Fix a few issues with the C generator (part 1 version 2) (#14434)

* C: add a template for an empty any_type.h header

Some generated C apis fail to build because the source files get
'#include "any_type.h"' lines, but no such header gets generated. As a
simple fix, add a new template for an empty file with that name. This is
enough to fix the problem for us, because all the generic type stuff is
handled by object_t.

* C: fix enums

I'm guessing that enums have not been used much with the C generator
before, because they always seem to produce code that doesn't build, or
that tries to free them after use. This patch fixes all the problems
we've encountered so far, except for those that need checking the return
type. I'll come back to that later.

* C: fix confusion of 'classname'/'classFilename'

* C: fix issues with returned enums

Currently, the C templates never check if a function returns an enum
inside mustache, so when that happens the generated code has broken
return types and doesn't build. I originally tried to fix this by
extending CodegenOperation to implement a 'returnTypeIsEnum' check, but
William Cheng suggested[1] that I use the existing 'returnProperty'
instead:

  https://github.com/OpenAPITools/openapi-generator/pull/14379#discussion_r1064636735

So do that.

* C: update the samples

As required for a pull request, run the generate-samples.sh script and
commit the changes.

* update samples

---------

Co-authored-by: William Cheng <wing328hk@gmail.com>

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java

@@ -368,6 +368,7 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
         // Object files in model folder
         supportingFiles.add(new SupportingFile("object-body.mustache", "model", "object.c"));
         supportingFiles.add(new SupportingFile("object-header.mustache", "model", "object.h"));
+        supportingFiles.add(new SupportingFile("any_type-header.mustache", "model", "any_type.h"));
     }
 
     @Override

modules/openapi-generator/src/main/resources/C-libcurl/CMakeLists.txt.mustache

@@ -76,6 +76,7 @@ set(HDRS
     include/keyValuePair.h
     external/cJSON.h
     model/object.h
+    model/any_type.h
 {{#models}}
 {{#model}}
     model/{{classFilename}}.h

modules/openapi-generator/src/main/resources/C-libcurl/any_type-header.mustache

@@ -0,0 +1,5 @@
+/*
+ * any_type.h
+ *
+ * A placeholder for now, this type isn't really needed.
+ */

modules/openapi-generator/src/main/resources/C-libcurl/api-body.mustache

@@ -98,7 +98,7 @@ end:
 // {{{.}}}
 //
 {{/notes}}
-{{#returnType}}{{#returnTypeIsPrimitive}}{{#returnSimpleType}}{{{.}}}*{{/returnSimpleType}}{{^returnSimpleType}}{{#isArray}}{{{.}}}_t*{{/isArray}}{{#isMap}}{{{.}}}{{/isMap}}{{/returnSimpleType}}{{/returnTypeIsPrimitive}}{{^returnTypeIsPrimitive}}{{{.}}}_t*{{/returnTypeIsPrimitive}}{{/returnType}}{{^returnType}}void{{/returnType}}
+{{#returnType}}{{#returnTypeIsPrimitive}}{{#returnSimpleType}}{{{.}}}*{{/returnSimpleType}}{{^returnSimpleType}}{{#isArray}}{{{.}}}_t*{{/isArray}}{{#isMap}}{{{.}}}{{/isMap}}{{/returnSimpleType}}{{/returnTypeIsPrimitive}}{{^returnTypeIsPrimitive}}{{#returnProperty}}{{^isEnum}}{{{returnType}}}_t*{{/isEnum}}{{#isEnum}}{{projectName}}_{{{returnType}}}_{{returnEnumName}}_e{{/isEnum}}{{/returnProperty}}{{/returnTypeIsPrimitive}}{{/returnType}}{{^returnType}}void{{/returnType}}
 {{{classname}}}_{{{operationId}}}(apiClient_t *apiClient{{#allParams}}, {{#isPrimitiveType}}{{#isNumber}}{{{dataType}}} {{/isNumber}}{{#isLong}}{{{dataType}}} {{/isLong}}{{#isInteger}}{{{dataType}}} *{{/isInteger}}{{#isDouble}}{{{dataType}}} {{/isDouble}}{{#isFloat}}{{{dataType}}} {{/isFloat}}{{#isBoolean}}{{dataType}} *{{/isBoolean}}{{#isEnum}}{{#isString}}{{projectName}}_{{operationId}}_{{baseName}}_e {{/isString}}{{/isEnum}}{{^isEnum}}{{#isString}}{{{dataType}}} *{{/isString}}{{/isEnum}}{{#isByteArray}}{{{dataType}}} *{{/isByteArray}}{{#isDate}}{{{dataType}}} {{/isDate}}{{#isDateTime}}{{{dataType}}} {{/isDateTime}}{{#isFile}}{{{dataType}}} {{/isFile}}{{#isFreeFormObject}}{{dataType}}_t *{{/isFreeFormObject}}{{/isPrimitiveType}}{{^isArray}}{{^isPrimitiveType}}{{#isModel}}{{#isEnum}}{{datatypeWithEnum}}_e {{/isEnum}}{{^isEnum}}{{{dataType}}}_t *{{/isEnum}}{{/isModel}}{{^isModel}}{{#isEnum}}{{datatypeWithEnum}}_e {{/isEnum}}{{/isModel}}{{#isUuid}}{{dataType}} *{{/isUuid}}{{#isEmail}}{{dataType}} {{/isEmail}}{{/isPrimitiveType}}{{/isArray}}{{#isContainer}}{{#isArray}}{{dataType}}_t *{{/isArray}}{{#isMap}}{{dataType}} {{/isMap}}{{/isContainer}}{{{paramName}}}{{/allParams}})
 {
     list_t    *localVarQueryParameters = {{#hasQueryParams}}list_createList();{{/hasQueryParams}}{{^hasQueryParams}}NULL;{{/hasQueryParams}}
@@ -263,7 +263,7 @@ end:
     {{#isPrimitiveType}}{{#isNumber}}{{{dataType}}}{{/isNumber}}{{#isLong}}{{{dataType}}}{{/isLong}}{{#isInteger}}{{{dataType}}}{{/isInteger}}{{#isDouble}}{{{dataType}}}{{/isDouble}}{{#isFloat}}{{{dataType}}}{{/isFloat}}{{#isBoolean}}{{dataType}}{{/isBoolean}}{{#isEnum}}{{#isString}}{{projectName}}_{{operationId}}_{{baseName}}_e{{/isString}}{{/isEnum}}{{^isEnum}}{{#isString}}{{{dataType}}} *{{/isString}}{{/isEnum}}{{#isByteArray}}{{{dataType}}} *{{/isByteArray}}{{#isDate}}{{{dataType}}}{{/isDate}}{{#isDateTime}}{{{dataType}}}{{/isDateTime}}{{#isFile}}{{{dataType}}}{{/isFile}}{{/isPrimitiveType}}{{^isPrimitiveType}}{{#isModel}}{{#isEnum}}{{datatypeWithEnum}}_e{{/isEnum}}{{^isEnum}}{{{dataType}}}_t *{{/isEnum}}{{/isModel}}{{^isModel}}{{#isEnum}}{{datatypeWithEnum}}_e{{/isEnum}}{{/isModel}}{{#isUuid}}{{dataType}} *{{/isUuid}}{{#isEmail}}{{dataType}}{{/isEmail}}{{/isPrimitiveType}} valueForm_{{paramName}} = 0;
     keyValuePair_t *keyPairForm_{{paramName}} = 0;
     {{/isFile}}
-    if ({{paramName}} != NULL)
+    if ({{paramName}} != {{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}})
     {
         {{#isFile}}
         keyForm_{{paramName}} = strdup("{{{baseName}}}");
@@ -399,9 +399,9 @@ end:
     {{^returnContainer}}
     //nonprimitive not container
     cJSON *{{classname}}localVarJSON = cJSON_Parse(apiClient->dataReceived);
-    {{{returnBaseType}}}_t *elementToReturn = {{{returnBaseType}}}_parseFromJSON({{classname}}localVarJSON);
+    {{#returnProperty}}{{^isEnum}}{{{returnBaseType}}}_t *{{/isEnum}}{{#isEnum}}{{projectName}}_{{{returnType}}}_{{returnEnumName}}_e {{/isEnum}}{{/returnProperty}}elementToReturn = {{{returnBaseType}}}_parseFromJSON({{classname}}localVarJSON);
     cJSON_Delete({{classname}}localVarJSON);
-    if(elementToReturn == NULL) {
+    if(elementToReturn == {{#returnProperty}}{{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}}{{/returnProperty}}) {
         // return 0;
     }
 
@@ -524,8 +524,10 @@ end:
         keyForm_{{{paramName}}} = NULL;
     }
     if (valueForm_{{{paramName}}}) {
+        {{^isEnum}}
         free(valueForm_{{{paramName}}});
-        valueForm_{{{paramName}}} = NULL;
+        {{/isEnum}}
+        valueForm_{{{paramName}}} = {{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}};
     }
     free(keyPairForm_{{paramName}});
     {{/isString}}
@@ -541,7 +543,7 @@ end:
     return elementToReturn;
 end:
     free(localVarPath);
-    return NULL;
+    return {{#returnProperty}}{{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}}{{/returnProperty}};
     {{/returnType}}
     {{^returnType}}
     //No return type

modules/openapi-generator/src/main/resources/C-libcurl/api-header.mustache

@@ -32,7 +32,7 @@ typedef enum  { {{projectName}}_{{operationId}}_{{enumName}}_NULL = 0{{#enumVars
 // {{{.}}}
 //
 {{/notes}}
-{{#returnType}}{{#returnTypeIsPrimitive}}{{#returnSimpleType}}{{{.}}}*{{/returnSimpleType}}{{^returnSimpleType}}{{#isArray}}{{{.}}}_t*{{/isArray}}{{#isMap}}{{{.}}}{{/isMap}}{{/returnSimpleType}}{{/returnTypeIsPrimitive}}{{^returnTypeIsPrimitive}}{{{.}}}_t*{{/returnTypeIsPrimitive}}{{/returnType}}{{^returnType}}void{{/returnType}}
+{{#returnType}}{{#returnTypeIsPrimitive}}{{#returnSimpleType}}{{{.}}}*{{/returnSimpleType}}{{^returnSimpleType}}{{#isArray}}{{{.}}}_t*{{/isArray}}{{#isMap}}{{{.}}}{{/isMap}}{{/returnSimpleType}}{{/returnTypeIsPrimitive}}{{^returnTypeIsPrimitive}}{{#returnProperty}}{{^isEnum}}{{{returnType}}}_t*{{/isEnum}}{{#isEnum}}{{projectName}}_{{{returnType}}}_{{returnEnumName}}_e{{/isEnum}}{{/returnProperty}}{{/returnTypeIsPrimitive}}{{/returnType}}{{^returnType}}void{{/returnType}}
 {{{classname}}}_{{{operationId}}}(apiClient_t *apiClient{{#allParams}}, {{#isPrimitiveType}}{{#isNumber}}{{{dataType}}} {{/isNumber}}{{#isLong}}{{{dataType}}} {{/isLong}}{{#isInteger}}{{{dataType}}} *{{/isInteger}}{{#isDouble}}{{{dataType}}} {{/isDouble}}{{#isFloat}}{{{dataType}}} {{/isFloat}}{{#isBoolean}}{{dataType}} *{{/isBoolean}}{{#isEnum}}{{#isString}}{{projectName}}_{{operationId}}_{{baseName}}_e {{/isString}}{{/isEnum}}{{^isEnum}}{{#isString}}{{{dataType}}} *{{/isString}}{{/isEnum}}{{#isByteArray}}{{{dataType}}} *{{/isByteArray}}{{#isDate}}{{{dataType}}} {{/isDate}}{{#isDateTime}}{{{dataType}}} {{/isDateTime}}{{#isFile}}{{{dataType}}} {{/isFile}}{{#isFreeFormObject}}{{dataType}}_t *{{/isFreeFormObject}}{{/isPrimitiveType}}{{^isArray}}{{^isPrimitiveType}}{{#isModel}}{{#isEnum}}{{datatypeWithEnum}}_e {{/isEnum}}{{^isEnum}}{{{dataType}}}_t *{{/isEnum}}{{/isModel}}{{^isModel}}{{#isEnum}}{{datatypeWithEnum}}_e {{/isEnum}}{{/isModel}}{{#isUuid}}{{dataType}} *{{/isUuid}}{{#isEmail}}{{dataType}} {{/isEmail}}{{/isPrimitiveType}}{{/isArray}}{{#isContainer}}{{#isArray}}{{dataType}}_t *{{/isArray}}{{#isMap}}{{dataType}} {{/isMap}}{{/isContainer}}{{{paramName}}}{{/allParams}});
 
 

modules/openapi-generator/src/main/resources/C-libcurl/model-body.mustache

@@ -25,7 +25,7 @@ char* {{classFilename}}_{{classname}}_ToString({{projectName}}_{{classVarName}}_
     return 0;
 }
 
-cJSON *{{classFilename}}_{{classname}}_convertToJSON({{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}}) {
+cJSON *{{classname}}_convertToJSON({{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}}) {
     cJSON *item = cJSON_CreateObject();
 {{#isString}}
     if(cJSON_AddStringToObject(item, "{{{classname}}}", {{classFilename}}_{{{classname}}}_ToString({{{classname}}})) == NULL) {
@@ -48,7 +48,7 @@ fail:
     return NULL;
 }
 
-{{projectName}}_{{classVarName}}_{{enumName}}_e {{classFilename}}_{{classname}}_parseFromJSON(cJSON *{{classname}}JSON) {
+{{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}}_parseFromJSON(cJSON *{{classname}}JSON) {
     {{projectName}}_{{classVarName}}_{{enumName}}_e *{{classname}} = NULL;
 {{#isEnum}}
 {{#isNumeric}}
@@ -75,6 +75,7 @@ end:
 {{^isEnum}}
     {{#vars}}
     {{^isContainer}}
+    {{#isPrimitiveType}}
     {{^isModel}}
     {{#isEnum}}
 char* {{classname}}_{{name}}_ToString({{projectName}}_{{classVarName}}_{{enumName}}_e {{name}}) {
@@ -96,6 +97,7 @@ char* {{classname}}_{{name}}_ToString({{projectName}}_{{classVarName}}_{{enumNam
 }
     {{/isEnum}}
     {{/isModel}}
+    {{/isPrimitiveType}}
     {{/isContainer}}
     {{#isContainer}}
     {{#items}}
@@ -138,7 +140,12 @@ char* {{classname}}_{{name}}_ToString({{projectName}}_{{classVarName}}_{{enumNam
     {{/isModel}}
     {{^isModel}}
     {{^isFreeFormObject}}
+    {{^isEnum}}
     {{datatype}}_t *{{name}}{{^-last}},{{/-last}}
+    {{/isEnum}}
+    {{#isEnum}}
+    {{projectName}}_{{dataType}}_{{enumName}}_e {{name}}{{^-last}},{{/-last}}
+    {{/isEnum}}
     {{/isFreeFormObject}}
     {{/isModel}}
     {{#isUuid}}
@@ -227,10 +234,12 @@ void {{classname}}_free({{classname}}_t *{{classname}}) {
     {{/isModel}}
     {{^isModel}}
     {{^isFreeFormObject}}
+    {{^isEnum}}
     if ({{{classname}}}->{{{name}}}) {
         {{{complexType}}}_free({{{classname}}}->{{{name}}});
         {{classname}}->{{name}} = NULL;
     }
+    {{/isEnum}}
     {{/isFreeFormObject}}
     {{/isModel}}
     {{#isUuid}}
@@ -337,7 +346,12 @@ cJSON *{{classname}}_convertToJSON({{classname}}_t *{{classname}}) {
     }
     {{/isEnum}}
     {{#isEnum}}
+    {{#isPrimitiveType}}
     if ({{projectName}}_{{classVarName}}_{{enumName}}_NULL == {{{classname}}}->{{{name}}}) {
+    {{/isPrimitiveType}}
+    {{^isPrimitiveType}}
+    if ({{projectName}}_{{dataType}}_{{enumName}}_NULL == {{{classname}}}->{{{name}}}) {
+    {{/isPrimitiveType}}
         goto fail;
     }
     {{/isEnum}}
@@ -347,7 +361,12 @@ cJSON *{{classname}}_convertToJSON({{classname}}_t *{{classname}}) {
     if({{{classname}}}->{{{name}}}) {
     {{/isEnum}}
     {{#isEnum}}
+    {{#isPrimitiveType}}
     if({{{classname}}}->{{{name}}} != {{projectName}}_{{classVarName}}_{{enumName}}_NULL) {
+    {{/isPrimitiveType}}
+    {{^isPrimitiveType}}
+    if({{{classname}}}->{{{name}}} != {{projectName}}_{{dataType}}_{{enumName}}_NULL) {
+    {{/isPrimitiveType}}
     {{/isEnum}}
     {{/required}}
     {{^isContainer}}
@@ -589,7 +608,12 @@ fail:
     {{^isModel}}
     {{^isFreeFormObject}}
     // define the local variable for {{{classname}}}->{{{name}}}
+    {{^isEnum}}
     {{complexType}}_t *{{name}}_local_nonprim = NULL;
+    {{/isEnum}}
+    {{#isEnum}}
+    {{projectName}}_{{dataType}}_{{enumName}}_e {{name}}_local_nonprim = 0;
+    {{/isEnum}}
 
     {{/isFreeFormObject}}
     {{/isModel}}
@@ -853,7 +877,7 @@ fail:
         {{/isModel}}
         {{^isModel}}
         {{^isFreeFormObject}}
-        {{^required}}{{{name}}} ? {{/required}}{{{name}}}_local_nonprim{{^required}} : NULL{{/required}}{{^-last}},{{/-last}}
+        {{^required}}{{{name}}} ? {{/required}}{{{name}}}_local_nonprim{{^required}} : {{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}}{{/required}}{{^-last}},{{/-last}}
         {{/isFreeFormObject}}
         {{/isModel}}
         {{#isUuid}}
@@ -929,8 +953,10 @@ end:
     {{^isModel}}
     {{^isFreeFormObject}}
     if ({{{name}}}_local_nonprim) {
+        {{^isEnum}}
         {{complexType}}_free({{{name}}}_local_nonprim);
-        {{{name}}}_local_nonprim = NULL;
+        {{/isEnum}}
+        {{{name}}}_local_nonprim = {{^isEnum}}NULL{{/isEnum}}{{#isEnum}}0{{/isEnum}};
     }
     {{/isFreeFormObject}}
     {{/isModel}}

modules/openapi-generator/src/main/resources/C-libcurl/model-header.mustache

@@ -30,14 +30,15 @@ char* {{classFilename}}_{{classname}}_ToString({{projectName}}_{{classVarName}}_
 
 {{projectName}}_{{classVarName}}_{{enumName}}_e {{classFilename}}_{{classname}}_FromString(char* {{classname}});
 
-//cJSON *{{classFilename}}_{{classname}}_convertToJSON({{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}});
+cJSON *{{classname}}_convertToJSON({{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}});
 
-//{{projectName}}_{{classVarName}}_{{enumName}}_e {{classFilename}}_{{classname}}_parseFromJSON(cJSON *{{classname}}JSON);
+{{projectName}}_{{classVarName}}_{{enumName}}_e {{classname}}_parseFromJSON(cJSON *{{classname}}JSON);
 
 {{/isEnum}}
 {{^isEnum}}
 {{#vars}}
 {{^isContainer}}
+    {{#isPrimitiveType}}
     {{^isModel}}
     {{#isEnum}}
 // Enum {{enumName}} for {{classVarName}}
@@ -52,6 +53,7 @@ char* {{classFilename}}_{{name}}_ToString({{projectName}}_{{classVarName}}_{{enu
 
     {{/isEnum}}
     {{/isModel}}
+    {{/isPrimitiveType}}
     {{/isContainer}}
     {{#isContainer}}
     {{#items}}
@@ -88,7 +90,12 @@ typedef struct {{classname}}_t {
     {{/isModel}}
     {{^isModel}}
     {{^isFreeFormObject}}
+    {{^isEnum}}
     {{datatype}}_t *{{name}}; // custom
+    {{/isEnum}}
+    {{#isEnum}}
+    {{projectName}}_{{dataType}}_{{enumName}}_e {{name}}; //referenced enum
+    {{/isEnum}}
     {{/isFreeFormObject}}
     {{/isModel}}
     {{#isUuid}}
@@ -163,7 +170,12 @@ typedef struct {{classname}}_t {
     {{/isModel}}
     {{^isModel}}
     {{^isFreeFormObject}}
+    {{^isEnum}}
     {{datatype}}_t *{{name}}{{^-last}},{{/-last}}
+    {{/isEnum}}
+    {{#isEnum}}
+    {{projectName}}_{{dataType}}_{{enumName}}_e {{name}}{{^-last}},{{/-last}}
+    {{/isEnum}}
     {{/isFreeFormObject}}
     {{/isModel}}
     {{#isUuid}}

samples/client/petstore/c-useJsonUnformatted/.openapi-generator/FILES

@@ -26,6 +26,7 @@ include/binary.h
 include/keyValuePair.h
 include/list.h
 libcurl.licence
+model/any_type.h
 model/api_response.c
 model/api_response.h
 model/category.c

samples/client/petstore/c-useJsonUnformatted/CMakeLists.txt

@@ -75,6 +75,7 @@ set(HDRS
     include/keyValuePair.h
     external/cJSON.h
     model/object.h
+    model/any_type.h
     model/mapped_model.h
     model/api_response.h
     model/category.h

samples/client/petstore/c-useJsonUnformatted/model/any_type.h

@@ -0,0 +1,5 @@
+/*
+ * any_type.h
+ *
+ * A placeholder for now, this type isn't really needed.
+ */

samples/client/petstore/c/.openapi-generator/FILES

@@ -25,6 +25,7 @@ include/binary.h
 include/keyValuePair.h
 include/list.h
 libcurl.licence
+model/any_type.h
 model/api_response.c
 model/api_response.h
 model/category.c

samples/client/petstore/c/model/any_type.h

@@ -0,0 +1,5 @@
+/*
+ * any_type.h
+ *
+ * A placeholder for now, this type isn't really needed.
+ */