Disable cache by default, enable it by mbed config -G cache on

Author: screamerbg

README.md

@@ -781,7 +781,7 @@ Here is a list of currently implemented configuration settings:
  * `ARM_PATH`, `GCC_ARM_PATH`, `IAR_PATH` - defines the default path to ARM Compiler, GCC ARM and IAR Workbench toolchains. Default: none.
  * `protocol` - defines the default protocol used for importing or cloning of programs and libraries. The possible values are `https`, `http` and `ssh`. Use `ssh` if you have generated and registered SSH keys (Public Key Authentication) with a service like GitHub, GitLab, Bitbucket, etc. Read more about SSH keys [here](https://help.github.com/articles/generating-an-ssh-key/) Default: `https`.
  * `depth` - defines the *clone* depth for importing or cloning and applies only to *Git* repositories. Note that while this option may improve cloning speed, it may also prevent you from correctly checking out a dependency tree when the reference revision hash is older than the clone depth. Read more about shallow clones [here](https://git-scm.com/docs/git-clone). Default: none.
- * `cache` - defines the local path that will be used to store minimalistic copies of the imported or cloned repositories, and attempts to use them to minimize traffic and speed up future importing. Will disable caching if set to "off" or "none". Default: system temp path.
+ * `cache` - defines the local path that will be used to store minimalistic copies of the imported or cloned repositories, and attempts to use it to minimize traffic and speed up future imports of the same repositories. Use `on` or `enabled` to turn on caching in the system temp path. Default: none (disabled).
 
 ## Troubleshooting
 

mbed/mbed.py

@@ -850,7 +850,7 @@ def fromurl(cls, url, path=None):
             error('Invalid repository (%s)' % url.strip(), -1)
 
         cache_cfg = Global().get_cfg('CACHE', '')
-        if cache_repositories and cache_cfg != 'none' and cache_cfg != 'off' and cache_cfg != 'disabled':
+        if cache_repositories and cache_cfg and cache_cfg != 'none' and cache_cfg != 'off' and cache_cfg != 'disabled':
             loc = cache_cfg if (cache_cfg and cache_cfg != 'on' and cache_cfg != 'enabled') else None
             repo.cache = loc or os.path.join(tempfile.gettempdir(), 'mbed-repo-cache')
 
@@ -885,7 +885,7 @@ def fromrepo(cls, path=None):
         repo.name = os.path.basename(repo.path)
 
         cache_cfg = Global().get_cfg('CACHE', '')
-        if cache_repositories and cache_cfg != 'none' and cache_cfg != 'off' and cache_cfg != 'disabled':
+        if cache_repositories and cache_cfg and cache_cfg != 'none' and cache_cfg != 'off' and cache_cfg != 'disabled':
             loc = cache_cfg if (cache_cfg and cache_cfg != 'on' and cache_cfg != 'enabled') else None
             repo.cache = loc or os.path.join(tempfile.gettempdir(), 'mbed-repo-cache')
 
@@ -1203,7 +1203,7 @@ def __init__(self, path=None, print_warning=False):
         if self.is_cwd and print_warning:
             warning(
                 "Could not find mbed program in current path \"%s\".\n"
-                "You can fix this by calling \"mbed new .\" or \"mbed config root .\" in the root of your program." % self.path)
+                "You can fix this by calling \"mbed new .\" in the root of your program." % self.path)
 
     def get_cfg(self, *args, **kwargs):
         return Cfg(self.path).get(*args, **kwargs) or Global().get_cfg(*args, **kwargs)
@@ -2379,6 +2379,10 @@ def config_(var=None, value=None, global_cfg=False, unset=False, list_config=Fal
         else:
             # Find the root of the program
             program = Program(os.getcwd())
+            if program.is_cwd:
+                error(
+                    "Could not find mbed program in current path \"%s\".\n"
+                    "Change the current directory to a valid mbed program or use the '--global' option to set global configuration." % program.path)
             with cd(program.path):
                 if unset:
                     program.set_cfg(var, None)