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Fix fread clipboard handling on Windows (fixes #1292) #7640

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Fix fread clipboard handling on Windows (fixes #1292) #7640

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546de99
Fix fread clipboard handling on Windows (fixes #1292)
AmanKashyap0807 Feb 9, 2026
c68136d
addressing linting
AmanKashyap0807 Feb 9, 2026
43b8a22
Tweak fread clipboard checks and error handling on Windows
AmanKashyap0807 Feb 17, 2026
b5a2a7c
Add Linux (X11/Wayland) and macOS clipboard support to fread
AmanKashyap0807 Feb 19, 2026
a8abf6c
Merge branch 'master' into fix-fread-clipboard-issue1292
AmanKashyap0807 Feb 19, 2026
6c34cba
correct wl-paste redundancy and replace stopf with warning for non su…
AmanKashyap0807 Feb 19, 2026
b95ca4c
fix linter warning of CI workflow
AmanKashyap0807 Feb 19, 2026
5e33fe9
Address review feedback for fread clipboard support
AmanKashyap0807 Feb 22, 2026
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2 changes: 2 additions & 0 deletions NEWS.md
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Expand Up @@ -38,6 +38,8 @@

4. `rowwiseDT()` now provides a helpful error message when a complex object that is not a list (e.g., a function) is provided as a cell value, instructing the user to wrap it in `list()`, [#7219](https://github.com/Rdatatable/data.table/issues/7219). Thanks @kylebutts for the report and @venom1204 for the fix.

5. `fread()` now recognizes Windows clipboard tokens such as `clipboard`, avoiding shell execution failures, [#1292](https://github.com/Rdatatable/data.table/issues/1292). Thanks @mbacou for the report and @AmanKashyap0807 for the fix.

### Notes

1. {data.table} now depends on R 3.5.0 (2018).
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23 changes: 23 additions & 0 deletions R/fread.R
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Expand Up @@ -63,6 +63,29 @@ yaml=FALSE, tmpdir=tempdir(), tz="UTC")
# input is data itself containing at least one \n or \r
} else if (startsWith(input, " ")) {
stopf("input= contains no \\n or \\r, but starts with a space. Please remove the leading space, or use text=, file= or cmd=")
} else if (grepl("^clipboard(-[0-9]+)?$", tolower(input))) {
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is_windows = identical(.Platform$OS.type, "windows")
if (is_windows) {
clip = tryCatch(utils::readClipboard(), error = identity)
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@ben-schwen ben-schwen Feb 16, 2026

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we don't normally use namespacing for functions from utils, see e.g. head/tail

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@MichaelChirico MichaelChirico Feb 16, 2026

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we don't have blanket utils import so it'll need to be included:

data.table/NAMESPACE

Line 148 in 1bd88cb

importFrom(utils, capture.output, contrib.url, download.file, flush.console, getS3method, head, packageVersion, tail, untar, unzip)

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@AmanKashyap0807 AmanKashyap0807 Feb 17, 2026

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readClipboard() is documented as Windows‑only in the utils::clipboard help:
https://search.r-project.org/R/refmans/utils/help/clipboard.html
There are also reports on non‑Windows where readClipboard() simply isn’t available even with utils loaded,
(https://stackoverflow.com/questions/24365249/readclipboard-removed-from-utils-package)
so importing it unconditionally in NAMESPACE risks errors when the package is loaded on those platforms. That’s why I kept utils::readClipboard() inside the Windows guard.

Regarding head/tail, data.table::last() has a small fallback that explicitly calls utils::head and utils::tail instead of using them unqualified everywhere, and that pattern was in my mind when I treated utils::readClipboard() as a similar Windows‑specific special case. I’m happy to change this to plain readClipboard() with a NAMESPACE import if you prefer and are confident it behaves well on non‑Windows platforms.

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# for errors due to permissions, clipboard locked or system errors
if (inherits(clip, "error")) {
stopf("Reading clipboard failed on Windows: %s", conditionMessage(clip))
}
if (!length(clip) || !all(nzchar(trimws(clip)))) {
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stopf("Clipboard is empty.")
}
tmpFile = tempfile(tmpdir=tmpdir)
on.exit(unlink(tmpFile), add=TRUE)
tryCatch({
writeLines(paste(clip, collapse="\n"), tmpFile, useBytes=TRUE)
file = tmpFile
}, error = function(e) {
stopf("Writing clipboard to temporary file failed: %s. Check tmpdir=%s.", conditionMessage(e), tmpdir)
})
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} else {
# Note: macOS (pbpaste) and Linux (xclip/xsel) support discussed in #1292
stopf("Clipboard reading is supported on Windows only.")
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}
} else if (length(grep(' ', input, fixed=TRUE)) && !file.exists(gsub("^file://", "", input))) { # file name or path containing spaces is not a command. file.exists() doesn't understand file:// (#7550)
cmd = input
if (input_has_vars && getOption("datatable.fread.input.cmd.message", TRUE)) {
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8 changes: 8 additions & 0 deletions inst/tests/tests.Rraw
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Expand Up @@ -21515,3 +21515,11 @@ test(2365.1, melt(df_melt, id.vars=1:2), melt(dt_melt, id.vars=1:2))
df_dcast = data.frame(a = c("x", "y"), b = 1:2, v = 3:4)
dt_dcast = data.table(a = c("x", "y"), b = 1:2, v = 3:4)
test(2365.2, dcast(df_dcast, a ~ b, value.var = "v"), dcast(dt_dcast, a ~ b, value.var = "v"))

# Test fread clipboard input on Windows (issue #1292)
if (.Platform$OS.type == "windows") local({
temp <- c("a\tb", "1\t2")
utils::writeClipboard(temp)
on.exit(utils::writeClipboard(""), add = TRUE)
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@aitap aitap Mar 3, 2026

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I'm afraid there's no portable way to test this without violating CRAN policy:

Packages should not write in the user’s home filespace (including clipboards)

'https://cran.r-project.org/src/contrib/PACKAGES.in' |> url() |> read.dcf() |> _[,'X-CRAN-Comment'] |> grep(pattern = 'clipb', value = TRUE)
# [1] "Archived on 2019-10-16 for policy violation.\n\nSometimes attempts to write to the clipboard."
# [2] "Archived on 2019-01-06 for policy violation.\n\nwriting to clipboard hung the check run."

Emptying the clipboard afterwards is not enough, as it could previously contain something else, e.g., an image, which we have no way to read and restore later.

test(2366, fread("clipboard-128"), data.table(a = 1L, b = 2L))
})
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