问题
I git cloned a Node.js application (the version specified in the package.json being 4.1.2 and that of my local machine being 6.2.2) and tried to git push on Heroku. But it failed to build and gave this error:
Failed to detect set buildpack https://codon-buildpacks.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz
Now I set the buildpack to heroku/nodejs and I get this message:
Buildpack set. Next release on lit-badlands-92088 will use heroku/nodejs.
Run git push heroku master to create a new release using this buildpack.
Now when I run git push heroku master, I am again told:
remote: -----> Failed to detect set buildpack
https://codon-buildpacks.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz
remote: More info:
https://devcenter.heroku.com/articles/buildpacks#detection-failure
remote:
remote: ! Push failed
remote: Verifying deploy...
remote:
remote: ! Push rejected to lit-badlands-92088.
What could be the possible reasons for the Node.js buildpack not being detected even if I set it?
回答1:
This means that a package.json file isn't checked into the root of your git project, so Heroku is detecting that it isn't a Node.js app. You can see this locally:
git show master:package.json
To fix it, you'll want to be sure there is a package.json in the root of your project (where there is also a .git directory), and add it to git:
git add package.json
git commit -m 'track package.json'
The phrasing ('failed to detect set buildpack') could be improved. It should probably say 'failed to detect Node.js app'. When the buildpack's "detect" script is run (https://github.com/heroku/heroku-buildpack-nodejs/blob/master/bin/detect), it looks for a package.json file to verify that there's a node app available to build.
回答2:
It’s because Heroku thinks you are deploying a Node app. But what you are deploying is the public directory of a Node app, not Node code.
Heroku uses buildpacks to select how the ap is handled. You want to clear that Node association:
buildpacks:clear # clear all buildpacks set on the app
Which means that “Next release will detect buildpack normally.”, that should solve it for you.
ref: https://devcenter.heroku.com/articles/buildpacks
回答3:
I had similar issue, here are the steps which solved the problem.
heroku buildpacks:set heroku/nodejs
git push heroku master
Basically details are in the more info link -
This situation may also occur if you remove or rename a file that previously led to the automatic detection of your application type and thus the automatic setting of the detected buildpack on your application.
回答4:
If you are working on a branch, you need to set master to track your branch
git branch -f --track master origin/branch_name
Check for package.json in master
git show master:package.json
If it's available, trying pushing again.
git push heroku master
`
回答5:
Some tiny clarifications on other answers: The error "Failed to detect set buildpack https://codon-buildpacks.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz" or anything similar, means to say the GIT COMMIT you are trying to push to heroku was not DETECTED as a node.js app. (Note the capitals for subtleties).
I recently made a stupid mistake that made me aware of this: Running "ls -a" showed that my package.json and .git files were in the same root directory, as required by heroku. EXCEPT that the package.json file WAS NOT included in my latest git commit. Running "git status" alerted me that package.json was an untracked file. So I added it, and ta-da, pushing to heroku worked.
If you get an error related to buildpack, check that your GIT COMMIT has a package.json file in the root directory. If this is true, try manually specifying the buildpack with "heroku buildpacks:set heroku/nodejs" (or your desired language). This should resolve most errors related to buildpack detection.
回答6:
Most apps have at least one of these signatures present, so if you see this error, it usually means an important file isn't checked into your git repository:
Java: pom.xml
Ruby: Gemfile
Node.js: package.json
Python: requirements.txt / setup.py / Pipfile
PHP: composer.json / index.php
You should:
git add {file}
git commit -am 'added {file}
git push heroku master
来源：https://stackoverflow.com/questions/38658038/why-does-heroku-fail-to-detect-node-js-buildpack