fixes #689

Author: jph00

nbdev/cli.py

@@ -144,20 +144,21 @@ def update_version():
     with open(fname, 'w') as f: f.write(code)
 
 
-def bump_version(version, part=2):
+def bump_version(version, part=2, unbump=False):
     version = version.split('.')
-    version[part] = str(int(version[part]) + 1)
+    incr = -1 if unbump else 1
+    version[part] = str(int(version[part]) + incr)
     for i in range(part+1, 3): version[i] = '0'
     return '.'.join(version)
 
 @call_parse
 def nbdev_bump_version(
-    part:int=2  # Part of version to bump
-):
+    part:int=2,  # Part of version to bump
+    unbump:bool=False):  # Reduce version instead of increasing it
     "Increment version in settings.ini by one"
     cfg = get_config()
     print(f'Old version: {cfg.version}')
-    cfg.d['version'] = bump_version(get_config().version, part)
+    cfg.d['version'] = bump_version(get_config().version, part, unbump=unbump)
     cfg.save()
     update_version()
     print(f'New version: {cfg.version}')

nbs/10_cli.ipynb

@@ -261,20 +261,21 @@
     "    with open(fname, 'w') as f: f.write(code)\n",
     "\n",
     "\n",
-    "def bump_version(version, part=2):\n",
+    "def bump_version(version, part=2, unbump=False):\n",
     "    version = version.split('.')\n",
-    "    version[part] = str(int(version[part]) + 1)\n",
+    "    incr = -1 if unbump else 1\n",
+    "    version[part] = str(int(version[part]) + incr)\n",
     "    for i in range(part+1, 3): version[i] = '0'\n",
     "    return '.'.join(version)\n",
     "\n",
     "@call_parse\n",
     "def nbdev_bump_version(\n",
-    "    part:int=2  # Part of version to bump\n",
-    "):\n",
+    "    part:int=2,  # Part of version to bump\n",
+    "    unbump:bool=False):  # Reduce version instead of increasing it\n",
     "    \"Increment version in settings.ini by one\"\n",
     "    cfg = get_config()\n",
     "    print(f'Old version: {cfg.version}')\n",
-    "    cfg.d['version'] = bump_version(get_config().version, part)\n",
+    "    cfg.d['version'] = bump_version(get_config().version, part, unbump=unbump)\n",
     "    cfg.save()\n",
     "    update_version()\n",
     "    print(f'New version: {cfg.version}')"