Add --merge option to select which branches get merged back into main

Signed-off-by: Jacob Stopak <[email protected]>

Author: initialcommit-io

README.md

@@ -7,21 +7,22 @@
 
 Generate dummy Git repositories and populate them with the desired number of commits, branches, and structure.
 
-Example: `$ git-dummy --commits=10 --branches=2 --diverge-at=3`
+Example: `$ git-dummy --commits=10 --branches=4 --merge=1`
 
-This will initialize a new Git repo in the current directory with 2 branches, each containing 10 commits.
+This will initialize a new Git repo in the current directory with 4 branches, each containing 10 commits, 1 of which is merged back into `main`.
 
-Note: All generated dummy repos have at minimum 1 branch called `main`. For dummies with multiple branches, branches are named `branch1, branch2, ..., branchN`. Each branch currently branches off of `main` at `--diverge-at` if supplied, or else a randomly chosen commit. The length of each branch is capped at the number of commits specified by `--commits`.
+Note: All generated dummy repos have at minimum 1 branch called `main`. For dummies with multiple branches, branches are named `branch1, branch2, ..., branchN`. Each branch currently branches off of `main` at `--diverge-at` if supplied, or else a randomly chosen commit. The length of each branch is capped at the number of commits specified by `--commits`. Use `--merge=x,y,...,n` to select which branches get merged back into `main`. 
 
 ## Use cases
 - Programatically generate Git repos for functional testing of Git tools
 - Decide how many commits and branches are generated
+- Select which branches get merged back into `main`
 - Mimic scenarios in real Git repos to practice on without touching real data
 - Generate Git demo repos to teach or learn from
 
 ## Features
 - Run a one-liner git-dummy command in the terminal to generate a dummy Git repo based on your parameters
-- Customize the repo name, path, number of commits, branches, and structure
+- Customize the repo name, path, number of commits, branches, merges, and structure
 
 ## Quickstart
 
@@ -61,7 +62,8 @@ Available options and flags include:
 `--name`: The name of the dummy Git repo, defaults to "dummy".  
 `--commits`: The number of commits to populate in the dummy Git repo, defaults to 5.  
 `--branches`: The number of branches to generate in the dummy Git repo, defaults to 1.  
-`--diverge-at`: The commit number at which branches diverge from `main`.
+`--diverge-at`: The commit number at which branches diverge from `main`.  
+`--merge`: A comma separated list of branch postfix ids to merge back into `main`.  
 `--git-dir`: The path at which to store the dummy Git repo, defaults to current directory.
 
 ## Command examples
@@ -77,6 +79,12 @@ Generate a dummy repo with 4 branches `main`, `branch1`, `branch2`, and `branch3
 $ git-dummy --branches=4 --diverge-at=2
 ```
 
+Generate a dummy repo with 4 branches, so that `branch1` and `branch3` are merged back into `main`:
+
+```console
+$ git-dummy --branches=4 --merge=1,3
+```
+
 For convenience, environment variables can be set for any command-line option available in git-dummy. All environment variables start with `git_dummy_` followed by the name of the option.
 
 For example, the `--git-dir` option can be set as an environment variable like:

git_dummy/__main__.py

@@ -31,12 +31,17 @@ def main(
         settings.diverge_at,
         help="The point branches diverge from main at",
     ),
+    merge: str = typer.Option(
+        settings.merge,
+        help="Comma separated branch ids to merge back into main",
+    ),
 ):
     settings.name = name
     settings.git_dir = os.path.join(os.path.expanduser(git_dir), name)
     settings.commits = commits
     settings.branches = branches
     settings.diverge_at = diverge_at
+    settings.merge = merge
 
     repo = git.Repo.init(settings.git_dir)
     repo.config_writer().set_value("init", "defaultBranch", "main").release()
@@ -61,6 +66,19 @@ def main(
             open(os.path.join(settings.git_dir, f"{branch_name}.{d}"), "a").close()
             repo.index.add([f"{branch_name}.{d}"])
             repo.index.commit(f"Dummy commit #{d} on {branch_name}")
+        if settings.merge:
+            to_merge = settings.merge.split(",")
+            if str(settings.branches - 1) in to_merge:
+                repo.git.checkout("main")
+                main = repo.branches["main"]
+                branch = repo.branches[branch_name]
+                base = repo.git.merge_base(main, branch)
+                repo.index.merge_tree(branch, base=base)
+                repo.index.commit(
+                    f"Merge {branch_name} into main",
+                    parent_commits=(branch.commit, main.commit),
+                )
+                main.checkout(force=True)
 
         settings.branches -= 1
 

git_dummy/settings.py

@@ -8,6 +8,7 @@ class Settings(BaseSettings):
     commits = 5
     branches = 1
     diverge_at = 0
+    merge = ""
 
     class Config:
         env_prefix = "git_dummy_"