Removed references to negative value for depth

Updated docs, Added trailing comma in cli.py

Signed-off-by: Hanif Ali <alihanif016@gmail.com>

docs/source/cli-reference/core-options.rst

@@ -126,18 +126,13 @@ Comparing Progress Message Options
 ----------------------------------
 
     Normally, the scan takes place upto the maximum level of nesting of directories possible. But
-    using the ``--max-depth`` option, the depth of the scan can be limited. This can reduce the time
-    taken for the scan when deeper directories are not relevant.
+    using the ``--max-depth`` option, you can specify the maximum level of directories to scan,
+    including and below the root location. This can reduce the time taken for the scan when deeper
+    directories are not relevant.
 
     Note that the ``--max-depth`` option will be ignored if you are scanning from a JSON file using
     the ``--from-json`` option. In that case, the original depth is used.
 
-    Some INTEGER values of the ``--max-depth INTEGER`` option:
-
-    - **4**     - Scan only upto 4 levels of subdirectories
-    - **0**     - Default, Scan upto maximum levels of subdirectories (no depth limit)
-    - **-1**    - Same effect as when set to 0
-
     An example usage::
 
         scancode -clieu --json-pp results.json samples --max-depth 3

docs/source/rst_snippets/core_options.rst

@@ -24,9 +24,9 @@ All "Core" Scan Options
                          and disable on-disk caching. Use -1 to use
                          only on-disk caching.  [Default: 10000]
 
---max-depth INTEGER      Maximum nesting of subdirectories to scan.
-                         Positive value indicates a fixed depth of scan
-                         while a negative value means no depth limit.
+--max-depth INTEGER      Descend at most INTEGER levels of directories
+                         including and below the starting point. INTEGER
+                         must be positive or zero for no limit.
                          [Default: 0]
 
 .. include::  /rst_snippets/note_snippets/core_indep.rst

src/scancode/cli.py

@@ -877,7 +877,7 @@ def echo_func(*_args, **_kwargs):
                 full_root=full_root,
                 strip_root=strip_root,
                 max_in_memory=max_in_memory,
-                max_depth=max_depth
+                max_depth=max_depth,
             )
         except:
             msg = 'ERROR: failed to collect codebase at: %(input)r' % locals()

src/scancode/resource.py

@@ -138,17 +138,12 @@ def depth_walk(root_location, max_depth, skip_ignored=lambda x: False, error_han
     # Find root directory depth using path separator's count
     root_dir_depth = root_location.count(os.path.sep)
 
-    # Default behaviour. current_depth is always less than max_depth so that 
-    # os_walk keeps running. When max_depth is limited, the current_depth is
-    # changed in each iteration and compared with max_depth
-    current_depth = -2
-
     for top, dirs, files in os_walk(root_location, topdown=True, onerror=error_handler):
-        # If depth is limited
-        if max_depth > 0:
+        # If depth is limited (non-zero)
+        if max_depth:
             current_depth = top.count(os.path.sep) - root_dir_depth
 
-        if skip_ignored(top) or current_depth >= max_depth:
+        if skip_ignored(top) or (max_depth and current_depth >= max_depth):
             # we clear out `dirs` and `files` to prevent `os_walk` from visiting
             # the files and subdirectories of directories we are ignoring or 
             # are not in the specified nesting level
@@ -285,8 +280,8 @@ def __init__(self, location,
         memory. Beyond this number, Resource are saved on disk instead. -1 means
         no memory is used and 0 means unlimited memory is used.
 
-        `max_depth` is the maximum level of nesting of subdirectories that the 
-        scan will go. A value of 0 or negative means no limit.
+        `max_depth` is the maximum depth of subdirectories to descend below and 
+        including `location`.
         """
         self.original_location = location
         self.full_root = full_root