[Elm] Template improvements #661

laughedelic · 2018-07-26T22:05:31Z

PR checklist

Read the contribution guidelines.
Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
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Description of the PR

This PR fixes #458 and improves doc comments and line spacing in the Elm template. (see also swagger-api/swagger-codegen#8152 for the context).

There are still some extra newlines that are hard to get rid of. They appear because the {{>blah}} includes bring the last newline in the parent template. I don't know if this can be somehow improved on the Mustache side, but in general it's quite hard to produce some code that immediately complies with the formatting guideline (elm-format).

laughedelic · 2018-07-26T22:11:02Z

e4fa432 also solves swagger-api/swagger-codegen#8151

wing328 · 2018-07-27T10:11:48Z

They appear because the {{>blah}} includes bring the last newline in the parent template.

@laughedelic thanks for the PR 👍

Would removing the last newline in the parent (partial) template help? If you can point me to the line number in the template and show me the actual vs expected output, I can help take a look.

cc @trenneman

laughedelic · 2018-07-27T22:08:00Z

Would removing the last newline in the parent (partial) template help? If you can point me to the line number in the template and show me the actual vs expected output, I can help take a look.

As I understand it, the extra newline comes from the child template. So if you have an {{>child}} at the last line of the parent template, the result will have \n\n at the end, coming from the parent and the child.

Here is an example piece of template:

openapi-generator/modules/openapi-generator/src/main/resources/elm/modelTypeAlias.mustache

Lines 13 to 16 in e4fa432

    
           {{>aliasDecoder}} 
        
           {{>aliasEncoder}}

And the produced result:

openapi-generator/samples/client/petstore/elm/src/Data/ApiResponse.elm

Lines 30 to 47 in e4fa432

    
           apiResponseDecoder : Decoder ApiResponse 
        
           apiResponseDecoder = 
        
               decode ApiResponse 
        
                   |> optional "code" (Decode.nullable Decode.int) Nothing 
        
                   |> optional "type" (Decode.nullable Decode.string) Nothing 
        
                   |> optional "message" (Decode.nullable Decode.string) Nothing 
        
           apiResponseEncoder : ApiResponse -> Encode.Value 
        
           apiResponseEncoder model = 
        
               Encode.object 
        
                   [ ( "code", withDefault Encode.null (map Encode.int model.code) ) 
        
                   , ( "type", withDefault Encode.null (map Encode.string model.type_) ) 
        
                   , ( "message", withDefault Encode.null (map Encode.string model.message) ) 
        
                   ]

One extra newline is added after inlining the aliasDecoder, same with the aliasEncoder, and then one more in the end, because the modelTypeAlias is itself inlined in the model template.

Ah, and here is the expected output:

apiResponseDecoder : Decoder ApiResponse 
 apiResponseDecoder = 
     decode ApiResponse 
         |> optional "code" (Decode.nullable Decode.int) Nothing 
         |> optional "type" (Decode.nullable Decode.string) Nothing 
         |> optional "message" (Decode.nullable Decode.string) Nothing 
  
  
 apiResponseEncoder : ApiResponse -> Encode.Value 
 apiResponseEncoder model = 
     Encode.object 
         [ ( "code", withDefault Encode.null (map Encode.int model.code) ) 
         , ( "type", withDefault Encode.null (map Encode.string model.type_) ) 
         , ( "message", withDefault Encode.null (map Encode.string model.message) ) 
         ]

(no empty lines in the end and only 2 between the definitions)

wing328 · 2018-07-30T16:24:21Z

@laughedelic @trenneman I suggest we merge this and deal with the extra newline in a separate PR.

eriktim

I've been struggling a lot with newlines as well. It's a PITA with mustache.
A few remarks, but it looks OK other than that (and the remaining newline issue).

eriktim · 2018-07-31T11:02:57Z

bin/elm-petstore.sh

@@ -27,6 +27,6 @@ fi

 # if you've executed sbt assembly previously it will use that instead.
 export JAVA_OPTS="${JAVA_OPTS} -XX:MaxPermSize=256M -Xmx1024M -DloggerPath=conf/log4j.properties"
-ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g elm -o samples/client/petstore/elm $@"
+ags="generate -i modules/openapi-generator/src/test/resources/2_0/petstore.yaml -g elm -t modules/openapi-generator/src/main/resources/elm -o samples/client/petstore/elm $@"


do we need this?

Yes, I think so as using -t allows us to regenerate the samples without doing another "mvn clean package" after updating the templates.

Yes, I also checked that it's used in other scripts.

It feels a bit weird that it sort of overloads the build, but it makes sense to add it if that's also the case for the other generators.

eriktim · 2018-07-31T11:04:17Z

modules/openapi-generator/src/main/resources/elm/DateOnly.mustache

-                    ++ str
-                    ++ " to DateOnly"
+        Result.Err msg ->
+            Decode.fail msg


Something like Decode.fail <| "Cannot decode ISO string: " ++ msg makes clear that it's the decoder that failed

The error message in the new date-extra is

Failed to create a Date from string 'foo': Invalid ISO 8601 format

Do you still want to add "Cannot decode ISO string: "?

Well the thing is this is a Decoder error, not a Date error. But the type already indicates that so I think we can stick with the Decode.fail msg.

eriktim · 2018-07-31T11:04:46Z

modules/openapi-generator/src/main/resources/elm/DateTime.mustache

-                    ++ str
-                    ++ " to DateTime"
+        Result.Err msg ->
+            Decode.fail msg


The same here

laughedelic · 2018-08-04T23:33:23Z

Hi! I replied to the review comments and now I'm not sure if there's still anything left to change.

wing328 · 2018-08-05T09:37:34Z

If no more question/feedback on this PR, I'll merge it into master tomorrow (Monday)

andys8 · 2018-08-06T12:06:17Z

Nice!

wing328 · 2018-08-23T07:06:47Z

Hi all, I've filed #879 to improve the code format of the Elm client by removing the EOF from 2 mustache files. Please review to see if it looks good to you.

wing328 · 2018-08-26T08:40:37Z

#879 has been reviewed and merged into master.

Shall we use https://github.com/jfmengels/elm-lint to improve the auto-generated Elm code? (I've no experience using it)

eriktim · 2018-08-26T09:26:12Z

@wing328 You typically use elm-format for that. You want to add this as a post-processing step?

andys8 · 2018-08-26T09:55:55Z

elm-format does formatting and minor changes (like changing import order). elm-analyse is a longer (static code analysis). We could avoid the two dependencies by making sure the templates themselves are formatted correctly. But it could also be a benefit to make it sure by using elm-format.

wing328 · 2018-08-26T10:02:06Z

Thanks for the suggestion guys. I will see if I can come up with a solution to run elm-format for each auto-generated Elm files. Will keep you guys posted.

eriktim · 2018-08-26T10:29:56Z

That would help. However, my preference would be to format it correctly from the start, without any post-processing.

wing328 · 2018-08-30T08:47:12Z

That would help. However, my preference would be to format it correctly from the start, without any post-processing.

Totally agree but we found that it's not easy to do so with mustache.

For Go, we're trying to use gofmt -w and the result looks good so far: #929

I've created #933 to track the code format improvement

* Add elm template parameter to the samples testing script * Update elm-date-extra package; fixes OpenAPITools#458 * Update generated elm samples * Use Elm doc comments; remove some unneccessary newlines * Update generated Elm samples * Remove unnecessary parenthesis around non-optional container type

laughedelic added 6 commits July 26, 2018 17:01

Add elm template parameter to the samples testing script

15e5e57

Update elm-date-extra package; fixes OpenAPITools#458

d7e0aff

Update generated elm samples

1347b98

Use Elm doc comments; remove some unneccessary newlines

4f649e4

Update generated Elm samples

108e20a

Remove unnecessary parenthesis around non-optional container type

e4fa432

wing328 added Client: Elm Enhancement: General labels Jul 27, 2018

wing328 added this to the 3.2.0 milestone Jul 27, 2018

eriktim requested changes Jul 31, 2018

View reviewed changes

wing328 merged commit 05db32f into OpenAPITools:master Aug 6, 2018

laughedelic deleted the elm-improvs branch August 6, 2018 13:09

wing328 mentioned this pull request Aug 23, 2018

Remove EOF from Elm mustache template for better code format #879

Merged

4 tasks

andys8 mentioned this pull request Aug 26, 2018

[Elm] List in type alias has unnecessary parentheses swagger-api/swagger-codegen#8151

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[Elm] Template improvements #661

[Elm] Template improvements #661

laughedelic commented Jul 26, 2018

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[Elm] Template improvements #661

[Elm] Template improvements #661

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laughedelic commented Jul 26, 2018

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Description of the PR

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