Add v2 alpha

src/create_or_update_branch.py

@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+""" Create or Update Branch """
+import common as cmn
+from git import Repo, GitCommandError
+import os
+
+
+CHERRYPICK_EMPTY = (
+    "The previous cherry-pick is now empty, possibly due to conflict resolution."
+)
+
+
+def fetch_successful(repo, repo_url, branch):
+    try:
+        repo.git.fetch(repo_url, f"{branch}:refs/remotes/origin/{branch}")
+    except GitCommandError:
+        return False
+    return True
+
+
+def is_ahead(repo, branch_1, branch_2):
+    # Return true if branch_2 is ahead of branch_1
+    return (
+        int(repo.git.rev_list("--right-only", "--count", f"{branch_1}...{branch_2}"))
+        > 0
+    )
+
+
+def is_behind(repo, branch_1, branch_2):
+    # Return true if branch_2 is behind branch_1
+    return (
+        int(repo.git.rev_list("--left-only", "--count", f"{branch_1}...{branch_2}")) > 0
+    )
+
+
+def is_even(repo, branch_1, branch_2):
+    # Return true if branch_2 is even with branch_1
+    return not is_ahead(repo, branch_1, branch_2) and not is_behind(
+        repo, branch_1, branch_2
+    )
+
+
+def has_diff(repo, branch_1, branch_2):
+    diff = repo.git.diff(f"{branch_1}..{branch_2}")
+    return len(diff) > 0
+
+
+def create_or_update_branch(repo, repo_url, commit_message, base, branch):
+    # Set the default return values
+    action = "none"
+    diff = False
+
+    # Get the working base. This may or may not be the actual base.
+    working_base = repo.git.symbolic_ref("HEAD", "--short")
+    # If the base is not specified it is assumed to be the working base
+    if base is None:
+        base = working_base
+
+    # Save the working base changes to a temporary branch
+    temp_branch = cmn.get_random_string(length=20)
+    repo.git.checkout("HEAD", b=temp_branch)
+    # Commit any uncomitted changes
+    if repo.is_dirty(untracked_files=True):
+        print(f"Uncommitted changes found. Adding a commit.")
+        repo.git.add("-A")
+        repo.git.commit(m=commit_message)
+
+    # Perform fetch and reset the working base
+    # Commits made during the workflow will be removed
+    repo.git.fetch("--force", repo_url, f"{working_base}:{working_base}")
+
+    # If the working base is not the base, rebase the temp branch commits
+    if working_base != base:
+        print(
+            f"Rebasing commits made to branch '{working_base}' on to base branch '{base}'"
+        )
+        # Checkout the actual base
+        repo.git.fetch("--force", repo_url, f"{base}:{base}")
+        repo.git.checkout(base)
+        # Cherrypick commits from the temporary branch starting from the working base
+        commits = repo.git.rev_list("--reverse", f"{working_base}..{temp_branch}", ".")
+        for commit in commits.splitlines():
+            try:
+                repo.git.cherry_pick(
+                    "--strategy",
+                    "recursive",
+                    "--strategy-option",
+                    "theirs",
+                    f"{commit}",
+                )
+            except GitCommandError as e:
+                if CHERRYPICK_EMPTY not in e.stderr:
+                    print("Unexpected error: ", e)
+                    raise
+        # Reset the temp branch to the working index
+        repo.git.checkout("-B", temp_branch, "HEAD")
+        # Reset the base
+        repo.git.fetch("--force", repo_url, f"{base}:{base}")
+
+    # Try to fetch the pull request branch
+    if not fetch_successful(repo, repo_url, branch):
+        # The pull request branch does not exist
+        print(f"Pull request branch '{branch}' does not exist yet")
+        # Create the pull request branch
+        repo.git.checkout("HEAD", b=branch)
+        # Check if the pull request branch is ahead of the base
+        diff = is_ahead(repo, base, branch)
+        if diff:
+            action = "created"
+            print(f"Created branch '{branch}'")
+        else:
+            print(
+                f"Branch '{branch}' is not ahead of base '{base}' and will not be created"
+            )
+    else:
+        # The pull request branch exists
+        print(
+            f"Pull request branch '{branch}' already exists as remote branch 'origin/{branch}'"
+        )
+        # Checkout the pull request branch
+        repo.git.checkout(branch)
+
+        if has_diff(repo, branch, temp_branch):
+            # If the branch differs from the recreated temp version then the branch is reset
+            # For changes on base this action is similar to a rebase of the pull request branch
+            print(f"Resetting '{branch}'")
+            repo.git.checkout("-B", branch, temp_branch)
+            # repo.git.switch("-C", branch, temp_branch)
+
+        # Check if the pull request branch has been updated
+        # If the branch was reset or updated it will be ahead
+        # It may be behind if a reset now results in no diff with the base
+        if not is_even(repo, f"origin/{branch}", branch):
+            action = "updated"
+            print(f"Updated branch '{branch}'")
+        else:
+            print(
+                f"Branch '{branch}' is even with its remote and will not be updated"
+            )
+
+        # Check if the pull request branch is ahead of the base
+        diff = is_ahead(repo, base, branch)
+
+    # Delete the temporary branch
+    repo.git.branch("--delete", "--force", temp_branch)
+
+    return {"action": action, "diff": diff, "base": base}