Add set export to export all variables as environment variables (#767)

Add a setting that exports all variables by default, regardless of
whether they use the `export` keyword. This includes assignments as well
as parameters.

Just does dependency analysis of variable uses, allowing variables to be
used out of order in assignments, as long as there are no circular
dependencies.

However, use of environment variable is not known to Just, so exported
variables are only exported to child scopes, to avoid ordering dependencies,
since dependency analysis cannot be done.

GRAMMAR.md

@@ -55,7 +55,8 @@ assignment    : NAME ':=' expression eol
 
 export        : 'export' assignment
 
-setting       : 'set' 'shell' ':=' '[' string (',' string)* ','? ']'
+setting       : 'set' 'export'
+              | 'set' 'shell' ':=' '[' string (',' string)* ','? ']'
 
 expression    : 'if' condition '{' expression '}' else '{' expression '}'
               | value '+' expression

README.adoc

@@ -388,6 +388,7 @@ foo:
 [options="header"]
 |=================
 | Name | Value | Description
+| `export` | | Export all variables as environment variables
 |`shell` | `[COMMAND, ARGS...]` | Set the command used to invoke recipes and evaluate backticks.
 |=================
 
@@ -407,6 +408,26 @@ foo:
   print("{{foos}}")
 ```
 
+==== Export
+
+The `export` setting causes all Just variables to be exported as environment variables.
+
+```make
+set export
+
+a := "hello"
+
+@foo b:
+  echo $a
+  echo $b
+```
+
+```
+$ just foo goodbye
+hello
+goodbye
+```
+
 === Documentation Comments
 
 Comments immediately preceding a recipe will appear in `just --list`:

src/analyzer.rs

@@ -69,6 +69,9 @@ impl<'src> Analyzer<'src> {
           assert!(settings.shell.is_none());
           settings.shell = Some(shell);
         },
+        Setting::Export => {
+          settings.export = true;
+        },
       }
     }
 

src/command_ext.rs

@@ -1,29 +1,29 @@
 use crate::common::*;
 
 pub(crate) trait CommandExt {
-  fn export(&mut self, dotenv: &BTreeMap<String, String>, scope: &Scope);
+  fn export(&mut self, settings: &Settings, dotenv: &BTreeMap<String, String>, scope: &Scope);
 
-  fn export_scope(&mut self, scope: &Scope);
+  fn export_scope(&mut self, settings: &Settings, scope: &Scope);
 }
 
 impl CommandExt for Command {
-  fn export(&mut self, dotenv: &BTreeMap<String, String>, scope: &Scope) {
+  fn export(&mut self, settings: &Settings, dotenv: &BTreeMap<String, String>, scope: &Scope) {
     for (name, value) in dotenv {
       self.env(name, value);
     }
 
     if let Some(parent) = scope.parent() {
-      self.export_scope(parent);
+      self.export_scope(settings, parent);
     }
   }
 
-  fn export_scope(&mut self, scope: &Scope) {
+  fn export_scope(&mut self, settings: &Settings, scope: &Scope) {
     if let Some(parent) = scope.parent() {
-      self.export_scope(parent);
+      self.export_scope(settings, parent);
     }
 
     for binding in scope.bindings() {
-      if binding.export {
+      if settings.export || binding.export {
         self.env(binding.name.lexeme(), &binding.value);
       }
     }

src/evaluator.rs

@@ -143,7 +143,7 @@ impl<'src, 'run> Evaluator<'src, 'run> {
 
     cmd.current_dir(&self.search.working_directory);
 
-    cmd.export(self.dotenv, &self.scope);
+    cmd.export(self.settings, self.dotenv, &self.scope);
 
     cmd.stdin(process::Stdio::inherit());
 
@@ -197,14 +197,14 @@ impl<'src, 'run> Evaluator<'src, 'run> {
   ) -> RunResult<'src, Scope<'src, 'run>> {
     let mut evaluator = Evaluator {
       assignments: None,
-      scope: Scope::child(scope),
+      scope: scope.child(),
       search,
       settings,
       dotenv,
       config,
     };
 
-    let mut scope = Scope::child(scope);
+    let mut scope = scope.child();
 
     let mut rest = arguments;
     for parameter in parameters {

src/justfile.rs

@@ -221,7 +221,7 @@ impl<'src> Justfile<'src> {
     search: &'run Search,
     ran: &mut BTreeSet<Vec<String>>,
   ) -> RunResult<'src, ()> {
-    let scope = Evaluator::evaluate_parameters(
+    let outer = Evaluator::evaluate_parameters(
       context.config,
       dotenv,
       &recipe.parameters,
@@ -231,6 +231,8 @@ impl<'src> Justfile<'src> {
       search,
     )?;
 
+    let scope = outer.child();
+
     let mut evaluator =
       Evaluator::recipe_evaluator(context.config, dotenv, &scope, context.settings, search);
 
@@ -251,7 +253,7 @@ impl<'src> Justfile<'src> {
       }
     }
 
-    recipe.run(context, dotenv, scope, search)?;
+    recipe.run(context, dotenv, scope.child(), search)?;
 
     let mut invocation = vec![recipe.name().to_owned()];
     for argument in arguments.iter().cloned() {

src/node.rs

@@ -197,6 +197,7 @@ impl<'src> Node<'src> for Set<'src> {
           set.push_mut(Tree::string(&argument.cooked));
         }
       },
+      Export => {},
     }
 
     set

src/parser.rs

@@ -345,7 +345,9 @@ impl<'tokens, 'src> Parser<'tokens, 'src> {
               items.push(Item::Recipe(self.parse_recipe(doc, false)?));
             },
           Some(Keyword::Set) =>
-            if self.next_are(&[Identifier, Identifier, ColonEquals]) {
+            if self.next_are(&[Identifier, Identifier, ColonEquals])
+              || self.next_are(&[Identifier, Identifier, Eol])
+            {
               items.push(Item::Set(self.parse_set()?));
             } else {
               items.push(Item::Recipe(self.parse_recipe(doc, false)?));
@@ -677,6 +679,14 @@ impl<'tokens, 'src> Parser<'tokens, 'src> {
   fn parse_set(&mut self) -> CompilationResult<'src, Set<'src>> {
     self.presume_keyword(Keyword::Set)?;
     let name = Name::from_identifier(self.presume(Identifier)?);
+
+    if name.lexeme() == Keyword::Export.lexeme() {
+      return Ok(Set {
+        value: Setting::Export,
+        name,
+      });
+    }
+
     self.presume(ColonEquals)?;
     if name.lexeme() == Keyword::Shell.lexeme() {
       self.expect(BracketL)?;

src/recipe.rs

@@ -176,7 +176,7 @@ impl<'src, D> Recipe<'src, D> {
         output_error,
       })?;
 
-      command.export(dotenv, &scope);
+      command.export(context.settings, dotenv, &scope);
 
       // run it!
       match InterruptHandler::guard(|| command.status()) {
@@ -265,7 +265,7 @@ impl<'src, D> Recipe<'src, D> {
           cmd.stdout(Stdio::null());
         }
 
-        cmd.export(dotenv, &scope);
+        cmd.export(context.settings, dotenv, &scope);
 
         match InterruptHandler::guard(|| cmd.status()) {
           Ok(exit_status) =>

src/scope.rs

@@ -7,9 +7,9 @@ pub(crate) struct Scope<'src: 'run, 'run> {
 }
 
 impl<'src, 'run> Scope<'src, 'run> {
-  pub(crate) fn child(parent: &'run Scope<'src, 'run>) -> Scope<'src, 'run> {
+  pub(crate) fn child(&'run self) -> Scope<'src, 'run> {
     Scope {
-      parent:   Some(parent),
+      parent:   Some(self),
       bindings: Table::new(),
     }
   }

src/setting.rs

@@ -3,6 +3,7 @@ use crate::common::*;
 #[derive(Debug)]
 pub(crate) enum Setting<'src> {
   Shell(Shell<'src>),
+  Export,
 }
 
 #[derive(Debug, PartialEq)]

src/settings.rs

@@ -3,11 +3,15 @@ use crate::common::*;
 #[derive(Debug, PartialEq)]
 pub(crate) struct Settings<'src> {
   pub(crate) shell:  Option<setting::Shell<'src>>,
+  pub(crate) export: bool,
 }
 
 impl<'src> Settings<'src> {
   pub(crate) fn new() -> Settings<'src> {
-    Settings { shell: None }
+    Settings {
+      shell:  None,
+      export: false,
+    }
   }
 
   pub(crate) fn shell_command(&self, config: &Config) -> Command {

tests/export.rs

@@ -0,0 +1,122 @@
+test! {
+  name:     success,
+  justfile: r#"
+export FOO := "a"
+baz := "c"
+export BAR := "b"
+export ABC := FOO + BAR + baz
+
+wut:
+  echo $FOO $BAR $ABC
+"#,
+  stdout:   "a b abc\n",
+  stderr:   "echo $FOO $BAR $ABC\n",
+}
+
+test! {
+  name:     override_variable,
+  justfile: r#"
+export FOO := "a"
+baz := "c"
+export BAR := "b"
+export ABC := FOO + "-" + BAR + "-" + baz
+
+wut:
+  echo $FOO $BAR $ABC
+"#,
+  args:     ("--set", "BAR", "bye", "FOO=hello"),
+  stdout:   "hello bye hello-bye-c\n",
+  stderr:   "echo $FOO $BAR $ABC\n",
+}
+
+test! {
+  name:     shebang,
+  justfile: r#"
+export FOO := "a"
+baz := "c"
+export BAR := "b"
+export ABC := FOO + BAR + baz
+
+wut:
+  #!/bin/sh
+  echo $FOO $BAR $ABC
+"#,
+  stdout:   "a b abc\n",
+}
+
+test! {
+  name:     recipe_backtick,
+  justfile: r#"
+export EXPORTED_VARIABLE := "A-IS-A"
+
+recipe:
+  echo {{`echo recipe $EXPORTED_VARIABLE`}}
+"#,
+  stdout:   "recipe A-IS-A\n",
+  stderr:   "echo recipe A-IS-A\n",
+}
+
+test! {
+  name: setting,
+  justfile: "
+    set export
+
+    A := 'hello'
+
+    foo B C=`echo $A`:
+      echo $A
+      echo $B
+      echo $C
+  ",
+  args: ("foo", "goodbye"),
+  stdout: "hello\ngoodbye\nhello\n",
+  stderr: "echo $A\necho $B\necho $C\n",
+}
+
+test! {
+  name: setting_shebang,
+  justfile: "
+    set export
+
+    A := 'hello'
+
+    foo B:
+      #!/bin/sh
+      echo $A
+      echo $B
+  ",
+  args: ("foo", "goodbye"),
+  stdout: "hello\ngoodbye\n",
+  stderr: "",
+}
+
+test! {
+  name: setting_override_undefined,
+  justfile: r#"
+    set export
+
+    A := 'hello'
+    B := `if [ -n "${A+1}" ]; then echo defined; else echo undefined; fi`
+
+    foo C='goodbye' D=`if [ -n "${C+1}" ]; then echo defined; else echo undefined; fi`:
+      echo $B
+      echo $D
+  "#,
+  args: ("A=zzz", "foo"),
+  stdout: "undefined\nundefined\n",
+  stderr: "echo $B\necho $D\n",
+}
+
+test! {
+  name: setting_variable_not_visible,
+  justfile: r#"
+    export A := 'hello'
+    export B := `if [ -n "${A+1}" ]; then echo defined; else echo undefined; fi`
+
+    foo:
+      echo $B
+  "#,
+  args: ("A=zzz"),
+  stdout: "undefined\n",
+  stderr: "echo $B\n",
+}

tests/lib.rs

@@ -11,6 +11,7 @@ mod dotenv;
 mod edit;
 mod error_messages;
 mod examples;
+mod export;
 mod init;
 mod interrupts;
 mod invocation_directory;

tests/misc.rs

@@ -574,64 +574,6 @@ hello := "c"
 "#,
 }
 
-test! {
-  name:     export_success,
-  justfile: r#"
-export FOO := "a"
-baz := "c"
-export BAR := "b"
-export ABC := FOO + BAR + baz
-
-wut:
-  echo $FOO $BAR $ABC
-"#,
-  stdout:   "a b abc\n",
-  stderr:   "echo $FOO $BAR $ABC\n",
-}
-
-test! {
-  name:     export_override,
-  justfile: r#"
-export FOO := "a"
-baz := "c"
-export BAR := "b"
-export ABC := FOO + "-" + BAR + "-" + baz
-
-wut:
-  echo $FOO $BAR $ABC
-"#,
-  args:     ("--set", "BAR", "bye", "FOO=hello"),
-  stdout:   "hello bye hello-bye-c\n",
-  stderr:   "echo $FOO $BAR $ABC\n",
-}
-
-test! {
-  name:     export_shebang,
-  justfile: r#"
-export FOO := "a"
-baz := "c"
-export BAR := "b"
-export ABC := FOO + BAR + baz
-
-wut:
-  #!/bin/sh
-  echo $FOO $BAR $ABC
-"#,
-  stdout:   "a b abc\n",
-}
-
-test! {
-  name:     export_recipe_backtick,
-  justfile: r#"
-export EXPORTED_VARIABLE := "A-IS-A"
-
-recipe:
-  echo {{`echo recipe $EXPORTED_VARIABLE`}}
-"#,
-  stdout:   "recipe A-IS-A\n",
-  stderr:   "echo recipe A-IS-A\n",
-}
-
 test! {
   name:     raw_string,
   justfile: r#"