Exception Messages End with Newline

[archuserr]

It looks like all the exception messages end with a newline char. That's inconsistent with both the Python standard library and all the third-party libraries I've worked with.

I searched the psycopg python files and didn't find the error messages, so I assume those (and the newline) come from the Postgres library.

I solved the problem by adding [:-1] to the exception messages. Would it make sense to make that change in psycopg?

[dvarrazzo]

It may make sense or not. The messages are multiline: if they were a single line I would agree with you, but being multiline it's a bit like a file: some conventions assume a final newline, some don't.

try:
    cur.execute("select noway")
except Exception as e:
    pass

str(e)
'column "noway" does not exist\nLINE 1: select noway\n               ^\n'

Maybe if I started the library from scratch I would strip these, and maybe I wouldn't even use the entire message but only the primary.

e.diag.message_primary
'column "noway" does not exist'

However now there is code used to the trailing whiteline written since the last century: I don't feel like changing this in a backward-compatible library. So I guess it's a thing for a mythical psycopg3.

One remark: your solution is brittle: if we "fixed" psycopg you would start chopping the last character of the message - and this is the exact reason why I don't want to change this behaviour out of the blue. I advise you to use .rstrip() instead.

[dvarrazzo]

Psycopg3 uses the message_primary.