When I run a command without providing it value to STDIN in circleci, I expect there to be no input.
There are 2 null bytes in STDIN
If you read from STDIN in ruby without providing a stdin then an error should be raised:
$ ruby -e "STDIN.read_nonblock(10000)"
Traceback (most recent call last):
1: from -e:1:in `<main>'
<internal:io>:63:in `read_nonblock': Resource temporarily unavailable - read would block (IO::EAGAINWaitReadable)
This is because there's nothing in STDIN.
When you execute a raw read from STDIN on CircleCI you instead get this:
#!/bin/bash -eo pipefail
ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect"
"\x00\x00"
Note: There's two null characters here, there should be nothing or an IO::EAGAINWaitReadable error.
To get this output run:
$ circleci local execute
It looks like these bytes get passed to every run: command, if you add multiple run commands it happens every time:
version: 2.1
orbs:
heroku: circleci/[email protected]
jobs:
build:
docker:
- image: circleci/ruby:2.7
steps:
- run: 'ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0'
- run: 'ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0'
- run: 'ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0'
workflows:
version: 2.1
default-ci-workflow:
jobs:
- build
Generates:
The redacted variables listed above will be masked in run step output.====>> ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
#!/bin/bash -eo pipefail
ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
"\x00\x00"
====>> ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
#!/bin/bash -eo pipefail
ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
"\x00\x00"
====>> ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
#!/bin/bash -eo pipefail
ruby -e "require \"io/console\"; STDIN.raw!; puts STDIN.read_nonblock(1000).inspect" || exit 0
"\x00\x00"
Success!
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