From 5b45399f5a57278dd2c8c15f27186d18147ad0b6 Mon Sep 17 00:00:00 2001
From: Stephen Sherratt <stephen@sherra.tt>
Date: Fri, 8 Aug 2025 15:57:18 +1000
Subject: [PATCH] Add posix sh env script

This amounted taking the bash env script and removing its use of the
`local` keyword and changing is extension to ".sh". The posix env script
also doesn't source the bash completion script as it uses some
bash-specific features.

This allows the dune binary distro to be used on machines with minimal
shells such as the ash shell in the default environment on alpine linux.

Also adds a test that runs shellcheck on env.sh to make sure it stays
posix-compatible.

Signed-off-by: Stephen Sherratt <stephen@sherra.tt>
---
 .github/workflows/test.yml    | 17 +++++++++++++++++
 extra/share/dune/env/env.bash |  3 +++
 extra/share/dune/env/env.sh   | 22 ++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 .github/workflows/test.yml
 create mode 100644 extra/share/dune/env/env.sh

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..0e9cfb2
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,17 @@
+name: test
+on: [push, pull_request]
+jobs:
+
+  shellcheck:
+    name: "Run shellcheck on the shell env script"
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: "Install shellcheck"
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y shellcheck
+    - name: "Run shellcheck on the shell env script"
+      run: |
+        # exclude warning for sourcing missing external file
+        shellcheck extra/share/dune/env/env.sh extra/share/dune/env/env.bash
diff --git a/extra/share/dune/env/env.bash b/extra/share/dune/env/env.bash
index 6f27d2a..de9292f 100644
--- a/extra/share/dune/env/env.bash
+++ b/extra/share/dune/env/env.bash
@@ -20,5 +20,8 @@ __dune_env() {
       ;;
   esac
 
+  # Load bash completions for dune.
+  # Suppress warning from shellcheck as it can't see the completion script.
+  # shellcheck disable=SC1091
   . "$ROOT"/share/bash-completion/completions/dune
 }
diff --git a/extra/share/dune/env/env.sh b/extra/share/dune/env/env.sh
new file mode 100644
index 0000000..f6ad1dc
--- /dev/null
+++ b/extra/share/dune/env/env.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+__dune_env() {
+  if [ "$#" != "1" ]; then
+    echo "__dune_env expected 1 argument, got $#"
+    return
+  fi
+  __dune_root="$1"
+
+  # Add dune to PATH unless it's already present.
+  # Affix colons on either side of $PATH to simplify matching (based on
+  # rustup's env script).
+  case :"$PATH": in
+    *:"$__dune_root/bin":*)
+      # Do nothing since the bin directory is already in PATH.
+      ;;
+    *)
+      # Prepending path in case a system-installed dune needs to be overridden
+      export PATH="$__dune_root/bin:$PATH"
+      ;;
+  esac
+}