Make it possible to merge changes up through release branches

Author: xolox

vcs_repo_mgr/__init__.py

@@ -87,7 +87,7 @@
 
 # External dependencies.
 from executor import execute, quote
-from humanfriendly import coerce_boolean, compact, concatenate, format, format_path, parse_path
+from humanfriendly import Timer, coerce_boolean, compact, concatenate, format, format_path, parse_path, pluralize
 from natsort import natsort, natsort_key
 from property_manager import PropertyManager, lazy_property, required_property, writable_property
 from six import string_types
@@ -104,7 +104,7 @@
 )
 
 # Semi-standard module versioning.
-__version__ = '0.28'
+__version__ = '0.29'
 
 USER_CONFIG_FILE = os.path.expanduser('~/.vcs-repo-mgr.ini')
 """The absolute pathname of the user-specific configuration file (a string)."""
@@ -872,6 +872,100 @@ def merge(self, revision=None):
             **self.get_author()
         ))
 
+    def merge_up(self, target_branch=None, feature_branch=None, delete=True):
+        """
+        Merge a change into one or more release branches and the default branch.
+
+        :param target_branch: The name of the release branch where merging of
+                              the feature branch starts (a string or
+                              :data:`None`, defaults to
+                              :attr:`current_branch`).
+        :param feature_branch: The feature branch to merge in (a string or
+                               :data:`None`). Strings are parsed using
+                               :class:`FeatureBranchSpec`.
+        :param delete: :data:`True` (the default) to delete or close the
+                       feature branch after it is merged, :data:`False`
+                       otherwise.
+        :returns: If `feature_branch` is given the global revision id of the
+                  feature branch is returned, otherwise the global revision id
+                  of the target branch (before any merges performed by
+                  :func:`merge_up()`) is returned.
+        :raises: The following exceptions can be raised:
+
+                 - :exc:`~exceptions.TypeError` when `target_branch` and
+                   :attr:`current_branch` are both :data:`None`.
+                 - :exc:`~exceptions.ValueError` when the given target branch
+                   doesn't exist (based on :attr:`branches`).
+        """
+        timer = Timer()
+        # Validate the target branch or select the default target branch.
+        if target_branch:
+            if target_branch not in self.branches:
+                raise ValueError("The target branch %r doesn't exist!" % target_branch)
+        else:
+            target_branch = self.current_branch
+            if not target_branch:
+                raise TypeError("You need to specify the target branch! (where merging starts)")
+        # Parse the feature branch specification.
+        feature_branch = FeatureBranchSpec(feature_branch) if feature_branch else None
+        # Make sure we start with a clean working tree.
+        self.ensure_clean()
+        # Make sure we're up to date with our upstream repository (if any).
+        self.update()
+        # Check out the target branch.
+        self.checkout(revision=target_branch)
+        # Get the global revision id of the release branch we're about to merge.
+        revision_to_merge = self.find_revision_id(target_branch)
+        # Check if we need to merge in a feature branch.
+        if feature_branch:
+            if feature_branch.location:
+                # Pull in the feature branch.
+                self.update(remote=feature_branch.location)
+            # Get the global revision id of the feature branch we're about to merge.
+            revision_to_merge = self.find_revision_id(feature_branch.revision)
+            # Merge in the feature branch.
+            self.merge(revision=feature_branch.revision)
+            # Commit the merge.
+            self.commit(message="Merged %s" % feature_branch.expression)
+        # Find the release branches in the repository.
+        release_branches = [release.revision.branch for release in self.ordered_releases]
+        logger.debug("Found %s: %s",
+                     pluralize(len(release_branches), "release branch", "release branches"),
+                     concatenate(release_branches))
+        # Find the release branches after the target branch.
+        later_branches = release_branches[release_branches.index(target_branch) + 1:]
+        logger.info("Found %s after target branch (%s): %s",
+                    pluralize(len(later_branches), "release branch", "release branches"),
+                    target_branch,
+                    concatenate(later_branches))
+        # Determine the branches that need to be merged.
+        branches_to_upmerge = later_branches + [self.default_revision]
+        logger.info("Merging up from %s to %s: %s",
+                    target_branch,
+                    pluralize(len(branches_to_upmerge), "branch", "branches"),
+                    concatenate(branches_to_upmerge))
+        # Merge the feature branch up through the selected branches.
+        merge_queue = [target_branch] + branches_to_upmerge
+        while len(merge_queue) >= 2:
+            from_branch = merge_queue[0]
+            to_branch = merge_queue[1]
+            logger.info("Merging %s into %s ..", from_branch, to_branch)
+            self.checkout(revision=to_branch)
+            self.merge(revision=from_branch)
+            self.commit(message="Merged %s" % from_branch)
+            merge_queue.pop(0)
+        # Check if we need to delete or close the feature branch.
+        if delete and feature_branch and feature_branch.revision in self.branches:
+            # Delete or close the feature branch.
+            self.delete_branch(
+                branch_name=feature_branch.revision,
+                message="Closing feature branch %s" % feature_branch.revision,
+            )
+            # Update the working tree to the default branch.
+            self.checkout()
+        logger.info("Done! Finished merging up in %s.", timer)
+        return revision_to_merge
+
     def add_files(self, *pathnames, **kw):
         """
         Stage new files in the working tree to be included in the next commit.
@@ -1412,6 +1506,68 @@ def __repr__(self):
         ]))
 
 
+class FeatureBranchSpec(PropertyManager):
+
+    """Simple and human friendly feature branch specifications."""
+
+    def __init__(self, expression):
+        """
+        Initialize a :class:`FeatureBranchSpec` object.
+
+        :param expression: A feature branch specification (a string).
+
+        The `expression` string is parsed as follows:
+
+        - If `expression` contains two nonempty substrings separated by the
+          character ``#`` it is split into two parts where the first part is
+          used to set :attr:`location` and the second part is used to set
+          :attr:`revision`.
+        - Otherwise `expression` is interpreted as a revision without a
+          location (in this case :attr:`location` will be :data:`None`).
+
+        Some examples to make things more concrete:
+
+        >>> from vcs_repo_mgr import FeatureBranchSpec
+        >>> FeatureBranchSpec('https://github.com/xolox/python-vcs-repo-mgr.git#remote-feature-branch')
+        FeatureBranchSpec(expression='https://github.com/xolox/python-vcs-repo-mgr.git#remote-feature-branch',
+                          location='https://github.com/xolox/python-vcs-repo-mgr.git',
+                          revision='remote-feature-branch')
+        >>> FeatureBranchSpec('local-feature-branch')
+        FeatureBranchSpec(expression='local-feature-branch',
+                          location=None,
+                          revision='local-feature-branch')
+        """
+        super(FeatureBranchSpec, self).__init__(expression=expression)
+
+    @required_property
+    def expression(self):
+        """The feature branch specification provided by the user (a string)."""
+
+    @writable_property
+    def location(self):
+        """
+        The location of the repository that contains :attr:`revision` (a string or :data:`None`).
+
+        The computed default value of :attr:`location` is based on the value of
+        :attr:`expression` as described in the documentation of
+        :func:`__init__()`.
+        """
+        location, _, revision = self.expression.partition('#')
+        return location if location and revision else None
+
+    @required_property
+    def revision(self):
+        """
+        The name of the feature branch (a string).
+
+        The computed default value of :attr:`revision` is based on the value of
+        :attr:`expression` as described in the documentation of
+        :func:`__init__()`.
+        """
+        location, _, revision = self.expression.partition('#')
+        return revision if location and revision else self.expression
+
+
 class HgRepo(Repository):
 
     """

vcs_repo_mgr/tests.py

@@ -314,14 +314,7 @@ def check_working_tree_support(self, source_repo, file_to_change='setup.py'):
         # Make sure the source repository contains a bare checkout.
         assert source_repo.is_bare, "Expected a bare repository checkout!"
         # Create a clone of the repository that does have a working tree.
-        # TODO Cloning of repository objects might deserve being a feature?
-        kw = dict((n, getattr(source_repo, n)) for n in ('release_scheme', 'release_filter', 'default_revision'))
-        cloned_repo = source_repo.__class__(
-            author="Peter Odding <vcs-repo-mgr@peterodding.com>",
-            local=create_temporary_directory(),
-            remote=source_repo.local,
-            bare=False, **kw
-        )
+        cloned_repo = self.clone_repo(source_repo, bare=False)
         # Make sure the clone doesn't exist yet.
         assert not cloned_repo.exists
         # Create the clone.
@@ -345,6 +338,20 @@ def check_working_tree_support(self, source_repo, file_to_change='setup.py'):
         self.check_checkout_support(cloned_repo)
         self.check_commit_support(cloned_repo)
         self.check_branch_support(cloned_repo)
+        self.check_merge_up_support(cloned_repo)
+
+    def clone_repo(self, repository, **kw):
+        """Clone a repository object."""
+        # TODO Cloning of repository objects might deserve being a feature?
+        properties = 'bare', 'default_revision', 'release_scheme', 'release_filter'
+        options = dict((n, getattr(repository, n)) for n in properties)
+        options.update(kw)
+        return repository.__class__(
+            author="Peter Odding <vcs-repo-mgr@peterodding.com>",
+            local=create_temporary_directory(),
+            remote=repository.local,
+            **options
+        )
 
     def check_checkout_support(self, repository):
         """Make sure that checkout() works and it can clean the working tree."""
@@ -439,6 +446,54 @@ def check_merge_support(self, repository, source_branch, target_branch):
         except NotImplementedError as e:
             logger.warning("%s", e)
 
+    def check_merge_up_support(self, repository, num_branches=5):
+        """Make sure we can merge changes up through release branches."""
+        logger.info("Testing merge_up() support ..")
+        try:
+            # Clone the repository with a custom release scheme/filter.
+            repository = self.clone_repo(
+                repository, bare=False,
+                release_scheme='branches',
+                release_filter='^v(\d*)$',
+            )
+            # Pick a directory name of which we can reasonably expect that
+            # no existing repository will already contain this directory.
+            unique_directory = 'vcs-repo-mgr-merge-up-support-%s' % random_string()
+            absolute_directory = os.path.join(repository.local, unique_directory)
+            # Create the release branches.
+            previous_branch = repository.current_branch
+            for i in range(1, num_branches + 1):
+                branch_name = 'v%i' % i
+                repository.checkout(revision=previous_branch)
+                repository.create_branch(branch_name)
+                if not os.path.isdir(absolute_directory):
+                    os.mkdir(absolute_directory)
+                with open(os.path.join(absolute_directory, branch_name), 'w') as handle:
+                    handle.write("Version %i\n" % i)
+                repository.add_files(all=True)
+                repository.commit(message="Create release branch %s" % branch_name)
+                previous_branch = branch_name
+            # Create a feature branch based on the initial release branch.
+            feature_branch = 'vcs-repo-mgr-feature-branch-%s' % random_string()
+            repository.checkout('v1')
+            repository.create_branch(feature_branch)
+            with open(os.path.join(absolute_directory, 'v1'), 'w') as handle:
+                handle.write("Version 1.1\n")
+            repository.commit(message="Fixed a bug in version 1")
+            assert feature_branch in repository.branches
+            # Merge the change up into the release branches.
+            expected_revision = repository.find_revision_id(revision=feature_branch)
+            merged_revision = repository.merge_up(target_branch='v1', feature_branch=feature_branch)
+            assert merged_revision == expected_revision
+            # Make sure the feature branch was closed.
+            assert feature_branch not in repository.branches
+            # Validate the contents of the default branch.
+            repository.checkout()
+            entries = os.listdir(absolute_directory)
+            assert all('v%i' % i in entries for i in range(1, num_branches + 1))
+        except NotImplementedError as e:
+            logger.warning("%s", e)
+
     def mutate_working_tree(self, repository):
         """Mutate an arbitrary tracked file in the repository's working tree."""
         vcs_directory = os.path.abspath(repository.vcs_directory)