SPFx problem with code from github

Question

I'm trying to use the CDB promoted links webpart (from github) for modern pages but I need to make changes to the code (just the colours, nothing structural), So far so good- runs on the workbench but I can't get it to turn into a working sppkg file. I get the following error:

C:\cdb-promoted-links\config\package-solution.json

Error: #/solution
   Additional properties not allowed: includeClientSideAssets
at C:\cdb-promoted-links\node_modules\@microsoft\node-core-library\lib\JsonSchema.js:185:19
at JsonSchema.validateObjectWithCallback (C:\cdb-promoted-links\node_modules\@microsoft\node-core-library\lib\JsonSchema.js:200:13)
at JsonSchema.validateObject (C:\cdb-promoted-links\node_modules\@microsoft\node-core-library\lib\JsonSchema.js:182:14)
at PackageSolutionTask.GulpTask._readConfigFile (C:\cdb-promoted-links\node_modules\@microsoft\gulp-core-build\lib\tasks\GulpTask.js:321:28)
at PackageSolutionTask.GulpTask.onRegister (C:\cdb-promoted-links\node_modules\@microsoft\gulp-core-build\lib\tasks\GulpTask.js:93:30)
at Object.initialize (C:\cdb-promoted-links\node_modules\@microsoft\gulp-core-build\lib\index.js:322:24)
at SPWebBuildRig.BuildRig.initialize (C:\cdb-promoted-links\node_modules\@microsoft\sp-build-common\lib\BuildRig.js:63:19)
at SPWebBuildRig.SPBuildRig.initialize (C:\cdb-promoted-links\node_modules\@microsoft\sp-build-common\lib\SPBuildRig.js:36:37)
at SPWebBuildRig.initialize (C:\cdb-promoted-links\node_modules\@microsoft\sp-build-web\lib\SPWebBuildRig.js:29:37)
at Object.exports.initialize (C:\cdb-promoted-links\node_modules\@microsoft\sp-build-web\lib\index.js:23:17)
at Object.<anonymous> (C:\cdb-promoted-links\gulpfile.js:6:7)
at Module._compile (module.js:577:32)
at Object.Module._extensions..js (module.js:586:10)
at Module.load (module.js:494:32)
at tryModuleLoad (module.js:453:12)
at Function.Module._load (module.js:445:3)
   [18:54:43] Error - Unknown
 JSON validation failed:
C:\cdb-promoted-links\config\package-solution.json

Error: #/solution
   Additional properties not allowed: includeClientSideAssets
[18:54:44] ==================[ Finished ]==================
Error - Unknown
JSON validation failed:

any tips?

edited to add: https://github.com/CloudDesignBox/cdb-promoted-links

through a process of trial and error I have managed to get a deployable web part.... thing is that it doesn't show up on any page when I go to add a webpart....

Answer 1

Sorry, this is a partial answer. For your now edited question, have you tried removing the "includeClientSideAssets" flag from the package-solution.json file? I experienced this earlier and it at least ran, I did not test the webpart was working as expected

Following on from that, I found this question via Google as I'm having the exact error you were getting before you edited your question on another webpart.

C:\cdb-promoted-links-master>gulp serve
Build target: DEBUG
C:\cdb-promoted-links-master\node_modules\@microsoft\node-core- 
library\lib\JsonSchema.js:178
    throw new Error(prefix + os.EOL +
    ^

Error: JSON validation failed:
C:\cdb-promoted-links-master\config\tslint.json

What did you do to fix it?

EDIT: There's a new version of SPFx, v1.6 that includes some breaking changes to how the tslint file works. Details here - https://github.com/SharePoint/sp-dev-docs/wiki/SharePoint-Framework-v1.6-release-notes