onLoad.R

# nocov start

.unsafe.opt = function() {
  if (!is.null(getOption("datatable.nomatch")))
    stopf("Option 'datatable.nomatch' is defined but is now ignored. Please see note 11 in v1.12.4 NEWS (Oct 2019), and note 14 in v1.14.2.")
}

.Last.updated = vector("integer", 1L) # exported variable; number of rows updated by the last := or set(), #1885

.onLoad = function(libname, pkgname) {
  session_r_version = base::getRversion()
  # Runs when loaded but not attached to search() path; e.g., when a package just Imports (not Depends on) data.table
  if (!exists("test.data.table", .GlobalEnv, inherits=FALSE)) {
    # check when installed package is loaded but skip when developing the package with cc()
    dllV = if (is.loaded("CdllVersion",PACKAGE="data_table")) .Call(CdllVersion) else "before 1.12.0"
    RV = as.character(packageVersion("data.table"))
    if (dllV != RV) {
      dll = if (.Platform$OS.type=="windows") "dll" else "so"
      # https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17478
      # TODO(R>=4.0.0): Remove or adjust this message once we're sure all users are unaffected
      stopf("The data_table.%s version (%s) does not match the package (%s). Please close all R sessions to release the old %s and reinstall data.table in a fresh R session. Prior to R version 3.6.0 patched, R's package installer could leave a package in an apparently functional state where new R code was calling old C code silently: https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17478. Once a package is in this mismatch state it may produce wrong results silently until you next upgrade the package. This mismatch between R and C code can happen with any package not just data.table. It is just that data.table has added this check.", dll, dllV, RV, toupper(dll))
    }
    builtPath = system.file("Meta", "package.rds", package="data.table")
    if (builtPath != "" && !identical(session_r_version>="4.0.0", (build_r_version <- readRDS(builtPath)$Built$R)>="4.0.0")) {
      stopf("This is R %s but data.table has been installed using R %s. The major version must match. Please reinstall data.table.", session_r_version, build_r_version)
      # the if(R>=4.0.0) in NAMESPACE when registering S3 methods rbind.data.table and cbind.data.table happens on install; #3968
    }
  }

  # c|rbind S3 dispatch now works in R-devel from Sep 2019; #3948 and FAQ 2.24, and R-devel is 4.0.0 as of now. I wanted to test
  # for the presence of the R fix here rather than hard code a version number. But in this case the S3method registration needs to
  # be conditional too: registering the S3 methods in R before 4.0.0 causes this workaround to no longer work. However, the R
  # syntax available to use in NAMESPACE is very limited (can't call data.table() in it in a capability test, for example).
  # This version number ("4.0.0") must be precisely the same as used in NAMESPACE; see PR for #3948.
  if (session_r_version < "4.0.0") {
    # continue to support R<4.0.0
    # If R 3.6.2 (not yet released) includes the c|rbind S3 dispatch fix, then this workaround still works.
    tt = base::cbind.data.frame
    ss = body(tt)
    if (class1(ss) != "{") ss = as.call(c(as.name("{"), ss))
    prefix = if (!missing(pkgname)) "data.table::" else ""  # R provides the arguments when it calls .onLoad, I don't in dev/test
    if (!length(grep("data.table", ss[[2L]], fixed = TRUE))) {
      ss = ss[c(1L, NA, 2L:length(ss))]
      ss[[2L]] = parse(text=paste0("if (!identical(class(..1),'data.frame')) for (x in list(...)) { if (inherits(x,'data.table')) return(",prefix,"data.table(...)) }"))[[1L]]
      body(tt)=ss
      (unlockBinding)("cbind.data.frame",baseenv())
      assign("cbind.data.frame",tt,envir=asNamespace("base"),inherits=FALSE)
      lockBinding("cbind.data.frame",baseenv())
    }
    tt = base::rbind.data.frame
    ss = body(tt)
    if (class1(ss) != "{") ss = as.call(c(as.name("{"), ss))
    if (!length(grep("data.table", ss[[2L]], fixed = TRUE))) {
      ss = ss[c(1L, NA, 2L:length(ss))]
      ss[[2L]] = parse(text=paste0("for (x in list(...)) { if (inherits(x,'data.table')) return(",prefix,".rbind.data.table(...)) }"))[[1L]] # fix for #89
      body(tt)=ss
      (unlockBinding)("rbind.data.frame",baseenv())
      assign("rbind.data.frame",tt,envir=asNamespace("base"),inherits=FALSE)
      lockBinding("rbind.data.frame",baseenv())
    }
  }
  if (session_r_version < "3.6.0") { # corresponds to S3method() directive in NAMESPACE
    # no delayed registration support for NAMESPACE; perform it manually
    if (isNamespaceLoaded("knitr")) {
      registerS3method("knit_print", "data.table", knit_print.data.table, envir = asNamespace("knitr"))
    }
    setHook(packageEvent("knitr", "onLoad"), function(...) {
      registerS3method("knit_print", "data.table", knit_print.data.table, envir = asNamespace("knitr"))
    })
    if (isNamespaceLoaded("xfun")) {
      registerS3method("record_print", "data.table", record_print.data.table, envir = asNamespace("xfun"))
    }
    setHook(packageEvent("xfun", "onLoad"), function(...) {
      registerS3method("record_print", "data.table", record_print.data.table, envir = asNamespace("xfun"))
    })
  }

  # Set options for the speed boost in v1.8.0 by avoiding 'default' arg of getOption(,default=)
  # In fread and fwrite we have moved back to using getOption's default argument since it is unlikely fread and fread will be called in a loop many times, plus they
  # are relatively heavy functions where the overhead in getOption() would not be noticed.  It's only really [.data.table where getOption default bit.
  # Improvement to base::getOption() now submitted (100x; 5s down to 0.05s):  https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17394
  opts = list(
    datatable.verbose=FALSE,            # datatable.<argument name>
    datatable.optimize=Inf,             # datatable.<argument name>
    datatable.print.nrows=100L,         # datatable.<argument name>
    datatable.print.topn=5L,            # datatable.<argument name>
    datatable.print.class=TRUE,         # for print.data.table
    datatable.print.rownames=TRUE,      # for print.data.table
    datatable.print.colnames='auto',    # for print.data.table
    datatable.print.keys=TRUE,          # for print.data.table
    datatable.print.trunc.cols=FALSE,   # for print.data.table
    datatable.show.indices=FALSE,       # for print.data.table
    datatable.allow.cartesian=FALSE,    # datatable.<argument name>
    datatable.join.many=TRUE,           # mergelist, [.data.table #4383 #914
    datatable.dfdispatchwarn=TRUE,      # not a function argument
    datatable.warnredundantby=TRUE,     # not a function argument
    datatable.alloccol=1024L,           # argument 'n' of alloc.col. Over-allocate 1024 spare column slots
    datatable.auto.index=TRUE,          # DT[col=="val"] to auto add index so 2nd time faster
    datatable.use.index=TRUE,           # global switch to address #1422
    datatable.prettyprint.char=NULL,    # FR #1091
    datatable.old.matrix.autoname=FALSE # #7145: how data.table(x=1, matrix(1)) is auto-named set to change
  )
  opts = opts[!names(opts) %chin% names(options())]
  options(opts)

  # Test R behaviour that changed in v3.1 and is now depended on
  x = 1L:3L
  y = list(x)
  if (address(x) != address(y[[1L]])) stopf("Unexpected base R behaviour: list(x) has copied x")

  DF = data.frame(a=1:3, b=4:6)
  add1 = address(DF$a)
  add2 = address(DF$b)
  names(DF) = c("A","B")
  add3 = address(DF$A)
  add4 = address(DF$B)
  if (add1!=add3 || add2!=add4) stopf("Unexpected base R behaviour: names<- has copied column contents")

  DF = data.frame(a=1:3, b=4:6)
  add1 = address(DF$a)
  add2 = address(DF$b)
  add3 = address(DF)
  DF[2L, "b"] = 7L  # changed b but not a
  add4 = address(DF$a)
  add5 = address(DF$b)
  add6 = address(DF)
  if (add2==add5) stopf("Unexpected base R behaviour: DF[2,2]<- did not copy column 2 which was assigned to")
  if (add1!=add4) stopf("Unexpected base R behaviour: DF[2,2]<- copied the first column which was not assigned to, too")

  if (add3==add6) warningf("Unexpected base R behaviour: DF[2,2]<- has not copied address(DF)")
  # R could feasibly in future not copy DF's vecsxp in this case. If that changes in R, we'd like to know via the warning
  # because tests will likely break too. The warning will quickly tell R-core and us why, so we can then update.

  .Call(CinitLastUpdated, .Last.updated)  #1885

  invisible()
}

getRversion = function(...) stopf("Reminder to data.table developers: don't use getRversion() internally. Add a behaviour test to .onLoad instead.") # notranslate
# 1) using getRversion() wasted time when R3.0.3beta was released without the changes we expected in getRversion()>"3.0.2".
# 2) R-devel and ourselves may wish to tinker with R-devel, turning on and off features in the same version number. So it's better if data.table doesn't hard code expectations into the version number.
# 3) The discipline of adding a feature test here helps fully understand the change.
# 4) Defining getRversion with a stopf() here helps prevent new switches on getRversion() being added in future. Easily circumvented but the point is to issue the message above.

.onUnload = function(libpath) {
  library.dynam.unload("data_table", libpath)
}

# nocov end