Merge pull request whyrusleeping#201 from whyrusleeping/feat/contrib

contrib: add gx-retrotag script

contrib/README.md

@@ -0,0 +1,16 @@
+# Scripts that make using GX nicer
+
+## gx-retrotag
+
+`gx-retrotag` retroactively adds git tags to commits that modify .gx/lastpubver
+(gx release commits).
+
+1. Fetches $remote (defaults to origin).
+2. Tags the relevant commits (on $branch only, defaults to master).
+3. Pushes the tags back to $remote.
+
+Usage:
+
+```sh
+> ./gx-retrotag.sh [[remote] branch]
+```

contrib/gx-retrotag.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+remote=${1:-origin}
+branch=${2:-master}
+
+echo "fetching $remote"
+git fetch "$remote"
+
+for h in $(git log "$remote/$branch" --format=format:'%H' .gx/lastpubver); do
+    # get the gx version at this point
+    ver="$(git show $h:.gx/lastpubver 2>/dev/null | cut -d: -f1)" || continue
+
+    # Skip empty versions
+    [[ -n "$ver" ]] || continue
+
+
+    # skip if the tag exists
+    if git show-ref "v$ver" "$ver" >/dev/null; then
+        continue
+    fi
+
+    # tag it.
+    echo "tagging $ver ($h)"
+    git tag -s -m "release $ver" "v$ver" $h
+    changed=true
+done
+
+if [[ -n "$changed" ]]; then
+    echo "pushing tags to $remote"
+    git push --tags --repo="$remote"
+else
+    echo "nothing to do"
+fi