Black fails for some long lines.

[exhuma]

Describe the bug

For some very long lines, black bails out with the error:

error: cannot format foo.py: INTERNAL ERROR: Black produced different code on the second pass of the formatter.  Please report a bug on https://github.com/psf/black/issues.  This diff might be helpful: /tmp/blk_e7p5_wy5.log

To Reproduce Steps to reproduce the behavior:

1. Take this file '...'

class MyLongClassName:
    LONG_NAME_1 = "foo"
    LONG_NAME_2 = "bar"

    def __init__(self, value):
        if value not in (MyLongClassName.LONG_NAME_2, MyLongClassName.LONG_NAME_1) and not isinstance(
            value, int
        ):
            pass

2. Run Black on it with these arguments

black -l 80 foo.py

3. See error

    error: cannot format foo.py: INTERNAL ERROR: Black produced different code on the second pass of the formatter.  Please report a bug on https://github.com/psf/black/issues.  This diff might be helpful: /tmp/blk_e7p5_wy5.log

Expected behavior

No error should appear

Environment (please complete the following information):

• Version: 20.8b1
• OS and Python version: e.g. Linux/Python 3.6.9

Does this bug also happen on master? yes

Additional context

The following file works:

class Foo:
    LONG_NAME_1 = "foo"
    LONG_NAME_2 = "bar"

    def __init__(self, value):
        if value not in (Foo.LONG_NAME_2, Foo.LONG_NAME_1) and not isinstance(
            value, int
        ):
            pass

Log File /tmp/blk_e7p5_wy5.log

Mode(target_versions=set(), line_length=80, string_normalization=True, experimental_string_processing=False, is_pyi=False)
--- source
+++ first pass
@@ -1,9 +1,10 @@
 class MyLongClassName:
     LONG_NAME_1 = "foo"
     LONG_NAME_2 = "bar"

     def __init__(self, value):
-        if value not in (MyLongClassName.LONG_NAME_2, MyLongClassName.LONG_NAME_1) and not isinstance(
-            value, int
-        ):
+        if value not in (
+            MyLongClassName.LONG_NAME_2,
+            MyLongClassName.LONG_NAME_1,
+        ) and not isinstance(value, int):
             pass
--- first pass
+++ second pass
@@ -1,10 +1,14 @@
 class MyLongClassName:
     LONG_NAME_1 = "foo"
     LONG_NAME_2 = "bar"

     def __init__(self, value):
-        if value not in (
-            MyLongClassName.LONG_NAME_2,
-            MyLongClassName.LONG_NAME_1,
-        ) and not isinstance(value, int):
+        if (
+            value
+            not in (
+                MyLongClassName.LONG_NAME_2,
+                MyLongClassName.LONG_NAME_1,
+            )
+            and not isinstance(value, int)
+        ):
             pass

[exhuma]

In case someone runs into this issue as well, I fenced it with # fmt: off and # fmt: on as a workaround for now.

[lodagro]

Similar situation, input is only one (very long) line of code.

 x = "%s   %s        %s                                        %s %s %s      %s        %s %s" % (a_very_long,b_very_long,c_very_long,d_very_long,e_very_long,f_very_long,g_very_long,h_very_long,i_very_long) 

  1 Mode(target_versions=set(), line_length=88, string_normalization=1, experimental_string_processing=False, is_pyi=False)                                                                                                                                                                                                  
    2 --- source                                                                                                                                                                                                                                                                                                               
    3 +++ first pass                                                                                                                                                                                                                                                                                                           
    4 @@ -1 +1,14 @@                                                                                                                                                                                                                                                                                                           
    5 -x = "%s   %s        %s                                        %s %s %s      %s        %s %s" % (a_very_long,b_very_long,c_very_long,d_very_long,e_very_long,f_very_long,g_very_long,h_very_long,i_very_long)                                                                                                            
    6 +x = (                                                                                                                                                                                                                                                                                                                   
    7 +    "%s   %s        %s                                        %s %s %s      %s        %s %s"                                                                                                                                                                                                                            
    8 +    % (                                                                                                                                                                                                                                                                                                                 
    9 +        a_very_long,                                                                                                                                                                                                                                                                                                    
   10 +        b_very_long,                                                                                                                                                                                                                                                                                                    
   11 +        c_very_long,                                                                                                                                                                                                                                                                                                    
   12 +        d_very_long,                                                                                                                                                                                                                                                                                                    
   13 +        e_very_long,                                                                                                                                                                                                                                                                                                    
   14 +        f_very_long,                                                                                                                                                                                                                                                                                                    
   15 +        g_very_long,                                                                                                                                                                                                                                                                                                    
   16 +        h_very_long,                                                                                                                                                                                                                                                                                                    
   17 +        i_very_long,                                                                                                                                                                                                                                                                                                    
   18 +    )                                                                                                                                                                                                                                                                                                                   
   19 +)                                                                                                                                                                                                                                                                                                                       
   20 --- first pass                                                                                                                                                                                                                                                                                                           
   21 +++ second pass                                                                                                                                                                                                                                                                                                          
   22 @@ -1,14 +1,11 @@                                                                                                                                                                                                                                                                                                        
   23 -x = (                                                                                                                                                                                                                                                                                                                   
   24 -    "%s   %s        %s                                        %s %s %s      %s        %s %s"                                                                                                                                                                                                                            
   25 -    % (                                                                                                                                                                                                                                                                                                                 
   26 -        a_very_long,                                                                                                                                                                                                                                                                                                    
   27 -        b_very_long,                                                                                                                                                                                                                                                                                                    
   28 -        c_very_long,                                                                                                                                                                                                                                                                                                    
   29 -        d_very_long,                                                                                                                                                                                                                                                                                                    
   30 -        e_very_long,                                                                                                                                                                                                                                                                                                    
   31 -        f_very_long,                                                                                                                                                                                                                                                                                                    
   32 -        g_very_long,                                                                                                                                                                                                                                                                                                    
   33 -        h_very_long,                                                                                                                                                                                                                                                                                                    
   34 -        i_very_long,                                                                                                                                                                                                                                                                                                    
   35 -    )                                                                                                                                                                                                                                                                                                                   
   36 +x = "%s   %s        %s                                        %s %s %s      %s        %s %s" % (                                                                                                                                                                                                                        
   37 +    a_very_long,                                                                                                                                                                                                                                                                                                        
   38 +    b_very_long,                                                                                                                                                                                                                                                                                                        
   39 +    c_very_long,                                                                                                                                                                                                                                                                                                        
   40 +    d_very_long,                                                                                                                                                                                                                                                                                                        
   41 +    e_very_long,                                                                                                                                                                                                                                                                                                        
   42 +    f_very_long,                                                                                                                                                                                                                                                                                                        
   43 +    g_very_long,                                                                                                                                                                                                                                                                                                        
   44 +    h_very_long,                                                                                                                                                                                                                                                                                                        
   45 +    i_very_long,                                                                                                                                                                                                                                                                                                        
   46  )                                        

INTERNAL ERROR: Black produced different code on the second pass of the formatter.

• Version: 20.8b1
• OS and Python version: Linux/Python 3.8

Also occurs on master

[ichard26]

Hello!

All reproduction cases in this issue format without error on master. The fixing commit was 8672af3 from PR GH-2126. I'll be marking this issue as a duplicate of GH-1629 since that's what GH-2126 aimed to fix and it's highly likely this issue falls under GH-1629.

Since we use the issue tracker as a reflection of what's on master, I'll be closing this issue. If you have any issues, especially with the new (but stable) output, please open a new issue.

Thank you for reporting!