explain tar_option_set(error = “null”) in the debugging chapter

[wlandau]

Prework

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[wlandau]

Done in the debugging chapter rewrite.

[CorradoLanera]

@wlandau , in the chapter you have mentioned: "This is especially helpful with dynamic branching."

Why/how? If a branch of a pattern returns an error, i.e., a NULL returned output, does the branch's parent pattern succeed in merging its other branches so that the children(s) can run? Maybe, it could be of high utility to include the information in the manual. I have experienced an 8k branches pattern in the middle of a pipeline, with 1 single error; I would love to simply "ignore" before/instead of go backward to find the CSV row in the source file with the affecting line and change my "data-raw" (or create an additional middle target with that line removed). Maybe I could correct the issue in the future, but now I need a final result that simply ignores that.