Merge pull request #21 from EventAccess/pr-improve-update-1

Make update.sh more robust

Author: oddstr13

update.sh

@@ -1,13 +1,39 @@
 #!/bin/bash
 set -ex
 
-# Fetch updates
-git fetch origin dev
-git checkout dev
-git pull --ff-only
+# Update default branch
+function update_default_branch() {
+    default_branch=$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@@')
+    current_branch=$(git branch --show-current)
+
+    # if on default branch or detached HEAD
+    if [ "$current_branch" = "$default_branch" ] || [ -z "$current_branch" ]; then
+        # We are on dev branch, fast-forward it
+        git fetch origin "${default_branch}"
+        git checkout "${default_branch}"
+
+        # if pull failed and we are in detached HEAD with local changes, abort
+        if ! git pull --ff-only origin "${default_branch}" \
+        && [ -z "$current_branch" ] \
+        && [ -n "$(git status --porcelain --ignore-submodules=dirty)" ]; then
+            # Not sure exactly how this happened,
+            # possibly due to failed dev:dev fetch in an earlier iteration.
+            echo
+            pwd
+            echo
+            git status --porcelain --ignore-submodules=dirty
+            echo
+            echo "!!! ERROR !!! Detached HEAD with local changes & failed to fast-forward, aborting."
+            echo "Tell Odd."
+            echo
+            exit 1
+        fi
+    else
+        # Fast-forward dev branch without switching to it
+        git fetch origin "${default_branch}:${default_branch}"
+    fi
+}
 
-# Initialize git submodules
-git submodule update --init --recursive
 
 
 # Set up (ssh) push access for submodules
@@ -23,17 +49,26 @@ function ensure_ssh_push_submodules() {
             newurl=$(sed -E 's!https?://github.com/!git@github.com:!g' <<< "${url}")
             pushd "${dir}" > /dev/null
                 git remote set-url --push origin "${newurl}"
-                default_branch=$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@@')
-                git fetch origin "${default_branch}"
-                git checkout "${default_branch}"
-                git pull --ff-only
+
+                update_default_branch
+
                 ensure_ssh_push_submodules
             popd > /dev/null
         done <<< "${IN[@]}"
     fi
 }
 
+
+# Fetch updates
+update_default_branch
+
+# Initialize git submodules
+git submodule update --init --recursive
+
 ensure_ssh_push_submodules
 
 # TODO: Set up pre-commit
 # Issue URL: https://github.com/EventAccess/Meta/issues/18
+
+# TODO: Prune merged branches
+#   git branch --merged | grep -Ev "(^\*|^\+|^\s*(master|main|dev)\s*$)" | xargs --no-run-if-empty git branch -d