odo build-images and odo deploy do not work with Docker if optional buildContext field is not set in Devfile

[rm3l]

/kind bug

What versions of software are you using?

Operating System:
Fedora 35

Output of odo version:
Using the main branch.
odo v2.5.0 (36f323d)

How did you run odo exactly?

Using this Devfile, inspired from https://github.com/kadel/devfile-nodejs-deploy/blob/main/devfile.yaml

❯ mkdir -p /tmp/aname
❯ cd /tmp/aname
❯ odo init --name aname --devfile-path https://gist.githubusercontent.com/rm3l/ee9a33d87d2e650f9ba688650c8659db/raw/26c37b4dabae724f0d1a29efab53aa5e3d66b764/devfile.yaml
❯ # To force using Docker in odo
❯ export PODMAN_CMD=a-command-not-found-should-make-odo-use-docker
❯ odo deploy -v 4
❯ odo build-images -v 4

Actual behavior

/tmp/aname on ☁️   
❯ odo init --name aname --devfile-path https://gist.githubusercontent.com/rm3l/ee9a33d87d2e650f9ba688650c8659db/raw/26c37b4dabae724f0d1a29efab53aa5e3d66b764/devfile.yaml
 ✓  Downloading devfile from "https://gist.githubusercontent.com/rm3l/ee9a33d87d2e650f9ba688650c8659db/raw/26c37b4dabae724f0d1a29efab53aa5e3d66b764/devfile.yaml" [156ms]                                                                      
                                                                                                                                                                                                                                               
Your new component "aname" is ready in the current directory.                                                                                                                                                                                  
To start editing your component, use "odo dev" and open this folder in your favorite IDE.                                                                                                                                                      
Changes will be directly reflected on the cluster.                                                                                                                                                                                             
To deploy your component to a cluster use "odo deploy". 

❯ # To force using Docker in odo
❯ export PODMAN_CMD=a-command-not-found-should-make-odo-use-docker
❯ odo deploy -v 4
I0329 14:21:58.925983  534901 implem.go:103] The path for preference file is /home/asoro/.odo/preference.yaml
I0329 14:21:58.926034  534901 util.go:733] HTTPGetRequest: https://raw.githubusercontent.com/redhat-developer/odo/main/build/VERSION
I0329 14:21:58.926072  534901 segment.go:254] Checking telemetry enable status
I0329 14:21:58.926083  534901 util.go:754] Response will be cached in /tmp/odohttpcache for 1h0m0s
I0329 14:21:58.926218  534901 util.go:767] Cached response used.
I0329 14:21:58.928310  534901 implem.go:103] The path for preference file is /home/asoro/.odo/preference.yaml
I0329 14:21:58.936098  534901 context.go:141] absolute devfile path: '/tmp/aname/devfile.yaml'
I0329 14:21:58.936109  534901 context.go:92] absolute devfile path: '/tmp/aname/devfile.yaml'
I0329 14:21:58.936440  534901 content.go:33] converted devfile YAML to JSON
I0329 14:21:58.936525  534901 apiVersion.go:45] devfile schemaVersion: '2.2.0'
I0329 14:21:58.936533  534901 helper.go:41] devfile apiVersion '2.2.0' is supported
I0329 14:21:58.938878  534901 schema.go:46] validated devfile schema
I0329 14:21:58.940118  534901 validate.go:45] Successfully validated devfile sections
I0329 14:21:58.940128  534901 validate.go:45] Successfully validated devfile sections
  __
 /  \__     Deploying the application using aname Devfile
 \__/  \    Namespace: default
 /  \__/    odo version: v2.5.0
 \__/

↪ Building & Pushing Container: localhost:5000/devfile-nodejs-deploy:latest
 •  Building image locally  ...
I0329 14:21:58.940309  534901 docker_compatible.go:66] Running command: docker build -t "localhost:5000/devfile-nodejs-deploy:latest" -f "/tmp/aname/Dockerfile" 
"docker build" requires exactly 1 argument.
See 'docker build --help'.

Usage:  docker build [OPTIONS] PATH | URL | -

Build an image from a Dockerfile
 ✗  Building image locally [24ms]
 ✗  error running docker command: exit status 1

❯ odo build-images -v 4
I0329 14:23:02.207365  536569 implem.go:103] The path for preference file is /home/asoro/.odo/preference.yaml
I0329 14:23:02.207434  536569 util.go:733] HTTPGetRequest: https://raw.githubusercontent.com/redhat-developer/odo/main/build/VERSION
I0329 14:23:02.207456  536569 segment.go:254] Checking telemetry enable status
I0329 14:23:02.207472  536569 util.go:754] Response will be cached in /tmp/odohttpcache for 1h0m0s
I0329 14:23:02.207564  536569 context.go:141] absolute devfile path: '/tmp/aname/devfile.yaml'
I0329 14:23:02.207576  536569 context.go:92] absolute devfile path: '/tmp/aname/devfile.yaml'
I0329 14:23:02.207600  536569 util.go:767] Cached response used.
I0329 14:23:02.207823  536569 content.go:33] converted devfile YAML to JSON
I0329 14:23:02.207875  536569 apiVersion.go:45] devfile schemaVersion: '2.2.0'
I0329 14:23:02.207880  536569 helper.go:41] devfile apiVersion '2.2.0' is supported
I0329 14:23:02.210673  536569 schema.go:46] validated devfile schema
I0329 14:23:02.211911  536569 validate.go:45] Successfully validated devfile sections
I0329 14:23:02.211921  536569 validate.go:45] Successfully validated devfile sections

↪ Building & Pushing Container: localhost:5000/devfile-nodejs-deploy:latest
 •  Building image locally  ...
I0329 14:23:02.212043  536569 docker_compatible.go:66] Running command: docker build -t "localhost:5000/devfile-nodejs-deploy:latest" -f "/tmp/aname/Dockerfile" 
"docker build" requires exactly 1 argument.
See 'docker build --help'.

Usage:  docker build [OPTIONS] PATH | URL | -

Build an image from a Dockerfile
 ✗  Building image locally [24ms]
 ✗  error running docker command: exit status 1

Expected behavior

The documentation states that:

The buildContext indicates the directory used as build context. The default value is ${PROJECT_SOURCE}.

If I understand correctly, buildContext should be an optional field defaulting to ${PROJECT_SOURCE}.
So I think we should support this default value if not set. Or, if required, exit with an appropriate error message.

I came across this issue when working on #5322, but I preferred to separate the issues / PRs.