Fixed #1

Author: flacle

README.md

@@ -12,31 +12,43 @@ Solutions that I've found online looked at changes to files irrespective whether
 *Tested with Python version 3.5.3 and Git version 2.20.1*
 
 # How it works
-This lightweight script looks at a range of commits per author. For each commit it bookkeeps the files that were changed along with the LOC for each file. LOC are kept in a sparse structure and changes per LOC are taken into account as the program loops. When a change to the same LOC is detected it updates this separately to bookkeep the true code churn.
-Result is a print with aggregated contribution and churn per author for a given time period.
+This lightweight script looks at commits per author for a given date range on the **current branch**. For each commit it bookkeeps the files that were changed along with the LOC for each file. LOC are kept in a sparse structure and changes per LOC are taken into account as the program loops. When a change to the same LOC is detected it updates this separately to bookkeep the true code churn.
+Result is a print with aggregated contribution and churn per author for a given period in time.
 
 ***Note:*** This includes the `--no-merges` flag as it assumes that merge commits with or without merge conflicts are not indicative of churn.
 
 # Usage
 Positional (required) arguments:
 - **after**        after a certain date, in YYYY[-MM[-DD]] format
 - **before**     before a certain date, in YYYY[-MM[-DD]] format
-- **author**     author string (not committer)
+- **author**     author string (not a committer), leave blank to scope all authors
 - **dir**            include Git repository directory
 
 Optional arguments:
 - **-h, --h, --help**    show this help message and exit
 - **-exdir**                   exclude Git repository subdirectory
 
-## Example
+## Usage Example 1
 ```bash
 python ./gitcodechurn.py after="2018-11-29" before="2019-03-01" author="an author" dir="/Users/myname/myrepo" -exdir="excluded-directory"
 ```
-## Output
+## Output 1
 ```bash
 author:       an author
 contribution: 844
 churn:        -28
 ```
-Outputs can be used as part of a pipeline that generates bar charts for reports:
+
+## Usage Example 2
+```bash
+python ./gitcodechurn.py after="2018-11-29" before="2019-03-01" author="" dir="/Users/myname/myrepo" -exdir="excluded-directory"
+```
+## Output 2
+```bash
+authors:      author1, author2, author3
+contribution: 4423
+churn:        -543
+```
+
+Outputs of Usage Example 1 can be used as part of a pipeline that generates bar charts for reports:
 ![contribution vs churn example chart](/chart.png)

gitcodechurn.py

@@ -8,16 +8,16 @@
 Code churn has several definitions, the one that to me provides the
 most value as a metric is:
 
-"Code churn is when an engineer
-rewrites their own code in a short period of time."
+"Code churn is when an engineer rewrites their own code in a short time period."
 
 Reference: https://blog.gitprime.com/why-code-churn-matters/
 
-This lightweight script looks at a range of commits per author. For each commit
-it book-keeps the files that were changed along with the lines of code (LOC)
-for each file. LOC are kept in a sparse structure and changes per LOC are taken
-into account as the program loops. When a change to the same LOC is detected it
-updates this separately to bookkeep the true code churn.
+This lightweight script looks at commits per author for a given date range on
+the default branch. For each commit it bookkeeps the files that were changed
+along with the lines of code (LOC) for each file. LOC are kept in a sparse
+structure and changes per LOC are taken into account as the program loops. When
+a change to the same LOC is detected it updates this separately to bookkeep the
+true code churn.
 
 Result is a print with aggregated contribution and churn per author for a
 given time period.
@@ -41,30 +41,30 @@ def main():
     parser.add_argument(
         'after',
         type = str,
-        help = 'after a certain date, in YYYY[-MM[-DD]] format'
+        help = 'search after a certain date, in YYYY[-MM[-DD]] format'
     )
     parser.add_argument(
         'before',
         type = str,
-        help = 'before a certain date, in YYYY[-MM[-DD]] format'
+        help = 'search before a certain date, in YYYY[-MM[-DD]] format'
     )
     parser.add_argument(
         'author',
         type = str,
-        help = 'author string (not committer)'
+        help = 'an author (non-committer), leave blank to scope all authors'
     )
     parser.add_argument(
         'dir',
         type = dir_path,
         default = '',
-        help = 'include Git repository directory'
+        help = 'the Git repository root directory to be included'
     )
     parser.add_argument(
         '-exdir',
         metavar='',
         type = str,
         default = '',
-        help = 'exclude Git repository subdirectory'
+        help = 'the Git repository subdirectory to be excluded'
     )
     args = parser.parse_args()
 
@@ -100,7 +100,13 @@ def main():
             exdir
         )
 
-    print('author: \t', author)
+    # if author is empty then print a unique list of authors
+    if len(author.strip()) == 0:
+        authors = set(get_commits(before, after, author, dir, '%an')).__str__()
+        authors = authors.replace('{', '').replace('}', '').replace("'","")
+        print('authors: \t', authors)
+    else:
+        print('author: \t', author)
     print('contribution: \t', contribution)
     print('churn: \t\t', -churn)
     # print files in case more granular results are needed
@@ -139,8 +145,9 @@ def get_loc(commit, dir, files, contribution, churn, exdir):
                 continue
     return [files, contribution, churn]
 
-# arrives in a format such as -13 +27,5 (no decimals == 1 loc change)
-# returns a dictionary where left are removals and right are additions
+# arrives in a format such as -13 +27,5 (no commas mean 1 loc change)
+# this is the chunk header where '-' is old and '+' is new
+# it returns a dictionary where left are removals and right are additions
 # if the same line got changed we subtract removals from additions
 def get_loc_change(loc_changes):
     # removals
@@ -186,12 +193,11 @@ def is_new_file(result, file):
     else:
         return file
 
-def get_commits(before, after, author, dir):
+# use format='%an' to get a list of author names
+def get_commits(before, after, author, dir, format='%h'):
     # note --no-merges flag (usually we coders do not overhaul contrib commits)
     # note --reverse flag to traverse history from past to present
-    before = format_date(before)
-    after = format_date(after)
-    command = 'git log --author="'+author+'" --format="%h" --no-abbrev '
+    command = 'git log --author="'+author+'" --format="'+format+'" --no-abbrev '
     command += '--before="'+before+'" --after="'+after+'" --no-merges --reverse'
     return get_proc_out(command, dir).splitlines()