acid-r-package

name	acid-r-package
description	Acid Genomics R package development conventions — per-project air.toml, global ~/.lintr only, roxygen2 8.x @importFrom split, S4 linter tuning, AcidDevTools::check() gate. Use when writing or checking an acidgenomics R package, configuring air/lintr, or fixing roxygen/lint failures.

Acid Genomics R Package Development Conventions

Applies to all packages under ~/git/personal/r-<pkgname> (acidgenomics org). Reference implementation: pointillism 0.8.0 (2026-06-20).

Tooling Stack

Tool	Config	Notes
formatter	air.toml (per-project)	No global config — air walks up from file; must exist at package root
linter	~/.lintr (global, chezmoi-managed)	No per-project .lintr — project file replaces global, never merges
docs	roxygen2 8.0.0	Single-line @importFrom required (see below)
check	AcidDevTools::check()	Wraps lint + rcmdcheck + BiocCheck

air.toml

All packages carry this identical 8-line file. The canonical source is ~/git/personal/r-pipette/air.toml. Copy verbatim — do not vary any field:

[format]
default-exclude = false
exclude = []
indent-style = "space"
indent-width = 4
line-ending = "lf"
line-width = 80
persistent-line-breaks = true

Air has no global config fallback — per-project air.toml is required and must be git-tracked (not gitignored). Untracked air.toml is invisible to fresh clones and koopa app r publish.

~/.lintr (chezmoi source: opt/dotfiles/chezmoi/dot_lintr)

Single global file; no per-project .lintr files — any local .lintr in a package directory silently replaces the global rather than merging. Remove with git rm -f .lintr on all packages.

To change ~/.lintr: edit opt/dotfiles/chezmoi/dot_lintr, then:

chezmoi apply --source=~/.local/share/koopa/opt/dotfiles/chezmoi ~/.lintr

Current critical settings (2026-06-19)

# Disabled — S4 @importFrom symbols cause ~200 false positives:
object_usage_linter = NULL,

# NOT in the config (removed — S4 method args shadow base exports):
# object_overwrite_linter  ← opt-in linter, do NOT add it

# NOT in the config (removed — S4 class name quoting is required):
# keyword_quote_linter  ← produces ~100 false positives in S4 code

# Object naming: allow camelCase, CamelCase, dotted.case, and as.* coerce generics:
object_name_linter(
    styles = c("camelCase", "CamelCase", "dotted.case"),
    regexes = c("^as\\.")   # S4 coerce generics (e.g. as.DataFrame)
),

# Complexity limit bumped from default 15 to 45:
cyclocomp_linter(complexity_limit = 45L),

DCF format rule

exclusions: key must appear on the line immediately after the closing ) of the linters_with_defaults(...) block — no blank line between them. A blank line starts a new DCF record and the exclusions key is silently dropped.

lintr parser crashes on Unicode-escaped named vector keys

lintr 3.3 crashes (subscript out of bounds) when parsing files containing "\uXXXX" = value syntax in named vector literals. This is a lintr bug.

Fix: restructure using setNames() with separate object and nm args, using actual UTF-8 characters in nm — or namespace with base::setNames().

## BAD (crashes lintr 3.3):
myMap <- c("Α" = "Alpha", "Β" = "Beta")

## GOOD (lintr-safe):
myMap <- setNames(
    object = c("Alpha", "Beta"),
    nm     = c("Α", "Β")           # actual UTF-8, not \uXXXX escapes
)

Note: setNames is in base R and requires no @importFrom. Do NOT write @importFrom base setNames — base does not export setNames in the @importFrom sense and roxygen2 will warn.

.gitignore Convention

Per-package .gitignore should be minimal. The global ~/.config/git/ignore (chezmoi-managed) covers: .RData, .Rcheck, .Rhistory, .Rproj.user, doc/, docs/, tests/testthat/_problems/.

Standard per-package .gitignore:

# This file intentionally minimal — see ~/.config/git/ignore for global patterns.

Exception — packages with committed test data (e.g. r-acidtest):

# This file intentionally minimal — see ~/.config/git/ignore for global patterns.
!data/
!data/*.rda
!data-raw/

Do NOT include .RData, .Rcheck, .Rhistory, .Rproj.user, or docs/ in per-package .gitignore — they are in the global.

DESCRIPTION Conventions

Config/roxygen2/version: 8.0.0      # NOT RoxygenNote: 7.3.x
Roxygen: list(markdown = TRUE)
Config/testthat/edition: 3
Config/testthat/parallel: true
License: Apache License (>= 2)      # NOT AGPL-3; NOT "| file LICENSE"

Run devtools::document() last (after all hand-edits) so it regenerates man/ and NAMESPACE over a clean state.

License Files

Apache-licensed packages use LICENSE.md (markdown, from usethis::use_apache_license()) — not a plain LICENSE file.

In .Rbuildignore: ^LICENSE\.md$ (not ^LICENSE$).

The koopa-r-release skill covers the full relicensing procedure.

README Canonical Format

Header: line 3 must have both badges in this order — bioconda first, lifecycle second. Use https:// in all badge links; no ?style=flat:

[![Install with Bioconda](https://img.shields.io/badge/install%20with-bioconda-brightgreen.svg)](https://bioconda.github.io/recipes/r-<pkg>/README.html) ![Lifecycle: stable](https://img.shields.io/badge/lifecycle-stable-brightgreen.svg)

Conda install block (after R install block):

### [Conda][] method

Configure [Conda][] to use the [Bioconda][] channels.

```sh
# Don't install recipe into base environment.
name='r-<pkg>'
conda create --name="$name" "$name"
conda activate "$name"
R

Link refs (before License section):
```markdown
[bioconda]: https://bioconda.github.io/
[conda]: https://docs.conda.io/

License section (always last):

## License

Apache-2.0 — Copyright <YEAR> Acid Genomics LLC — see [LICENSE.md](LICENSE.md).

Copyright year = year of first git commit:

git log --all --reverse --format="%ad" --date=format:"%Y" | head -1

roxygen2 8.x — @importFrom Format

Breaking change from 7.x: each @importFrom tag must be a single source line. Multi-line continuation (#' wrapping) is an error.

But line_length_linter fires at 80 chars. Solution: split into multiple separate @importFrom tags for the same package — one logical group per line:

## OK (one tag per line, each ≤80 chars):
#' @importFrom BiocGenerics as.data.frame cbind counts counts<- do.call lapply
#' @importFrom BiocGenerics normalize organism organism<- sapply

## NOT OK (multi-line continuation — roxygen2 8.x error):
#' @importFrom BiocGenerics as.data.frame cbind counts counts<- do.call lapply
#' normalize organism organism<-

Never use # nolint on #' comment lines — roxygen2 8.x parses # and nolint as additional function names to import.

setGeneric(name = "PascalCase") — object_name_linter False Positive

object_name_linter fires on the string value passed to setGeneric(name = "SeuratMarkers") because it looks like a PascalCase variable. These are S4 generic names and cannot be renamed. Suppress with # nolint on the name = line only:

setGeneric(
    name = "SeuratMarkers", # nolint
    ...
)

S4 Method Argument Order — function_argument_linter

function_argument_linter requires arguments without defaults to come before arguments with defaults. For S4 method dispatchers that use formals() to set defaults after the function definition, give the argument an explicit sentinel default in the signature to satisfy lintr:

## BAD — lintr sees method as having required arg after optional:
`correlation,matrix,missing` <- function(x, y = NULL, method) { ... }
formals(`correlation,matrix,missing`)[["method"]] <- .method

## GOOD — explicit default satisfies lintr; formals() still overrides at load:
`correlation,matrix,missing` <- function(x, y = NULL, method = .method) { ... }
formals(`correlation,matrix,missing`)[["method"]] <- .method

AcidGenomes API Changes (≥ 0.8.x)

makeTxToGeneFromEnsembl() was removed. Build a TxToGene from Ensembl with:

gr <- AcidGenomes::makeGRangesFromEnsembl(
    organism    = "Homo sapiens",
    level       = "transcripts",
    genomeBuild = "GRCh38",
    release     = 87L,
    ignoreVersion = TRUE
)
tx2gene <- AcidGenomes::TxToGene(gr)

AcidDevTools::check() — Full Pre-Release Gate

AcidDevTools::check(
    path      = "~/git/personal/r-<pkg>",
    lints     = TRUE,
    urls      = FALSE,
    cran      = FALSE,
    biocCheck = TRUE
)

Gate order: dependency check → lintr → urlchecker (urls=TRUE only) → rcmdcheck → BiocCheck (when biocViews present).

Always run from a temp directory to prevent *.Rcheck/ from being created in your current working directory:

old <- setwd(tempdir())
on.exit(setwd(old))
AcidDevTools::check(path = path.expand("~/git/personal/r-<pkg>"), ...)

check() fails if any Suggests package is missing, even before running lints. Install all Suggests before running the gate.

Parallel test failures under rcmdcheck: Config/testthat/parallel: true can crash in rcmdcheck's subprocess on macOS (fork resource limits). Run TESTTHAT_PARALLEL=false as an env override — keep the DESCRIPTION setting as-is:

Sys.setenv(TESTTHAT_PARALLEL = "false")
AcidDevTools::check(...)

valid() test requires internet: AcidDevTools::valid() calls utils::old.packages() which needs network. Guard with skip_if_not(goalie::hasInternet()).

keyword_quote_linter — Named List Elements

This linter was removed from ~/.lintr due to pervasive S4 false positives (S4 class definitions require quoted strings in contains, slots, prototype — lintr cannot distinguish these from cosmetic quoting). The note below is for reference only, in case it is re-enabled:

Quoted names in list(...) fire when the name is a valid R symbol:

list("geneId" = val)    # BAD — fires linter
list(geneId = val)      # GOOD

Exception: switch() EXPR values are strings and must stay quoted.

leftJoin — Type Coercion Before Join

AcidPlyr::leftJoin() enforces strict type matching on by columns. Coerce geneId to character on both sides:

markers[["geneId"]] <- as.character(mcols(ranges)[["geneId"]])
known[["geneId"]]   <- as.character(known[["geneId"]])
x <- leftJoin(x, known, by = "geneId")

future::plan() — Defunct Backends

"multiprocess" was removed in future 1.32. Use "multicore":

if (isTRUE(future::supportsMulticore()) && !is.null(workers)) {
    future::plan("multicore", workers = workers)
}

Running Tests

Always set locale to avoid S4 method dispatch encoding warnings:

LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 \
TESTTHAT_PARALLEL=false \
  R -q -e 'devtools::load_all("."); testthat::test_dir("tests/testthat")'

Config/testthat/parallel: true stays in DESCRIPTION — TESTTHAT_PARALLEL=false is a runner-only override for debuggable serial output.

@importFrom base — Do Not Use

base package functions (setNames, inherits, which, etc.) are always available in R without explicit import. Never write @importFrom base <fn>:

• roxygen2 warns: "Excluding unknown export from base: setNames"
• The function is unavailable to @importFrom regardless

Use the function unqualified. If namespace_linter flags it incorrectly, that is a lintr false positive — add # nolint to that specific line.

Version Bump Rule

If a package's Version: in DESCRIPTION matches what's already in src/contrib/PACKAGES on S3, bump the patch before publishing — S3 overwrites but the PACKAGES index must show a new version to be useful.

README, .gitignore, and air.toml changes do not require a version bump or koopa app r publish — documentation-only PRs can be merged without republishing to S3.

See koopa-r-release for the complete publish workflow.