Fix install-hooks.bash script

development.markdown

@@ -20,6 +20,14 @@ To get cracking with Unison:
 
 On startup, Unison prints a url for the codebase UI. If you did step 3 above, then visiting that URL in a browser will give you a nice interface to your codebase.
 
+## Git hooks
+
+There are some Git hooks provided by Unison. If you want to use them, you can run
+
+``` bash
+./scripts/install-hooks.bash
+```
+
 ## Autoformatting your code with Ormolu
 
 We use Ormolu (see [the specific version](./nix/versions.nix)) and CI will add an extra commit, if needed, to autoformat your code.

scripts/install-hooks.bash

@@ -1,9 +1,39 @@
 #!/usr/bin/env bash
+set -euo pipefail
+SCRIPTNAME="$(readlink -f -- "${BASH_SOURCE[0]}")"
+SCRIPTDIR="$(dirname -- "$SCRIPTNAME")"
 
-GIT_DIR=$(git rev-parse --git-dir)
+function usage {
+    echo "Usage: $SCRIPTNAME [-f] [-h]"
+    echo
+    echo "  -f   Overwrite hooks if they already exist"
+    echo "  -h   Show this usage message"
+}
+
+trap "echo; usage" ERR
+
+force=("-n")
+while getopts ':fh' OPTION; do
+    case "$OPTION" in
+        f)
+            force=("-f")
+            ;;
+        h)
+            usage
+            exit 0
+            ;;
+        \?)
+            usage
+            exit 1
+            ;;
+    esac
+done
+
+hooks_dir=$(git rev-parse --git-path hooks)
 
 echo "Installing hooks..."
+mkdir -p "$hooks_dir"
 # this command creates symlink to our pre-commit script
-ln -s ../../scripts/pre-commit.bash $GIT_DIR/hooks/pre-commit
-ln -s ../../scripts/pre-push.bash $GIT_DIR/hooks/pre-push
+cp "${force[@]}" "$SCRIPTDIR/pre-commit.bash" "$hooks_dir/pre-commit"
+cp "${force[@]}" "$SCRIPTDIR/pre-push.bash" "$hooks_dir/pre-push"
 echo "Done!"

scripts/pre-commit.bash

@@ -1,10 +1,9 @@
 #!/usr/bin/env bash
+set -euo pipefail
 
-echo "Running pre-commit hook from "`pwd`
-./scripts/test.sh
+echo "Running pre-commit hook from $(pwd)"
 
-# $? stores exit value of the last command
-if [ $? -ne 0 ]; then
- echo "Tests must pass before commit!"
- exit 1
+if ! ./scripts/test.sh; then
+    echo "Tests must pass before commit!"
+    exit 1
 fi

scripts/pre-push.bash

@@ -1,18 +1,16 @@
 #!/bin/bash
-# Run the following command in the root of your project to install this pre-push hook:
-# cp git-hooks/pre-push .git/hooks/pre-push; chmod 700 .git/hooks/pre-push
+set -euo pipefail
+
+# Run `./install-hooks.bash` to install this pre-push hook.
 
 # Check if we actually have commits to push
-commits=`git log @{u}..`
+commits=$(git log "@{u}..")
 if [ -z "$commits" ]; then
     exit 0
 fi
 
 CMD="./scripts/test.sh"
-eval $CMD
-RESULT=$?
-if [ $RESULT -ne 0 ]; then
-    echo "The git push operation was canceled because \`$CMD\` did not complete successfully."
+if ! "$CMD"; then
+    echo "The git push operation was canceled because ‘$CMD’ did not complete successfully."
     exit 1
 fi
-exit 0