scripts : add pr2wt.sh (#18644)

* scripts : add pr2wt.sh

* script : shebang

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

.gitignore

@@ -130,6 +130,7 @@ poetry.toml
 # Local scripts
 /run-vim.sh
 /run-chat.sh
+/run-spec.sh
 /.ccache/
 
 # IDE

scripts/pr2wt.sh

@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+
+# intialize a new worktree from a PR number:
+#
+# - creates a new remote using the fork's clone URL
+# - creates a local branch tracking the remote branch
+# - creates a new worktree in a parent folder, suffixed with "-pr-${PR}"
+#
+# sample usage:
+#   ./scripts/pr2wt.sh 12345
+#   ./scripts/pr2wt.sh 12345 opencode
+
+function usage() {
+    echo "usage: $0 <pr_number> [cmd]"
+    exit 1
+}
+
+# check we are in the right directory
+if [[ ! -f "scripts/pr2wt.sh" ]]; then
+    echo "error: this script must be run from the root of the repository"
+    exit 1
+fi
+
+if [[ $# -lt 1 || $# -gt 2 ]]; then
+    usage
+fi
+
+PR=$1
+[[ "$PR" =~ ^[0-9]+$ ]] || { echo "error: PR number must be numeric"; exit 1; }
+
+url_origin=$(git config --get remote.origin.url) || {
+    echo "error: no remote named 'origin' in this repository"
+    exit 1
+}
+
+org_repo=$(echo $url_origin | cut -d/ -f4-)
+
+echo "org/repo: $org_repo"
+
+meta=$(curl -sSf -H "Accept: application/vnd.github+json" "https://api.github.com/repos/${org_repo}/pulls/${PR}")
+
+url_remote=$(echo "$meta" | jq -r '.head.repo.clone_url')
+head_ref=$(echo "$meta" | jq -r '.head.ref')
+
+echo "url:      $url_remote"
+echo "head_ref: $head_ref"
+
+git remote rm  pr/${PR}
+git remote add pr/${PR} $url_remote
+git fetch      pr/${PR} $head_ref
+
+dir=$(basename $(pwd))
+
+git branch -D pr/$PR 2> /dev/null
+git worktree add -b pr/$PR ../$dir-pr-$PR pr/$PR/${head_ref} 2> /dev/null
+
+wt_path=$(cd ../$dir-pr-$PR && pwd)
+
+echo "git worktree created in $wt_path"
+
+# if a command was provided, execute it
+if [[ $# -eq 2 ]]; then
+    cd ../$dir-pr-$PR
+    exec $2
+fi