printer, scanner: Don't produce unparsable output. #241
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The formatter will append a newline at the end of file, causing the output of printer.Format() to be invalid.
This (invalid) Unicode codepoint is used by the printer package to fix up the indentation of generated files. If this codepoint is present in the input, the package gets confused and removes more than it should, producing unparsable output.
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Thanks, this looks good. Note on point #2 that technically we probably should disallow any of the private use code points. I chose U+E123 because its slightly hinted at being human-made (1-2-3), but there are ~18,000 private use code points (HCL only uses one). Thanks! |
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This changes fix two cases in which
printer.Format()produced output that was not accepted byparser.Parse():\x00: the scanner accepted this, because nothing is following the null byte. The formatter, however, decides to add a newline at the end of the file, assuming that this would be a no-op. Upon re-parsing, the null byte is no longer the last character in the stream and produces an error.I think that it's sane to refuse those inputs as "invalid" and I think it's very unlikely that this will break existing use-cases.