Reseting the file cache when changing the target branch

* Fixing cache files bug

* Bumped the version and updated changelog

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com),
 and this project adheres to [Semantic Versioning](https://semver.org).
 
+## [1.4.1] - 2020-06-18
+### Fixed
+- set_target_branch was not cleaning the file cache, resulting in gordian not being able to get new files in the new branches.
+
 ## [1.4.0] - 2020-06-17
 ### Added
 - Print out PR URLs at the end of a Gordian run

gordian/repo.py

@@ -40,6 +40,7 @@ def __init__(self, repo_name, github_api_url=None, branch=None, git=None, files=
         self.dirty = False
         self.new_version = None
         self.semver_label = semver_label
+        self.target_branch = None
         self.set_target_branch(target_branch)
 
         logger.debug(f'Target ref: {target_branch}')
@@ -50,8 +51,13 @@ def __init__(self, repo_name, github_api_url=None, branch=None, git=None, files=
         logger.debug(f'Branch name for this changes: {self.branch_name}')
 
     def set_target_branch(self, branch):
+        if branch == self.target_branch:
+            return
+
         self.target_branch = branch
         self.target_ref = f"refs/heads/{self.target_branch}"
+        # Resetting the file cache when we change the branch
+        self.files = []
 
     def get_objects(self, filename, klass=None):
         file = self.find_file(filename)

setup.py

@@ -3,7 +3,7 @@
 setup_reqs = ['pytest', 'pytest-cov', 'pytest-runner', 'flake8']
 setuptools.setup(
     name="gordian",
-    version="1.4.0",
+    version="1.4.1",
     author="Intuit",
     author_email="[email protected]",
     description="A tool to search and replace files in a Git repo",

tests/test_repo.py

@@ -58,3 +58,14 @@ def test_get_files(self):
         self.repo.get_files()
         self.repo._repo.get_contents.assert_has_calls([call('', 'refs/heads/target'), call('directory', 'refs/heads/target')])
         self.assertEquals(self.repo.files, [repository_file])
+
+    def test_set_target_branch(self):
+        cached_files = ['cached_file', 'cached_file', 'cached_file']
+        self.repo.files = cached_files.copy()
+        self.repo.set_target_branch('master')
+        self.assertEqual(self.repo.files, cached_files)
+
+        self.repo.set_target_branch('Something different')
+        self.assertEqual(self.repo.files, [])
+        self.assertEqual(self.repo.target_branch, 'Something different')
+        self.assertEqual(self.repo.target_ref, 'refs/heads/Something different')