Migration guide for XML package

[nuest]

The package XML is orphaned on CRAN. There are still updates from time to time, but I am unsure whether my current problem, where I get a segfault the moment that Rccp is loaded, will be fixed.

Is there a migration guide for users to switch to xml2 from XML or are you aware of any packages that did this?

[jennybc]

There is no such migration guide within the xml2 docs. There are definitely packages that have done this, but I can't think of any off the top of my head. You might be able to turn some up with clever GitHub searches. But it really sounds like a good topic for https://community.rstudio.com or even an #rstats tweet.

[nuest]

Thanks for the ideas, I went ahead with one and two. Would you mind leaving this issue open for a little bit, potentially collect some more information?

The migration will be a big step for my package, so I'll need a bit to schedule that, and it'll probably be so much work that a couple of hours to write down lessons learned are not a big addition. Still I'd hope to find some other contributors to such a migration guide and collect as much information here as possible.

• GitHub search: https://github.com/search?l=R&q=XML+xml2&type=Issues (also with added search terms "change", "orphaned", ..)
  • PRs/commits
    • https://github.com/quanteda/quanteda/pull/1364/files (4 changes)
    • https://github.com/quanteda/readtext/pull/128/files (~ 10 changes)
    • andrie/sss@8787dd0 (~10 changes)
    • https://github.com/cpsievert/rdom/pull/14/files (2 changes)
  • https://github.com/USGS-R/geoknife/pull/362/files (> 20 changes, also using whisker)
  • r-cas/ryacas@e319542 (~ 10 changes)
  • cloudyr/aws.alexa@5f5441f (small)
  • plan/issue only
    • xml2 instead of XML pensoft/ropenbio#2
    • Switch from XML to xml2 andrewheiss/colourlovers#6
    • Use xml2 instead of XML? nuno-agostinho/psichomics#135
    • switch to xml2 cloudyr/MTurkRGUI#4
    • Remove dependency on XML andrie/miniCRAN#75 (wants to drop completely)
• RStudio Community: https://community.rstudio.com/t/migrate-to-xml2-from-xml/23070

Process/Notes

• itdepends is very useful for finding all references to functions of the package, see https://speakerdeck.com/jimhester/it-depends?slide=39

[jennybc]

Here's are some of the main PRs where the switch happened in googlesheets:

• Switch to xml2 jennybc/googlesheets#102
• use xml2 to create/mutate xml jennybc/googlesheets#246
• there were a lot of other smaller commits here and there along the way

[nuest]

I just published my notes on the transition to xml2 in this gist:
https://gist.github.com/nuest/3ed3b0057713eb4f4d75d11bb62f2d66

The source code changes are best seen via the commits mentioning the issue 52North/sos4R#42

The notes include a table listing the related functions, and things I could "automate" with regexes, and changes I did manually. It's pretty raw, not a friendly "guide" yet. I'm open for feedback and suggestions how to proceed here. Looking at the large number of packages depending on XML, an orphaned package, it might be worth reaching out to some of them and advertise xml2.

[georgevbsantiago]

I currently use the XML package only because of the readHTMLTable function. The xml2 package does not have a function to read tables in the HTML files, correct? I've already tried using the rvest :: html_table function, but readHTMLTable is 10x faster and produces a cleaner data table.

I put an HTML example in the attached file. The table "id =' tableResult" for test

html Table.zip

[jimhester]

I think a useful TDD task would be to take @nuest's guide and turning parts of it into a vignette / pkgdown article.

[georgevbsantiago]

Atualmente, uso o pacote XML apenas por causa da readHTMLTablefunção. O pacote xml2 não tem função de leitura de tabelas nos arquivos HTML, correto? Já tentei usar a função rvest :: html_table, mas readHTMLTableé 10x mais rápida e produz uma tabela de dados mais limpa.

Coloquei um exemplo de HTML no arquivo anexado. A tabela "id = 'tableResult" para teste

html Table.zip

@hadley made a spectacular improvement in the performance of the rvest::html_table function!!! Aqui

You may want to include the rvest::html_table function in the tutorial Switching from XML to xml2