Add ability to exclude files like black's extend-exclude option

[fizbin]

Short version: if I exclude files from being formatted with black's extend-exclude option in pyproject.toml, then darker should also not touch those files.

Longer version:

Consider a repo with three files in it:

testproj $ cat pyproject.toml 
[tool.black]
line-length = 100
target-version = ['py36']
extend-exclude = '''
DontReformatMe.py  # Put generated code in files named this
'''

[tool.darker]
line-length = 100
src = [
    ".",
]
revision = "main..."
extend-exclude = '''
DontReformatMe.py  # Put generated code in files named this
'''

testproj $ cat ReformatMe.py 
import sys

if len(sys.argv) >= 2:
    if sys.argv[1] == 'cat':
        print('meow')
testproj $ cat DontReformatMe.py 
import sys

if len(sys.argv) >= 2:
    if sys.argv[1] == 'cat':
        print('kitten')

Now do a git add * and git commit -m 'Initial commit', followed by black . and git commit -a -m 'Reformatted with black'. Now imagine that the time comes to add canine support to these files, so after making this obvious changes, you run darker before committing.

Now look as what git diff says:

testproj dtm$ git diff
diff --git a/DontReformatMe.py b/DontReformatMe.py
index d131e58..93d0c5f 100644
--- a/DontReformatMe.py
+++ b/DontReformatMe.py
@@ -1,5 +1,7 @@
 import sys
 
 if len(sys.argv) >= 2:
-    if sys.argv[1] == 'cat':
-        print('kitten')
+    if sys.argv[1] == "cat":
+        print("kitten")
+    if sys.argv[1] == "dog":
+        print("puppy")
diff --git a/ReformatMe.py b/ReformatMe.py
index 07f3639..f5f34cc 100644
--- a/ReformatMe.py
+++ b/ReformatMe.py
@@ -3,3 +3,5 @@ import sys
 if len(sys.argv) >= 2:
     if sys.argv[1] == "cat":
         print("meow")
+    elif sys.argv[1] == "dog":
+        print("woof")

Behold, darker has gone and reformatted the file called DontReformatMe.py, exactly as we told black not to. (And indeed, black won't touch the file if asked to reformat everything)

[akaihola]

I believe this has already been reported in #146 and fixed in #171, and this will be included in the upcoming 1.3.0 release. Could you try installing the development version from the master branch and verify that it behaves correctly?

Here's how to install from master:

pip install git+https://github.com/akaihola/darker.git@master

[akaihola]

@fizbin, this feature has now been released in Black 1.3.0. Does this fulfill what you needed?

[akaihola]

I tried out @fizbin's original example using Darker 1.3.2, and it did not reformat DontReformatMe.py. It seems version 1.3.0 fixed this problem, so I'm closing this issue now.

[brtkwr]

Hmm I cant get it to work unfortunately. I added the following into my pyproject.toml file:

[tool.black]
extend-exclude = '''
^/src/alembic/versions/*.py
src/alembic/versions/20211210_154740_679ff6652fc6_merged_initial_prod_db.py
'''
[tool.darker]
extend-exclude = '''
^/src/alembic/versions/*.py
src/alembic/versions/20211210_154740_679ff6652fc6_merged_initial_prod_db.py
'''

If I run black --check, I notice that the files get ignored but doesnt seem to be getting ignored by darker somehow.