prevent bash process substitution error in cygwin

[MatteoOreficeIT]

Signed-off-by: Matteo Orefice matteo.orefice@bites4bits.software

fixes /dev/fd/62 : No such file or directory running cli docker bash completion in cygwin

I founded cygwin bash cannot handle bash Process Substitution in __docker_fetch_info() function

- What I did

Added code to run in cygwin doesn't use Process Substitution and fallbacks to here string

- How I did it

read -r client_experimental server_experimental server_os < <(__docker_q version -f '{{.Client.Experimental}} {{.Server.Experimental}} {{.Server.Os}}')

could be rewritten as here string avoiding a pipe creation :

read -r client_experimental server_experimental server_os <<< "$(__docker_q version -f '{{.Client.Experimental}} {{.Server.Experimental}} {{.Server.Os}}')"

- How to verify it

1. Install cygwin
2. Copy ./contrib/completion/bash/docker onto /etc/bash_completion.d/docker
3. In bash prompt type docker and press multiple to trigger completion
4. Check errors have not been shown like /dev/fd/62 : No such file or directory

- Description for the changelog
Prevent bash docker/cli completion error /dev/fd/62 : No such file or directory from occurring under cygwin

[codecov-io]

Codecov Report

Merging #1650 into master will increase coverage by 0.1%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #1650     +/-   ##
=========================================
+ Coverage   56.07%   56.17%   +0.1%     
=========================================
  Files         306      300      -6     
  Lines       20950    20640    -310     
=========================================
- Hits        11747    11594    -153     
+ Misses       8354     8210    -144     
+ Partials      849      836     -13

[albers]

Thanks for reporting. I have to take a closer look and hope to get back on you on monday.

[albers]

I cannot reproduce the problem.
I know that cygwin used to have problems with process substitution, and I remember having seen this error message several times. But current versions seem to cope well with process substitiution:

$ cat < <(echo Hugo)
Hugo

I tested with current cygwin 32-bit on Windows 7 and current cygwin 64-bit on Windows 10.
Maybe your installation is outdated?

[albers]

As your improved version also works for other operating systems, there's no need to branch here by OS.
Please change line 596 to always use command substitution.

[thaJeztah]

@albers looks like the PR was updated

[albers]

I don't think we need this comment here. It will not be useful for readers once this PR is merged.
It is sufficient to mention the rationale behind this change in the commit message.

[albers]

LGTM, thanks very much for your contribution.

[thaJeztah]

LGTM, thanks!!

[MatteoOreficeIT]

Thanks to the docker community which allows us better devops, I hope to contribute many more time asap

[thaJeztah]

Thanks! That's really appreciated