fix(history): Fix changelog generation

This enables regeneration of a given versions changelog.

semantic_release/history/__init__.py

@@ -4,6 +4,7 @@
 from invoke import run
 
 from ..settings import config
+from ..vcs_helpers import get_commit_log
 from .logs import evaluate_version_bump  # noqa
 
 from .parser_angular import parse_commit_message as angular_parser  # noqa isort:skip
@@ -31,6 +32,21 @@ def get_new_version(current_version, level_bump):
         return current_version
     return getattr(semver, 'bump_{0}'.format(level_bump))(current_version)
 
+def get_previous_version(version):
+    """
+    Returns the version prior to the given version.
+
+    :param version: A string with the version number.
+    """
+    found_version = False
+    for commit_message in get_commit_log():
+        if version in commit_message:
+            found_version = True
+        if found_version:
+            if re.match(r'\d+.\d+.\d+', commit_message):
+                return commit_message.replace('v', '')
+
+
 
 def set_new_version(new_version):
     """

semantic_release/history/logs.py

@@ -53,7 +53,7 @@ def evaluate_version_bump(current_version, force=None):
     return bump
 
 
-def generate_changelog(version):
+def generate_changelog(from_version, to_version=None):
     """
     Generates a changelog for the given version.
 
@@ -63,8 +63,16 @@ def generate_changelog(version):
 
     changes = {'feature': [], 'fix': [], 'documentation': [], 'refactor': [], 'breaking': []}
 
+    found_the_release = to_version is None
+
     for commit_message in get_commit_log():
-        if version in commit_message:
+        if not found_the_release:
+            if to_version and to_version not in commit_message:
+                continue
+            else:
+                found_the_release = True
+
+        if from_version is not None and from_version in commit_message:
             break
 
         try: