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digitalmars.D.learn - is collectException working for every exceptions ?

reply Roman Sztergbaum <rmscastle gmail.com> writes:
Hello as the subject say i'm asking this question because with 
the following code

```
private config_create_answer create_config(string[] args)
     in
     {
         assert(args !is null, "args cannot be null");
         assert(args.length == 2, "need 1 arguments");
     }
     out (r)
     {
         assert(r.state == "SUCCESS", "create_config should 
success");
         assert(!r.config_key.empty, "config_key should not be 
empty");
         assert(!r.readonly_config_key.empty, "readonly_config_key 
should not be empty");
     }
     body
     {
         string config_name;
         getopt(args, "name", &config_name);
         auto cfg = (cast(const 
char[])(std.file.read("../API_doc/json_recipes/config_create.json")))
             .deserialize!config_create;
         cfg.config_name = config_name.strip("\"");
         client_.socket.send(cfg.serializeToJson);
         auto answer = new ubyte[256];
         client_.socket.receive(answer);
         client_.socket.getErrorText.writeln;
         return (cast(string) 
answer).deserialize!config_create_answer;
     }

     unittest
     {
         import std.exception : collectException;

         auto cli = new CLI("/tmp/raven-os_service_albinos.sock");
         assert(cli.create_config(["create_config", "--name=toto"])
                 .state == "SUCCESS", "should be success");
         assert(cli.create_config(["create_config", 
"--name=\"titi\""])
                 .state == "SUCCESS", "should be success");
         
assert(collectException(cli.create_config(["create_config", 
"--name="]))); //here is my problem
     }
```

i would like to specify `collectException!GetOptException`, but 
it's seem's make the program exit with fail status.

any idea what i'm doing wrong ?

also it's my first d program, so if anything seem's bad let me 
know
Mar 18 2019
next sibling parent Roman Sztergbaum <rmscastle gmail.com> writes:
On Monday, 18 March 2019 at 18:54:22 UTC, Roman Sztergbaum wrote:

 Hello as the subject say i'm asking this question because with 
 the following code

 [...]


I'm asking myself if it's usefull to write unittest with contract 
programming also, but this is another subject i think
Mar 18 2019
prev sibling next sibling parent Andre Pany <andre s-e-a-p.de> writes:
On Monday, 18 March 2019 at 18:54:22 UTC, Roman Sztergbaum wrote:

 Hello as the subject say i'm asking this question because with 
 the following code

 ```
 private config_create_answer create_config(string[] args)
     in
     {
         assert(args !is null, "args cannot be null");
         assert(args.length == 2, "need 1 arguments");
     }
     out (r)
     {
         assert(r.state == "SUCCESS", "create_config should 
 success");
         assert(!r.config_key.empty, "config_key should not be 
 empty");
         assert(!r.readonly_config_key.empty, 
 "readonly_config_key should not be empty");
     }
     body
     {
         string config_name;
         getopt(args, "name", &config_name);
         auto cfg = (cast(const 
 char[])(std.file.read("../API_doc/json_recipes/config_create.json")))
             .deserialize!config_create;
         cfg.config_name = config_name.strip("\"");
         client_.socket.send(cfg.serializeToJson);
         auto answer = new ubyte[256];
         client_.socket.receive(answer);
         client_.socket.getErrorText.writeln;
         return (cast(string) 
 answer).deserialize!config_create_answer;
     }

     unittest
     {
         import std.exception : collectException;

         auto cli = new 
 CLI("/tmp/raven-os_service_albinos.sock");
         assert(cli.create_config(["create_config", 
 "--name=toto"])
                 .state == "SUCCESS", "should be success");
         assert(cli.create_config(["create_config", 
 "--name=\"titi\""])
                 .state == "SUCCESS", "should be success");
         
 assert(collectException(cli.create_config(["create_config", 
 "--name="]))); //here is my problem
     }
 ```

 i would like to specify `collectException!GetOptException`, but 
 it's seem's make the program exit with fail status.

 any idea what i'm doing wrong ?

 also it's my first d program, so if anything seem's bad let me 
 know


I haven't spot the exact position of the problem yet, but I think 
the usage of assert is not correct at same places of your coding.

- Assertions are for logic errors, not for issues related to 
resources (network, files, input from users,...)
You cannot recover from a logic error, there assert terminates 
the application.

- for resource issues you should throw Exceptions. You can 
recover from resource issues.

- assertions throwing "Errors" which are not catched by 
collectException.

Kind regards
Andre
Mar 18 2019
prev sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 03/18/2019 11:54 AM, Roman Sztergbaum wrote:

 Hello as the subject say i'm asking this question because with the
 following code


Andre Pany has already explained. Otherwise, I was going to say 
"collectException can collect Exceptions, not exceptions." ;)

There have been many discussions on the General forum on when to call 
assert() vs. enforce() (essentially, 'throw new Exception') and what 
should go inside contracts.

Unrelated, with expression based contracts and the 'body' keyword now 
being an optional (context-dependent?) keyword, your function can be 
written more cleanly:

private config_create_answer create_config(string[] args)
    in (args !is null, "args cannot be null")
    in (args.length == 2, "need 1 arguments")
    out (r; r.state == "SUCCESS", "create_config should success")
    out (r; !r.config_key.empty, "config_key should not be empty")
    out (r; !r.readonly_config_key.empty, "readonly_config_key should 
not be empty");
{
   // ...
}

Ali
Mar 18 2019
parent reply Roman Sztergbaum <rmscastle gmail.com> writes:
On Tuesday, 19 March 2019 at 00:07:44 UTC, Ali Çehreli wrote:

 On 03/18/2019 11:54 AM, Roman Sztergbaum wrote:

 [...]


 with the

 [...]


 Andre Pany has already explained. Otherwise, I was going to say 
 "collectException can collect Exceptions, not exceptions." ;)

 [...]


Hello,

What happen if the contract is not respected in this case ? since 
you dont have any assert inside the contract ?

Thank's a lot !
Mar 19 2019
parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 03/19/2019 12:00 AM, Roman Sztergbaum wrote:

 On Tuesday, 19 March 2019 at 00:07:44 UTC, Ali Çehreli wrote:

 On 03/18/2019 11:54 AM, Roman Sztergbaum wrote:

 [...]


 with the

 [...]


 Andre Pany has already explained. Otherwise, I was going to say 
 "collectException can collect Exceptions, not exceptions." ;)

 [...]


 
 Hello,
 
 What happen if the contract is not respected in this case ? since you 
 dont have any assert inside the contract ?
 
 Thank's a lot !


You didn't quote that part but I think you're referring to the 
expression-based contracts. Actually, the asserts are still there but 
the syntax is cleaner. That syntax was introduced in 2.081.0:

   https://dlang.org/changelog/2.081.0.html#expression-based_contract_syntax

I have a section about them as well:

 
http://ddili.org/ders/d.en/contracts.html#ix_contracts.expression-based%20contracts

Ali
Mar 19 2019