fix(exit): correct exit semantics in various compund statements (#347)

* Adjust several cases of compound commands where the exit shell request wasn't propagated.
* Add a number of compat test cases to confirm broader behavior.

brush-core/src/commands.rs

@@ -547,7 +547,15 @@ pub(crate) async fn invoke_shell_function(
     // Restore positional parameters.
     context.shell.positional_parameters = prior_positional_params;
 
-    Ok(CommandSpawnResult::ImmediateExit(result?.exit_code))
+    // Get the actual execution result from the body of the function.
+    let result = result?;
+
+    // Report back the exit code, and honor any requests to exit the whole shell.
+    Ok(if result.exit_shell {
+        CommandSpawnResult::ExitShell(result.exit_code)
+    } else {
+        CommandSpawnResult::ImmediateExit(result.exit_code)
+    })
 }
 
 pub(crate) async fn invoke_command_in_subshell_and_get_output(

brush-core/src/interp.rs

@@ -193,7 +193,7 @@ impl Execute for ast::CompoundList {
             }
 
             // Check for early return.
-            if result.return_from_function_or_script {
+            if result.exit_shell || result.return_from_function_or_script {
                 break;
             }
 
@@ -525,7 +525,11 @@ impl Execute for ast::CompoundCommand {
             ast::CompoundCommand::Subshell(ast::SubshellCommand(s)) => {
                 // Clone off a new subshell, and run the body of the subshell there.
                 let mut subshell = shell.clone();
-                s.execute(&mut subshell, params).await
+                let subshell_result = s.execute(&mut subshell, params).await?;
+
+                // Preserve the subshell's exit code, but don't honor any of its requests to exit
+                // the shell, break out of loops, etc.
+                Ok(ExecutionResult::new(subshell_result.exit_code))
             }
             ast::CompoundCommand::ForClause(f) => f.execute(shell, params).await,
             ast::CompoundCommand::CaseClause(c) => c.execute(shell, params).await,
@@ -578,7 +582,7 @@ impl Execute for ast::ForClauseCommand {
                 )?;
 
                 result = self.body.0.execute(shell, params).await?;
-                if result.return_from_function_or_script {
+                if result.exit_shell || result.return_from_function_or_script {
                     break;
                 }
 
@@ -721,16 +725,20 @@ impl Execute for (WhileOrUntil, &ast::WhileOrUntilClauseCommand) {
         loop {
             let condition_result = test_condition.execute(shell, params).await?;
 
-            if condition_result.is_success() != is_while {
+            if condition_result.exit_shell || condition_result.return_from_function_or_script {
+                result.exit_code = condition_result.exit_code;
+                result.exit_shell = condition_result.exit_shell;
+                result.return_from_function_or_script =
+                    condition_result.return_from_function_or_script;
                 break;
             }
 
-            if condition_result.return_from_function_or_script {
+            if condition_result.is_success() != is_while {
                 break;
             }
 
             result = body.0.execute(shell, params).await?;
-            if result.return_from_function_or_script {
+            if result.exit_shell || result.return_from_function_or_script {
                 break;
             }
 
@@ -796,7 +804,7 @@ impl Execute for ast::ArithmeticForClauseCommand {
             }
 
             result = self.body.0.execute(shell, params).await?;
-            if result.return_from_function_or_script {
+            if result.exit_shell || result.return_from_function_or_script {
                 break;
             }
 

brush-shell/tests/cases/builtins/exit.yaml

@@ -7,3 +7,71 @@ cases:
   - name: "Exit with code"
     stdin: |
       exit 10
+
+  - name: "Exit in for loop"
+    stdin: |
+      for i in 1 2 3; do
+        exit 42
+        echo "Got past exit in loop"
+      done
+      echo "Got past loop"
+
+  - name: "Exit in arithmetic for loop body"
+    stdin: |
+      for ((i = 0; i < 10; i++)); do
+        exit 42
+        echo "Got past exit in loop"
+      done
+      echo "Got past loop"
+
+  - name: "Exit in while loop condition"
+    stdin: |
+      while exit 42; do
+        echo "In loop"
+      done
+      echo "Got past loop"
+
+  - name: "Exit in while loop body"
+    stdin: |
+      while true; do
+        exit 42
+        echo "Got past exit in body"
+        break
+      done
+      echo "Got past loop"
+
+  - name: "Exit in sequence"
+    stdin: |
+      exit 42; echo "Should not be printed"
+
+  - name: "Exit in function"
+    stdin: |
+      myfunc() {
+          exit 42
+          echo "Got past exit in function"
+      }
+
+      myfunc
+      echo "Got past function call"
+
+  - name: "Exit in subshell"
+    stdin: |
+      (exit 42)
+      echo "Got past subshell"
+
+  - name: "Exit in command substitution"
+    stdin: |
+      output=$(echo hi; exit 42; echo there)
+      echo "Got past command substitution"
+
+  - name: "Exit in and/or"
+    stdin: |
+      exit 42 || echo "Got past exit"
+
+  - name: "Exit in brace group"
+    stdin: |
+      { 
+        exit 42
+        echo "Got past exit"
+      }
+      echo "Got past brace group"

brush-shell/tests/cases/builtins/jobs.yaml

@@ -2,6 +2,7 @@ name: "Builtins: job-related builtins"
 cases:
   - name: "Basic async job"
     stdin: |
+      set +m
       echo hi &
       wait
       jobs

brush-shell/tests/cases/compound_cmds/subshell.yaml

@@ -23,3 +23,10 @@ cases:
   - name: "Piped subshell usage"
     stdin: |
       (echo hi) | wc -l
+
+  - name: "Breaks in subshell"
+    stdin: |
+      for i in 1 2 3; do
+        echo $i
+        (for i in 1 2 3; do break 2; done)
+      done