BUG::PIPELINE::EXPRESSION BUILDER::EDITS NOT SAVED

I figured out what the issue was:

when rows are copied, this is what the JSON output from the Copy data activity looks like:

{
	"dataRead": 33,
	"dataWritten": 1685,
	"filesWritten": 1,
	"sourcePeakConnections": 1,
	"sinkPeakConnections": 1,
	"rowsRead": 1,
	"rowsCopied": 1,
	"copyDuration": 10,
	"throughput": 0.01,
	"errors": [],
	"usedParallelCopies": 1,
	"executionDetails": [
		{
			"source": {
				"type": "SqlServer"
			},
			"sink": {
				"type": "Lakehouse"
			},
			"status": "Succeeded",
			"start": "4/18/2024, 11:29:47 PM",
			"duration": 10,
			"usedParallelCopies": 1,
			"profile": {
				"queue": {
					"status": "Completed",
					"duration": 0
				},
				"transfer": {
					"status": "Completed",
					"duration": 6,
					"details": {
						"readingFromSource": {
							"type": "SqlServer",
							"workingDuration": 0,
							"timeToFirstByte": 0
						},
						"writingToSink": {
							"type": "Lakehouse",
							"workingDuration": 0
						}
					}
				}
			},
			"detailedDurations": {
				"queuingDuration": 0,
				"timeToFirstByte": 0,
				"transferDuration": 6
			}
		}
	],
	"dataConsistencyVerification": {
		"VerificationResult": "NotVerified"
	}
}

but when there is no new data to be copied, the rowsCopied is not there in the JSON even though it should be equal to 0 and still be in the JSON:

{
	"dataRead": 0,
	"dataWritten": 0,
	"filesWritten": 0,
	"sourcePeakConnections": 1,
	"sinkPeakConnections": 1,
	"rowsRead": 0,
	"copyDuration": 7,
	"throughput": 0,
	"errors": [],
	"usedParallelCopies": 1,
	"executionDetails": [
		{
			"source": {
				"type": "SqlServer"
			},
			"sink": {
				"type": "Lakehouse"
			},
			"status": "Succeeded",
			"start": "4/19/2024, 1:29:48 AM",
			"duration": 7,
			"usedParallelCopies": 1,
			"profile": {
				"queue": {
					"status": "Completed",
					"duration": 0
				},
				"transfer": {
					"status": "Completed",
					"duration": 4,
					"details": {
						"readingFromSource": {
							"type": "SqlServer",
							"workingDuration": 0,
							"timeToFirstByte": 2
						},
						"writingToSink": {
							"type": "Lakehouse",
							"workingDuration": 0
						}
					}
				}
			},
			"detailedDurations": {
				"queuingDuration": 0,
				"timeToFirstByte": 2,
				"transferDuration": 2
			}
		}
	],
	"dataConsistencyVerification": {
		"VerificationResult": "NotVerified"
	}
}

So in other words, when rowsRead == 0, rowsCopied property is removed from the output JSON instead of being left there with value 0. 

And this causes the flow to break, or rather forces the user to add some code like 'if rowsRead ==0 then... else rowsCopied...', which is less user friendly than just leave rowsCopied in the JSON.  For logging purpose, that is fine to just print rowsCopied == 0, it's the point after all.