[Overriding] panic when attempting to use Plugin overrides #296
Description
Describe the bug
Overriding code panics when attempting to merge plugin overrides, due to this line. When overrides do not contain e.g. projects, keySets has length 1.
Stacktrace:
{"level":"info","ts":1610388875.9142458,"logger":"controllers.DevWorkspace","msg":"Reconciling Workspace","Request.Namespace":"dw","Request.Name":"theia-nodejs","workspace_id":"workspacea86f74107bad4cb7"}
E0111 13:14:36.162339 83107 runtime.go:78] Observed a panic: runtime.boundsError{x:1, y:1, signed:true, code:0x0} (runtime error: index out of range [1] with length 1)
goroutine 675 [running]:
k8s.io/apimachinery/pkg/util/runtime.logPanic(0x1e925e0, 0xc0008ae320)
/home/amisevsk/go/pkg/mod/k8s.io/apimachinery@v0.18.8/pkg/util/runtime/runtime.go:74 +0x131
k8s.io/apimachinery/pkg/util/runtime.HandleCrash(0x0, 0x0, 0x0)
/home/amisevsk/go/pkg/mod/k8s.io/apimachinery@v0.18.8/pkg/util/runtime/runtime.go:48 +0xd8
panic(0x1e925e0, 0xc0008ae320)
/usr/lib/golang/src/runtime/panic.go:975 +0x41b
github.com/devfile/api/pkg/utils/overriding.ensureOnlyExistingElementsAreOverridden.func1(0x1f79d67, 0x8, 0xc0008f6090, 0x1, 0x1, 0x0, 0x0, 0x0)
/home/amisevsk/go/pkg/mod/github.com/devfile/api@v0.0.0-20201125082321-aeda60d43619/pkg/utils/overriding/overriding.go:119 +0x361
github.com/devfile/api/pkg/utils/overriding.checkKeys(0x2029df8, 0xc000c1a158, 0x2, 0x2, 0x0, 0x0)
/home/amisevsk/go/pkg/mod/github.com/devfile/api@v0.0.0-20201125082321-aeda60d43619/pkg/utils/overriding/keys.go:32 +0x53c
github.com/devfile/api/pkg/utils/overriding.ensureOnlyExistingElementsAreOverridden(0xc0009207a0, 0x2237e00, 0xc000ac68a0, 0x0, 0x0)
/home/amisevsk/go/pkg/mod/github.com/devfile/api@v0.0.0-20201125082321-aeda60d43619/pkg/utils/overriding/overriding.go:117 +0x12c
github.com/devfile/api/pkg/utils/overriding.OverrideDevWorkspaceTemplateSpec(0xc0009207a0, 0x2237e00, 0xc000ac68a0, 0x0, 0x0, 0x0)
/home/amisevsk/go/pkg/mod/github.com/devfile/api@v0.0.0-20201125082321-aeda60d43619/pkg/utils/overriding/overriding.go:59 +0x110