changeset 41761:e2472b12c842

contrib: enforce wrapping too-long lines with () instead of \

This is the style I prefer, and an anecdotal exploration of styles
recommended in style guides etc. Further, to quote pep8:

> The preferred way of wrapping long lines is by using Python's implied
> line continuation inside parentheses, brackets and braces. Long lines
> can be broken over multiple lines by wrapping expressions in
> parentheses. These should be used in preference to using a backslash
> for line continuation.

So I think this is a virtuous change.

Differential Revision: https://phab.mercurial-scm.org/D5995

--- a/contrib/check-code.py	Wed Feb 20 18:02:28 2019 -0500
+++ b/contrib/check-code.py	Sun Jan 13 20:27:00 2019 -0500
@@ -233,6 +233,7 @@
 
 pypats = [
   [
+    (r'\\$', 'Use () to wrap long lines in Python, not \\'),
     (r'^\s*def\s*\w+\s*\(.*,\s*\(',
      "tuple parameter unpacking not available in Python 3+"),
     (r'lambda\s*\(.*,.*\)',

--- a/tests/test-contrib-check-code.t	Wed Feb 20 18:02:28 2019 -0500
+++ b/tests/test-contrib-check-code.t	Sun Jan 13 20:27:00 2019 -0500
@@ -7,6 +7,9 @@
   > def toto( arg1, arg2):
   >     del(arg2)
   >     return ( 5+6, 9)
+  > def badwrap():
+  >     return 1 + \\
+  >        2
   > NO_CHECK_EOF
   $ cat > quote.py <<NO_CHECK_EOF
   > # let's use quote in comments
@@ -42,6 +45,9 @@
    >     return ( 5+6, 9)
    gratuitous whitespace in () or []
    missing whitespace in expression
+  ./wrong.py:5:
+   >     return 1 + \
+   Use () to wrap long lines in Python, not \
   ./quote.py:5:
    > '"""', 42+1, """and
    missing whitespace in expression