Unable to yaml-merge trivial YAML

[wwkimball]

Hey there. I can't get 2 simple yaml files merged with this error thrown: ERROR: Impossible to add Scalar value, , to a Hash without a key. Change the value to a 'key: value' pair, a '{key: value}' Hash, or change the merge target to an Array or other Scalar value. This issue occurred at YAML Path: / I'm using a command: yaml-merge first.yaml second.yaml first.yaml replicaCount: 2 second.yaml replicaCount: 3 Basically at this point I've tried to merge lot's of different yamls and always get the same error. I've installed yamlPath with: pip3 install yamlpath Logs:

17-Jan-2021 17:02:16 | Downloading yamlpath-3.4.0.tar.gz (183 kB) 17-Jan-2021 17:02:17 | Collecting ruamel.yaml>=0.15.96 17-Jan-2021 17:02:17 | Downloading ruamel.yaml-0.16.12-py2.py3-none-any.whl (111 kB) 17-Jan-2021 17:02:17 | Building wheels for collected packages: yamlpath 17-Jan-2021 17:02:17 | Building wheel for yamlpath (setup.py): started 17-Jan-2021 17:02:18 | Building wheel for yamlpath (setup.py): finished with status 'done' 17-Jan-2021 17:02:18 | Created wheel for yamlpath: filename=yamlpath-3.4.0-py3-none-any.whl size=191879 sha256=bddb9fa117410c4ce366a7f59e4499037e45285fda782271c7ebcffe65dad516 17-Jan-2021 17:02:18 | Stored in directory: /tmp/.cache/pip/wheels/53/7d/0d/714e41a8161d84d39310352f4bc15ef1b2ceb8e14292edd3b4 17-Jan-2021 17:02:18 | Successfully built yamlpath 17-Jan-2021 17:02:18 | Installing collected packages: ruamel.yaml, yamlpath 17-Jan-2021 17:02:18 | Successfully installed ruamel.yaml-0.16.12 yamlpath-3.4.0 17-Jan-2021 17:02:19 | ERROR:  Impossible to add Scalar value, , to a Hash without a key.  Change the value to a 'key: value' pair, a '{key: value}' Hash, or change the merge target to an Array or other Scalar value.  This issue occurred at YAML Path:  /`

Do you know what could be the reason?

Originally posted by @Ndubovoi in https://github.com/wwkimball/yamlpath/discussions/108#discussioncomment-288984

[Ndubovoi]

I added -d to check detailed logs and noticed that at the end the tool is trying to process STDIN although I don't have - pseudofile specified Logs:

-- | -- 17-Jan-2021 17:40:44 | DEBUG:  yaml_merge::merge_multidoc:  Reporting status, 0. 17-Jan-2021 17:40:44 | Processing STDIN... 17-Jan-2021 17:40:44 | DEBUG:  Merger::_resolve_anchor_conflicts:  LHS Anchors: 17-Jan-2021 17:40:44 | DEBUG:  Merger::_resolve_anchor_conflicts:  RHS Anchors: 17-Jan-2021 17:40:44 | DEBUG:  Processor::_get_optional_nodes:  Finally returning data of type <class 'ruamel.yaml.comments.CommentedMap'>: 17-Jan-2021 17:40:44 | DEBUG:  Processor::_get_optional_nodes:  [replicaCount]3<class 'int'> 17-Jan-2021 17:40:44 | DEBUG:  Processor::get_nodes:  Relaying optional node: 17-Jan-2021 17:40:44 | DEBUG:  Processor::get_nodes:  (path) 17-Jan-2021 17:40:44 | DEBUG:  Processor::get_nodes:  (node)[replicaCount]3<class 'int'> 17-Jan-2021 17:40:44 | DEBUG:  Processor::get_nodes:  (parent)None 17-Jan-2021 17:40:44 | DEBUG:  Processor::get_nodes:  (parentref)None 17-Jan-2021 17:40:44 | Please try --help for more information. 17-Jan-2021 17:40:44 | DEBUG:  yaml_merge::merge_multidoc:  Reporting status, 6.

[wwkimball]

Please use the New Issue template to gather up all of the detail I need to replicate your issue. At present, I am unable to reproduce this. Here's what I see when I attempt the merge with your exact input files:

$ yaml-merge --version
yaml-merge 3.4.0

$ cat first.yaml 
replicaCount: 2

$ cat second.yaml 
replicaCount: 3

$ yaml-merge first.yaml second.yaml 
---
replicaCount: 3

$ echo $?
0

[wwkimball]

Also, specifying the - pseudofile is optional. When you open an input handle to yaml-merge, it will attempt to read from it unless explicitly instructed to ignore it. I'll assume you're running yaml-merge through some other program/context that has a STDIN handle open. In order to tell yaml-merge to ignore this (unintentional/unexpected) input, please use the --nostdin (-S) flag, per https://github.com/wwkimball/yamlpath/wiki/yaml-merge.

[Ndubovoi]

That was it. I was running it with docker.

Issue is resolved. Thank you.

[AndydeCleyre]

Ah! This is also relevant when running in a GitHub Actions Ubuntu environment.

I think the error message in this case could be more helpful.

[wwkimball]

Ah! This is also relevant when running in a GitHub Actions Ubuntu environment.

I think the error message in this case could be more helpful.

@AndydeCleyre I can take a look at the error messaging. I've added a task card for this to the upcoming 3.6.0 release: https://github.com/wwkimball/yamlpath/projects/3#card-61666733

[wwkimball]

Starting with yamlpath version 3.6.0, whenever this error condition is raised while the STDIN handle is open, the error above is expanded to become the following text:

ERROR: Impossible to add Scalar value, , to a Hash without a key. Change the value to a 'key: value' pair, a '{key: value}' Hash, or change the merge target to an Array or other Scalar value. You may be seeing this because your workflow inadvertently opened a STDIN handle to yaml-merge. If this may be the case, try adding --nostdin or -S so as to block unintentional STDIN reading. This issue occurred at YAML Path: / Please try --help for more information.

When STDIN is closed, the message continues to be the shorter, original version.

[wwkimball]

I have published version 3.6.0 which includes this change, and many more.