From b7638754c0856b1bb5f911985190419ecb5e267b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sat, 22 Aug 2026 21:55:01 +0200
Subject: Shell: allow to toggle "exit on error"

Changelog: Implemented "set +e/-e" in the shell interpreter.
---
 README.md                      |  3 +++
 src/Script/Shell.hs            | 16 ++++++++++++++--
 test/asset/shell/error-exit.et | 18 ++++++++++++++++++
 test/script/shell.et           | 26 ++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 2 deletions(-)
 create mode 100644 test/asset/shell/error-exit.et

diff --git a/README.md b/README.md
index c184bda..6d5baf1 100644
--- a/README.md
+++ b/README.md
@@ -416,6 +416,9 @@ Where `<node>` is the network node on which to run the script (it will be run in
 and `<name>`, if given, is the name of the variable that will refer to the shell process (this can be used e.g. in the `expect` command to check the standard output of the script).
 As with the `spawn` command, the resulting process is terminated at the end of the current scope.
 
+By default the shell process exists with failure whenever any command exits with non-zero status.
+This behavior can be disabled using the `set +e` command (and re-enabled with `set -e`).
+
 
 ### Functions
 
diff --git a/src/Script/Shell.hs b/src/Script/Shell.hs
index 983e40f..29e2324 100644
--- a/src/Script/Shell.hs
+++ b/src/Script/Shell.hs
@@ -46,6 +46,7 @@ newtype ShellScript = ShellScript [ ShellStatement ]
 data ShellState = ShellState
     { shellWorkingDirectory :: FilePath
     , shellOldWorkingDirectory :: FilePath
+    , shellExitOnError :: Bool
     }
 
 data ShellStatement = ShellStatement
@@ -135,8 +136,9 @@ executeCommand sei@ShellExecInfo {..} st pstdin pstdout pstderr scmd@ShellComman
 
     ( getExitStatus, state' ) <- executeCommandProcess sei st (handledHandle pstdin') (handledHandle pstdout') (handledHandle pstderr') args cmdCommand
     let failedWithStatus status = do
-            liftIO $ putMVar seiStatusVar status
-            () <- throwError Failed
+            when (shellExitOnError st) $ do
+                liftIO $ putMVar seiStatusVar status
+                throwError Failed
             return state'
 
     mapM_ closeIfRequested [ pstdin', pstdout', pstderr' ]
@@ -191,6 +193,15 @@ executeCommandProcess ShellExecInfo {..} st@ShellState {..} pstdin pstdout pstde
             liftIO $ hPutStrLn pstderr $ "pwd: too many arguments"
             return ( return (Exited (ExitFailure (-1))), st )
 
+    "set"
+        | [ "+e" ] <- args -> do
+            return ( return (Exited ExitSuccess), st { shellExitOnError = False } )
+        | [ "-e" ] <- args -> do
+            return ( return (Exited ExitSuccess), st { shellExitOnError = True } )
+        | otherwise -> do
+            liftIO $ hPutStrLn pstderr $ "set: " <> T.unpack (T.unwords args) <> ": not implemented"
+            return ( return (Exited (ExitFailure (-1))), st )
+
     cmd -> liftIO $ do
         (_, _, _, phandle) <- createProcess_ "shell"
             (proc (T.unpack cmd) (map T.unpack args))
@@ -231,6 +242,7 @@ executeScript sei@ShellExecInfo {..} pstdin pstdout pstderr (ShellScript stateme
     let initialState = ShellState
             { shellWorkingDirectory = nodeDir seiNode
             , shellOldWorkingDirectory = nodeDir seiNode
+            , shellExitOnError = True
             }
     _ <- (\f -> foldM f initialState statements) $ \st ShellStatement {..} -> do
         executePipeline sei st (KeepHandle pstdin) (KeepHandle pstdout) (KeepHandle pstderr) shellPipeline
diff --git a/test/asset/shell/error-exit.et b/test/asset/shell/error-exit.et
new file mode 100644
index 0000000..feddf64
--- /dev/null
+++ b/test/asset/shell/error-exit.et
@@ -0,0 +1,18 @@
+test Default:
+    node n
+    shell on n as sh:
+        false
+
+test Disabled:
+    node n
+    shell on n as sh:
+        set +e
+        false
+
+test Enabled:
+    node n
+    shell on n as sh:
+        set +e
+        false
+        set -e
+        false
diff --git a/test/script/shell.et b/test/script/shell.et
index fbf385d..e63093b 100644
--- a/test/script/shell.et
+++ b/test/script/shell.et
@@ -123,3 +123,29 @@ test ShellWorkingDirectory:
             "$home"
             "$home"
             "/tmp"
+
+
+test ShellExitOnError:
+    spawn as p
+    with p:
+        send "load ${scripts.path}/error-exit.et"
+        local:
+            expect /(load-.*)/ capture done
+            guard (done == "load-done")
+
+        send "run Default"
+        expect /child-fail sh failed at: .*error-exit.et:4:9: false/
+        expect /run-test-result Default failed/
+        expect /run-done/
+        flush
+
+        send "run Disabled"
+        expect /run-test-result Disabled done/
+        expect /run-done/
+        flush
+
+        send "run Enabled"
+        expect /child-fail sh failed at: .*error-exit.et:18:9: false/
+        expect /run-test-result Enabled failed/
+        expect /run-done/
+        flush
-- 
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