Merge pull request #7 from maelle/git-add-patch

feat: add an example for git patch

NAMESPACE

@@ -3,3 +3,4 @@
 export(exo_committed_to_main)
 export(exo_latest_message)
 export(exo_one_small_change)
+export(exo_split_changes)

R/split-changes.R

@@ -0,0 +1,66 @@
+#' "Hey I'd like to split these changes to the same file in several commits!"
+#'
+#' @description
+#' I made many edits to a file, in different places.
+#' This is too much for a commit, since small commits are best practice.
+#' I need to add the changes to Git bit by bit.
+#' The tool for that is `git add --patch`, also available as `git add -p`.
+#' If all your changes are presented to you as one chunk by `git add --patch`,
+#' choose the "s" option for splitting.
+#' See https://git-scm.com/book/en/v2/Git-Tools-Interactive-Staging#_staging_patches.
+#'
+#' Note that patch is also an option for `git commit`, if you prefer so.
+#'
+#'
+#' @inheritParams exo_one_small_change
+#'
+#' @return The path to the new project
+#' @export
+#'
+#' @examplesIf interactive()
+#' parent_path <- withr::local_tempdir()
+#' path <- exo_split_changes(parent_path = parent_path)
+exo_split_changes <- function(parent_path) {
+
+  path <- file.path(parent_path, "split-changes")
+
+  withr::local_options(usethis.quiet = TRUE)
+
+  fs::dir_create(path)
+  original_dir <- getwd()
+
+  withr::local_dir(path)
+  gert::git_init()
+
+  file.copy(
+    system.file("exo_split_changes-Rprofile.R", package = "saperlipopette"),
+    ".Rprofile"
+  )
+
+  usethis::create_project(path = getwd())
+  # Ignore Rproj that might otherwise get edited when we open the project
+  rproj <- fs::dir_ls(glob = "*.Rproj")
+  usethis::local_project(getwd(), force = TRUE)
+  usethis::use_git_ignore(rproj)
+  usethis::use_git_ignore(".Rprofile")
+  gert::git_add("*")
+  git_commit("First commit")
+
+  new_script <- file.path("R", "script.R")
+  fs::file_create(new_script)
+  script_lines <- c("a <- 1", "b <- 2")
+  brio::write_lines(text = script_lines, path = new_script)
+  gert::git_add(new_script)
+  git_commit("feat: add script")
+
+  script_lines <- append(script_lines, "# a comment", after = 0)
+  script_lines <- append(script_lines, c("1/2", "1/3"), after = 2)
+  script_lines <- append(script_lines, c("library(ggplot2)"))
+  brio::write_lines(text = script_lines, path = new_script)
+
+  usethis::local_project(original_dir, force = TRUE)
+
+  cli::cli_alert_info("Follow along in {path}!")
+
+  return(path)
+}

_pkgdown.yml

@@ -2,3 +2,12 @@ url: https://maelle.github.io/saperlipopette/
 template:
   bootstrap: 5
 
+reference:
+- title: Exercises inspired from Oh shit Git!
+  contents:
+  - exo_committed_to_main
+  - exo_latest_message
+  - exo_one_small_change
+- title: Other exercises
+  contents:
+  - exo_split_changes

inst/exo_split_changes-Rprofile.R

@@ -0,0 +1,23 @@
+if (file.exists("~/.Rprofile")) {
+  base::sys.source("~/.Rprofile", envir = environment())
+}
+cli::cli_alert_danger("Hey I'd like to split these changes to the same file in several commits!")
+cli::cli_alert_danger("I want to add my three changes to R/script.R in three commits not one.")
+cli::cli_alert_info("See {.url https://git-scm.com/book/en/v2/Git-Tools-Interactive-Staging#_staging_patches}")
+cli::cli_alert_info("For more help use {.run tip()}")
+
+tip <- function() {
+  cli::cli_li(
+    items = c(
+      "Examine Git staging area.",
+      "{.code git add --patch} to add a first chunk ('s' to split, 'y' to stage the first chunk, 'n' twice to discard the others)",
+      '{.code git commit -m "First change"}',
+      "{.code git add --patch} to add a second chunk ('s' to split, 'y' to stage the first chunk, 'n' once to discard the other)",
+      '{.code git commit -m "Second change"}',
+      "{.code git add *} to add the last chunk",
+      '{.code git commit -m "Third change"}',
+      "Examine Git history."
+    )
+  )
+
+}

tests/testthat/_snaps/split-changes.md

@@ -0,0 +1,8 @@
+# exo_split_changes() works
+
+    Code
+      gert::git_log(repo = path)[["commit"]]
+    Output
+      [1] "2a61d9da6865eb7f7272c9f901f13c1da377a01e"
+      [2] "e227ecc55e421f70b6e30602e6a2eee02aad42e0"
+

tests/testthat/test-split-changes.R

@@ -0,0 +1,7 @@
+test_that("exo_split_changes() works", {
+  rlang::local_options(cli.default_handler = function(msg) invisible(NULL))
+  parent_path <- withr::local_tempdir()
+  path <- exo_split_changes(parent_path = parent_path)
+  expect_equal(fs::path_file(path), "split-changes")
+  expect_snapshot(gert::git_log(repo = path)[["commit"]])
+})