From pgsql-hackers-owner+M16120=candle.pha.pa.us=pgman@postgresql.org Fri Nov 30 12:14:19 2001 Return-path: Received: from rs.postgresql.org (server1.pgsql.org [64.39.15.238] (may be forged)) by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id fAUIEIR21802 for ; Fri, 30 Nov 2001 13:14:18 -0500 (EST) Received: from postgresql.org (postgresql.org [64.49.215.8]) by rs.postgresql.org (8.11.6/8.11.6) with ESMTP id fAUI6ER13094 for ; Fri, 30 Nov 2001 12:11:00 -0600 (CST) (envelope-from pgsql-hackers-owner+M16120=candle.pha.pa.us=pgman@postgresql.org) Received: from moutvdom01.kundenserver.de (moutvdom01.kundenserver.de [195.20.224.200]) by postgresql.org (8.11.3/8.11.4) with ESMTP id fAUI58m98870 for ; Fri, 30 Nov 2001 13:05:08 -0500 (EST) (envelope-from peter_e@gmx.net) Received: from [195.20.224.208] (helo=mrvdom01.schlund.de) by moutvdom01.kundenserver.de with esmtp (Exim 2.12 #2) id 169s27-00049P-00 for pgsql-hackers@postgresql.org; Fri, 30 Nov 2001 19:05:07 +0100 Received: from p3e9e6fa2.dip0.t-ipconnect.de ([62.158.111.162]) by mrvdom01.schlund.de with esmtp (Exim 2.12 #2) id 169s21-0001UP-00 for pgsql-hackers@postgresql.org; Fri, 30 Nov 2001 19:05:03 +0100 Date: Fri, 30 Nov 2001 19:12:16 +0100 (CET) From: Peter Eisentraut X-Sender: To: PostgreSQL Development Subject: [HACKERS] Backend error message style issues Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Status: ORr Now that we've gone through nearly one development cycle with national language support, I'd like to bring up a number of issues concerning the style of the backend error messages that make life difficult, but probably not only for the translators but for users as well. Not all of these are strictly translation issues, but the message catalogs make for a good overview of what's going on. I hope we can work through all of these during the next development period. Prefixing messages with command names ------------------------------------- For instance, | CREATE DATABASE: permission denied This "command: message" style is typical for command-line programs and it's pretty useful there if you run many commands in a pipe. The same usefulness could probably be derived if you run many SQL commands in a function. (Just "permission denied" would be very confusing there!) If we want to use that style we should make it consistent and we should automate it. Via the "command tag" mechanism we already know what command we're executing, so we can automatically prefix all messages that way. It could even be switched off by the user if it's deemed annoying. Prefixing messages with function names -------------------------------------- The function names obviously have no meaning to the user. It is claimed that they allow a developer to locate the place the error was raised faster, but that's only half the truth. Firstly, this whole thing doesn't work if the displayed name of the function was actually passed in from elsewhere. Then it takes you three times longer to locate the source because you *think* you know where it was but it's not there. Secondly, a developer doesn't have the need to locate every error. For instance, | ExecAppend: rejected due to CHECK constraint foo There's no need to debug anything there, it's a perfectly normal use situation. I think the key here is to distinguish error messages that are perfectly normal user-level events from messages which really represent an "assert failure, but continue gracefully", such as | initGISTstate: numberOfAttributes %d > %d The latter could better be written something like | BETTER_BE_TRUE(index->rd_att->natts > INDEX_MAX_KEYS); we could lead to an error message in the style of an assert failure, including the expression in question and file and line information (and bug reporting suggestions). This way the developer doesn't have to write any message text at all but still gets much better information to locate the source. (E.g., note that the tested variable isn't even called "numberOfAttributes".) The exact API could be tuned to include some other information such as an informal message, but I think something along these lines needs to be worked out. Quoting ------- Which is better: function '%s' not found function "%s" not found function %s not found I think two kinds of quotes is looking messy. Personal suggestion: double quotes. Capitalization and punctuation ------------------------------ Which one? ERROR: Permission denied. ERROR: Permission denied ERROR: permission denied I have personally used the GNU-recommended way which is the third, mostly just because it is *some* standardized way. I don't have a strong feeling about the initial capitalization, but I'm against the periods except when the message is really a sentence and it contains some other punctuation (commas, etc.) or the message consists of more than one sentence. Grammatical structure and choice of words ----------------------------------------- There are many others besides the above choices: ERROR: Permission was denied. ERROR: You don't have permission to do . ERROR: Permission to do was denied. ERROR: : Permission denied In other cases there's a sea of possibilities: couldn't find THING can't find THING THING wasn't found unable to locate THING lookup of THING failed THING doesn't exist Strictly speaking, there are at least four different meanings among those six messages, yet they're used mostly randomly. There are a number of things to think about here: active vs passive, can vs could, complete sentence vs telegram style, use of colons, addressing the user with "you [cannot...]". And please let's not have the program talk in the "I"-form ("I have rolled back the current transaction ..."). More esoteric discussions are also possible, but I'm going to postpone those. ;-) However, I think it's worth working on this and perhaps putting together a "manual of style" that applies to all parts of PostgreSQL. This would significantly improve the overall perceived quality. Some projects like KDE, GNU, and GCC have teams that discuss these kinds of things and it's definitely showing. -- Peter Eisentraut peter_e@gmx.net ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@postgresql.org so that your message can get through to the mailing list cleanly From pgsql-hackers-owner+M16128=candle.pha.pa.us=pgman@postgresql.org Fri Nov 30 13:39:41 2001 Return-path: Received: from rs.postgresql.org (server1.pgsql.org [64.39.15.238] (may be forged)) by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id fAUJdfR29066 for ; Fri, 30 Nov 2001 14:39:41 -0500 (EST) Received: from postgresql.org (postgresql.org [64.49.215.8]) by rs.postgresql.org (8.11.6/8.11.6) with ESMTP id fAUJXkR15701 for ; Fri, 30 Nov 2001 13:36:17 -0600 (CST) (envelope-from pgsql-hackers-owner+M16128=candle.pha.pa.us=pgman@postgresql.org) Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) by postgresql.org (8.11.3/8.11.4) with ESMTP id fAUJMnm01940 for ; Fri, 30 Nov 2001 14:22:49 -0500 (EST) (envelope-from mascarm@mascari.com) Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id OAA20637; Fri, 30 Nov 2001 14:16:52 -0500 Message-ID: <3C07DBAD.A9735975@mascari.com> Date: Fri, 30 Nov 2001 14:19:09 -0500 From: Mike Mascari Organization: Mascari Development Inc. X-Mailer: Mozilla 4.77 [en] (WinNT; U) X-Accept-Language: en MIME-Version: 1.0 To: Peter Eisentraut cc: PostgreSQL Development Subject: Re: [HACKERS] Backend error message style issues References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Status: OR Peter Eisentraut wrote: > > Now that we've gone through nearly one development cycle with national > language support, I'd like to bring up a number of issues concerning the > style of the backend error messages that make life difficult, but probably > not only for the translators but for users as well. Not all of these are > strictly translation issues, but the message catalogs make for a good > overview of what's going on. For what its worth, Oracle 8 ships with an error.txt file which dictates the message standards to which their products comply. Roughly: Size Of Message: --------------- Cannot exceed 76 characters, even when embedded format specifiers are apart of the message. Only start-up and system-dependent messages can exceed 76 characters. Simple Language: --------------- Use non-cryptic messages and overly technical language. Upper vs. Lowercase: ------------------- Use uppercase for commands and keywords, lowercase for message wording, including the first letter (which agrees with your use, Peter). Commands, Keywords, Parameter Values: ------------------------------------ When possible, give the command, keyword and parameters used in the message. BAD: The relation could not be created GOOD: CREATE TABLE failed for table "foo" because the disk is full Period: ------ Do not end messages with a period (also agrees with your conclusion). Numbers: ------- Don't enclose numbers with special characters. For example: BAD: rows returned by subquery (3) exceeded limit (1) GOOD: the subquery returned 3 rows exceeding the 1 row limit Quotes: ------ Don't use single or double quotes to emphasize a text variable or command Single Quotes: ------------- Never use them. Double Quotes: ------------- Always and only use them to identify database objects. BAD: Unable to drop table employees GOOD: DROP TABLE of "employees" failed due to referential integrity constraints Ellipses: -------- Don't use them. BAD: Unable to drop column mascarm.employees.salary GOOD: ALTER TABLE was unable to drop the column "salary" table "employees" schema "mascarm" Parentheses: ----------- Always and only use parentheses for constraint names BAD: not null constraint ri_employees violated GOOD: not null constraint (ri_employees) violated Brackets: -------- Always and only used for program arguments Grammar: ------- Use complete sentences whenever possible without the trailing period. Don't use multiple sentences. Use the active voice. Don't use an aggressive tone. Style: ----- Make positive suggestions. Explain what is invalid and what is valid. Example: BAD: file name invalid BETTER: COPY failed because the file name was too long Routine names: ------------- Do not use routine names in messages. Again, agrees with you, Peter. FWIW, Mike Mascari mascarm@mascari.com ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org From pgsql-hackers-owner+M16130=candle.pha.pa.us=pgman@postgresql.org Fri Nov 30 14:09:48 2001 Return-path: Received: from rs.postgresql.org (server1.pgsql.org [64.39.15.238] (may be forged)) by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id fAUK9lR02095 for ; Fri, 30 Nov 2001 15:09:48 -0500 (EST) Received: from postgresql.org (postgresql.org [64.49.215.8]) by rs.postgresql.org (8.11.6/8.11.6) with ESMTP id fAUK3MR16820 for ; Fri, 30 Nov 2001 14:05:48 -0600 (CST) (envelope-from pgsql-hackers-owner+M16130=candle.pha.pa.us=pgman@postgresql.org) Received: from sss.pgh.pa.us ([192.204.191.242]) by postgresql.org (8.11.3/8.11.4) with ESMTP id fAUJnLm02954 for ; Fri, 30 Nov 2001 14:49:21 -0500 (EST) (envelope-from tgl@sss.pgh.pa.us) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.11.4/8.11.4) with ESMTP id fAUJnEi10307; Fri, 30 Nov 2001 14:49:14 -0500 (EST) To: Peter Eisentraut cc: PostgreSQL Development Subject: Re: [HACKERS] Backend error message style issues In-Reply-To: References: Comments: In-reply-to Peter Eisentraut message dated "Fri, 30 Nov 2001 19:12:16 +0100" Date: Fri, 30 Nov 2001 14:49:14 -0500 Message-ID: <10303.1007149754@sss.pgh.pa.us> From: Tom Lane Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org Status: OR Peter Eisentraut writes: > I hope we can work through all of these during the next development > period. Too bad we didn't do it *before* doing a lot of translation work :-(. Yes, I agree that a pass of rationalizing the error messages would be useful. Might want to think about that old bugaboo, error codes, while we're at it. Also the perennial complaint that "ERROR" and "DEBUG" macros tend to conflict with other things. As long as we're going to touch many/all of the elog() calls, couldn't we try to clean up all these issues? > Which is better: > function '%s' not found > function "%s" not found > function %s not found Given that 'x' and "x" mean very different things in SQL, I think that the first form is just plain wrong when an identifier is involved. Unfortunately a lot of older code uses that style. I've tried to use double quotes in new messages, but have restrained myself from wholesale changes of existing messages. > More esoteric discussions are also possible, but I'm going to postpone > those. ;-) However, I think it's worth working on this and perhaps > putting together a "manual of style" that applies to all parts of > PostgreSQL. This would significantly improve the overall perceived > quality. Sounds like a plan to me: put together a style guide first, and then make a pass through the code to try to implement it. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org