[neon-ninja]

Problem

encode() passed NaN coordinates through an undefined double -> int cast in encode_polyline() (src/googlePolylines.cpp). On x86 the cast yields INT_MIN, so a NaN pair emitted invalid polyline characters (bytes outside the valid 63–126 range, e.g. 0f ce 76 d7) and — because the format is delta-based — corrupted every subsequent point too. decode() on such a string threw a raw C++ exception (basic_string::at: __n >= this->size()). R's NA_real_ is a NaN at the C level, so NA triggered the same behaviour. Relatedly, empty sf POINTs (whose coordinates are NaN) encoded as "??", which silently decodes to the real coordinate (0, 0).

Changes

• encode_polyline() now skips coordinate pairs where lon or lat is not finite (NA/NaN/Inf); every entry point (encode(), encodeCoordinates(), the sf/sfc path) warns with a count of pairs that could not be encoded.
• encode(byrow = TRUE) returns NA for such rows instead of skipping (and decode() already maps NA strings back to NA coordinates).
• Empty sf POINTs now encode to "" (with the warning) instead of "??"/(0, 0); the test pinning the old behaviour was updated.
• RcppExports regenerated with Rcpp::compileAttributes(); roxygen docs updated (including the previously undocumented precision argument of decode()) and man pages regenerated.
• New testthat coverage for NA/NaN/Inf inputs, byrow, and empty points; NEWS entry; version bumped to 0.8.8.9000.

Testing

Full testthat suite (with NOT_CRAN=true): 161 pass, 0 fail. R CMD check (no vignettes/manual) shows nothing beyond pre-existing environment notes.

🤖 Generated with Claude Code

https://claude.ai/code/session_01UYymBnTDZbXyuus9FY97pd

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Generated by Claude Code

[dcooley]

My own notes:

From the tests:

df_nan
     lat      lon
1 38.500 -120.200
2    NaN      NaN
3 43.252 -126.453

Before this update this would round-trip as

decode(encode(df_nan))
[[1]]
     lat      lon
1 38.500 -120.200
2  0.000    0.000
3 43.252 -126.453

After this update this round-trips as

Warning message:
In rcpp_encode_polyline(obj[[lon]], obj[[lat]]) :
  1 coordinate pair(s) with missing or non-finite (NA/NaN/Inf) values could not be encoded

decode(encode(df_nan))
[[1]]
     lat      lon
1 38.500 -120.200
3 43.252 -126.453

The arugment being that a 'missing' row with a warning is better than a forced row of (0, 0) coordinates

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Similarly:

df_na
     lat     lon
1     NA -120.20
2 40.700 -120.95
3 43.252     Inf

now round-trips to

Warning message:
In rcpp_encode_polyline(obj[[lon]], obj[[lat]]) :
  2 coordinate pair(s) with missing or non-finite (NA/NaN/Inf) values could not be encoded

[[1]]
   lat     lon
1 40.7 -120.95