,
       doc: self.doc,
       file_depth: self.file_depth,
-      file_path: self.file_path,
       import_offsets: self.import_offsets,
       name: self.name,
       namepath: self.namepath,

tests/imports.rs

@@ -360,3 +360,51 @@ fn reused_import_are_allowed() {
     })
     .run();
 }
+
+#[test]
+fn multiply_imported_items_do_not_conflict() {
+  Test::new()
+    .justfile(
+      "
+      import 'a.just'
+      import 'a.just'
+      foo: bar
+    ",
+    )
+    .write(
+      "a.just",
+      "
+x := 'y'
+
+@bar:
+  echo hello
+",
+    )
+    .stdout("hello\n")
+    .run();
+}
+
+#[test]
+fn nested_multiply_imported_items_do_not_conflict() {
+  Test::new()
+    .justfile(
+      "
+      import 'a.just'
+      import 'b.just'
+      foo: bar
+    ",
+    )
+    .write("a.just", "import 'c.just'")
+    .write("b.just", "import 'c.just'")
+    .write(
+      "c.just",
+      "
+x := 'y'
+
+@bar:
+  echo hello
+",
+    )
+    .stdout("hello\n")
+    .run();
+}