"a = 1" parsing gives invalid xml text (R 3.6.1)

[russHyde]

Hi. There's an issue running some xmlparsedata-dependent code within the tests for lintr on R-3.6.1 (r-lib/lintr#384) and I think it relates to xmlparsedata.

If I clone the current master (99a30b1) for xmlparsedata and run in an R-3.6.1 environment:

# from xmlparsedata directory
devtools::load_all()
devtools::test() # no errors are thrown for the existing tests

xml2::read_xml(xml_parse_data(parse(text = "a = 1", keep.source = TRUE)))
Error in doc_parse_raw(x, encoding = encoding, base_url = base_url, as_html = as_html,  : 
  Opening and ending tag mismatch: expr line 8 and equal_assign [76]

cat(xml_parse_data(parse(text = "a = 1", keep.source = TRUE), pretty = TRUE), file = "")

<?xml version="1.0" encoding="UTF-8"standalone="yes" ?>
<exprlist>
  <equal_assign line1="1" col1="1" line2="1" col2="5" start="7" end="11">
    <expr line1="1" col1="1" line2="1" col2="1" start="7" end="7">
      <SYMBOL line1="1" col1="1" line2="1" col2="1" start="7" end="7">a</SYMBOL>
    </expr>
    <EQ_ASSIGN line1="1" col1="3" line2="1" col2="3" start="9" end="9">=</EQ_ASSIGN>
    <expr line1="1" col1="5" line2="1" col2="5" start="11" end="11">
      <NUM_CONST line1="1" col1="5" line2="1" col2="5" start="11" end="11">1</NUM_CONST>
    </equal_assign>
  </expr>
</exprlist>

The xml that is produced isn't legal: equal_assign is interleaved with one of the exprs.

I with <- as the assignment operator, the xml is fine:

cat(xml_parse_data(parse(text = "a <- 1", keep.source = TRUE), pretty = TRUE), file = "")

<?xml version="1.0" encoding="UTF-8"standalone="yes" ?>
<exprlist>
  <expr line1="1" col1="1" line2="1" col2="6" start="8" end="13">
    <expr line1="1" col1="1" line2="1" col2="1" start="8" end="8">
      <SYMBOL line1="1" col1="1" line2="1" col2="1" start="8" end="8">a</SYMBOL>
    </expr>
    <LEFT_ASSIGN line1="1" col1="3" line2="1" col2="4" start="10" end="11">&lt;-</LEFT_ASSIGN>
    <expr line1="1" col1="6" line2="1" col2="6" start="13" end="13">
      <NUM_CONST line1="1" col1="6" line2="1" col2="6" start="13" end="13">1</NUM_CONST>
    </expr>
  </expr>
</exprlist>

> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-conda_cos6-linux-gnu (64-bit)
Running under: Ubuntu 18.04.2 LTS

Matrix products: default
BLAS/LAPACK: /home/ah327h/tools/miniconda3/envs/pkgs_lintr_361/lib/libopenblasp-r0.3.6.so

locale:
 [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_GB.UTF-8        LC_COLLATE=en_GB.UTF-8
 [5] LC_MONETARY=en_GB.UTF-8    LC_MESSAGES=en_GB.UTF-8
 [7] LC_PAPER=en_GB.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] xmlparsedata_1.0.2.9000 testthat_2.2.1

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.2        rstudioapi_0.10   xml2_1.2.2        magrittr_1.5
 [5] usethis_1.5.1     devtools_2.1.0    pkgload_1.0.2     R6_2.4.0
 [9] rlang_0.4.0       tools_3.6.1       pkgbuild_1.0.4    sessioninfo_1.1.1
[13] cli_1.1.0         withr_2.1.2       remotes_2.1.0     assertthat_0.2.1
[17] digest_0.6.20     rprojroot_1.3-2   crayon_1.3.4      processx_3.4.1
[21] callr_3.3.1       fs_1.3.1          ps_1.3.0          praise_1.0.0
[25] memoise_1.1.0     glue_1.3.1        compiler_3.6.1    desc_1.2.0
[29] backports_1.1.4   prettyunits_1.0.2

[russHyde]

However, if I run the same code in a R 3.5.1 environment:

devtools::load_all()
Loading xmlparsedata
> 
> devtools::test()
Loading xmlparsedata
Testing xmlparsedata
✔ |  OK F W S | Context
✔ |  17       | xmlparsedata [0.2 s]

══ Results ═════════════════════════════════════════════════════════════════════
Duration: 0.2 s

OK:       17
Failed:   0
Warnings: 0
Skipped:  0

Woot!
> 
# legal xml can be constructed:
> xml2::read_xml(xml_parse_data(parse(text = "a = 1", keep.source = TRUE)))
{xml_document}
<exprlist>
[1] <expr line1="1" col1="1" line2="1" col2="1" start="7" end="7">\n  <SYMBOL ...
[2] <EQ_ASSIGN line1="1" col1="3" line2="1" col2="3" start="9" end="9">=</EQ_ ...
[3] <expr line1="1" col1="5" line2="1" col2="5" start="11" end="11">\n  <NUM_ ...

# and the xml looks fine
> cat(xml_parse_data(parse(text = "a = 1", keep.source = TRUE), pretty = TRUE), file = "")

<?xml version="1.0" encoding="UTF-8"standalone="yes" ?>
<exprlist>
  <expr line1="1" col1="1" line2="1" col2="1" start="7" end="7">
    <SYMBOL line1="1" col1="1" line2="1" col2="1" start="7" end="7">a</SYMBOL>
  </expr>
  <EQ_ASSIGN line1="1" col1="3" line2="1" col2="3" start="9" end="9">=</EQ_ASSIGN>
  <expr line1="1" col1="5" line2="1" col2="5" start="11" end="11">
    <NUM_CONST line1="1" col1="5" line2="1" col2="5" start="11" end="11">1</NUM_CONST>
  </expr>
</exprlist>

sessionInfo()
R version 3.5.1 (2018-07-02)
Platform: x86_64-conda_cos6-linux-gnu (64-bit)
Running under: Ubuntu 18.04.2 LTS

Matrix products: default
BLAS/LAPACK: /home/ah327h/tools/miniconda3/envs/pkgs_lintr/lib/R/lib/libRblas.so

locale:
 [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_GB.UTF-8        LC_COLLATE=en_GB.UTF-8    
 [5] LC_MONETARY=en_GB.UTF-8    LC_MESSAGES=en_GB.UTF-8   
 [7] LC_PAPER=en_GB.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] xmlparsedata_1.0.2.9000 testthat_2.1.1         

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.1        rstudioapi_0.10   xml2_1.2.0        magrittr_1.5     
 [5] usethis_1.5.1     devtools_2.1.0    pkgload_1.0.2     R6_2.4.0         
 [9] rlang_0.4.0       tools_3.5.1       pkgbuild_1.0.3    sessioninfo_1.1.1
[13] cli_1.1.0         withr_2.1.2       remotes_2.1.0     assertthat_0.2.1 
[17] digest_0.6.20     rprojroot_1.3-2   crayon_1.3.4      processx_3.4.0   
[21] callr_3.3.0       fs_1.3.1          ps_1.3.0          praise_1.0.0     
[25] memoise_1.1.0     glue_1.3.1        compiler_3.5.1    desc_1.2.0       
[29] backports_1.1.4   prettyunits_1.0.2

[russHyde]

Closed in #6