Re: ICU for global collation

On 2022-09-21 17:53, Peter Eisentraut wrote:
> Committed with that test, thanks.  I think that covers all the ICU
> issues you reported for PG15 for now?

I thought about the order of the ICU checks - if it is ok to check that 
the selected encoding is supported by ICU after printing all the locale 
& encoding information, why not to move almost all the ICU checks 
here?..

Examples of the work of the attached patch:

1. ICU locale vs supported encoding:

1.1.

$ initdb --encoding sql-ascii --locale-provider icu hoge
...
initdb: error: encoding mismatch
initdb: detail: The encoding you selected (SQL_ASCII) is not supported 
with the ICU provider.
initdb: hint: Rerun initdb and either do not specify an encoding 
explicitly, or choose a matching combination.

1.2. (like before)

$ initdb --encoding sql-ascii --icu-locale en-US hoge
initdb: error: --icu-locale cannot be specified unless locale provider 
"icu" is chosen

$ createdb --encoding sql-ascii --icu-locale en-US hoge
createdb: error: database creation failed: ERROR:  ICU locale cannot be 
specified unless locale provider is ICU

2. For builds without ICU:

2.1.

$ initdb --locale-provider icu hoge
...
initdb: error: ICU is not supported in this build

$ createdb --locale-provider icu hoge
createdb: error: database creation failed: ERROR:  ICU is not supported 
in this build

2.2. (like before)

$ initdb --icu-locale en-US hoge
initdb: error: --icu-locale cannot be specified unless locale provider 
"icu" is chosen

$ createdb --icu-locale en-US hoge
createdb: error: database creation failed: ERROR:  ICU locale cannot be 
specified unless locale provider is ICU

2.3.

$ createdb --locale-provider icu --icu-locale en-US --encoding sql-ascii 
hoge
createdb: error: database creation failed: ERROR:  ICU is not supported 
in this build

4. About errors in initdb:

4.1. If icu_locale is not specified, but it is required, then we get 
this:

$ initdb --locale-provider icu hoge
The files belonging to this database system will be owned by user 
"marina".
This user must also own the server process.

The database cluster will be initialized with this locale configuration:
   provider:    icu
   LC_COLLATE:  en_US.UTF-8
   LC_CTYPE:    en_US.UTF-8
   LC_MESSAGES: en_US.UTF-8
   LC_MONETARY: ru_RU.UTF-8
   LC_NUMERIC:  ru_RU.UTF-8
   LC_TIME:     ru_RU.UTF-8
The default database encoding has been set to "UTF8".
initdb: error: ICU locale must be specified

Almost the same if ICU is not supported in this build:

$ initdb --locale-provider icu hoge
The files belonging to this database system will be owned by user 
"marina".
This user must also own the server process.

The database cluster will be initialized with this locale configuration:
   provider:    icu
   LC_COLLATE:  en_US.UTF-8
   LC_CTYPE:    en_US.UTF-8
   LC_MESSAGES: en_US.UTF-8
   LC_MONETARY: ru_RU.UTF-8
   LC_NUMERIC:  ru_RU.UTF-8
   LC_TIME:     ru_RU.UTF-8
The default database encoding has been set to "UTF8".
initdb: error: ICU is not supported in this build

4.2. If icu_locale is specified for the wrong provider, the error will 
be at the beginning of the program start as before:

$ initdb --icu-locale en-US hoge
initdb: error: --icu-locale cannot be specified unless locale provider 
"icu" is chosen

-- 
Marina Polyakova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company