diff-methods function

Changes between commits, trees, working tree, etc.

## S3 method for class 'git_repository'
diff(
  x,
  index = FALSE,
  as_char = FALSE,
  filename = NULL,
  context_lines = 3,
  interhunk_lines = 0,
  old_prefix = "a",
  new_prefix = "b",
  id_abbrev = NULL,
  path = NULL,
  max_size = NULL,
  ...
)

## S3 method for class 'git_tree'
diff(
  x,
  new_tree = NULL,
  index = FALSE,
  as_char = FALSE,
  filename = NULL,
  context_lines = 3,
  interhunk_lines = 0,
  old_prefix = "a",
  new_prefix = "b",
  id_abbrev = NULL,
  path = NULL,
  max_size = NULL,
  ...
)

Arguments

• x: A git_repository object or the old git_tree

  object to compare to.

• index: - When object equals a git_repository: Whether to compare the index to HEAD. If FALSE (the default), then the working tree is compared to the index.

  • When object equals a git_tree: Whether to use the working directory (by default), or the index (if set to TRUE) in the comparison to object.

• as_char: logical: should the result be converted to a character string?. Default is FALSE.

• filename: If as_char is TRUE, then the diff can be written to a file with name filename (the file is overwritten if it exists). Default is NULL.

• context_lines: The number of unchanged lines that define the boundary of a hunk (and to display before and after). Defaults to 3.

• interhunk_lines: The maximum number of unchanged lines between hunk boundaries before the hunks will be merged into one. Defaults to 0.

• old_prefix: The virtual "directory" prefix for old file names in hunk headers. Default is "a".

• new_prefix: The virtual "directory" prefix for new file names in hunk headers. Defaults to "b".

• id_abbrev: The abbreviation length to use when formatting object ids. Defaults to the value of 'core.abbrev' from the config, or 7 if NULL.

• path: A character vector of paths / fnmatch patterns to constrain diff. Default is NULL which include all paths.

• max_size: A size (in bytes) above which a blob will be marked as binary automatically; pass a negative value to disable. Defaults to 512MB when max_size is NULL.

• ...: Not used.

• new_tree: The new git_tree object to compare, or NULL. If NULL, then we use the working directory or the index (see the index argument).

Returns

A git_diff object if as_char is FALSE. If as_char is TRUE and filename is NULL, a character string, else NULL.

Line endings

Different operating systems handle line endings differently. Windows uses both a carriage-return character and a linefeed character to represent a newline in a file. While Linux and macOS use only the linefeed character for a newline in a file. To avoid problems in your diffs, you can configure Git to properly handle line endings using the core.autocrlf

setting in the Git config file, see the Git documentation (https://git-scm.com/).

Examples

## Not run:

## Initialize a repository
path <- tempfile(pattern="git2r-")
dir.create(path)
repo <- init(path)

## Config user
config(repo, user.name = "Alice", user.email = "alice@example.org")

## Create a file, add, commit
writeLines("Hello world!", file.path(path, "test.txt"))
add(repo, "test.txt")
commit(repo, "Commit message")

## Change the file
writeLines(c("Hello again!", "Here is a second line", "And a third"),
           file.path(path, "test.txt"))

## diff between index and workdir
diff_1 <- diff(repo)
summary(diff_1)
cat(diff(repo, as_char=TRUE))

## Diff between index and HEAD is empty
diff_2 <- diff(repo, index=TRUE)
summary(diff_2)
cat(diff(repo, index=TRUE, as_char=TRUE))

## Diff between tree and working dir, same as diff_1
diff_3 <- diff(tree(commits(repo)[[1]]))
summary(diff_3)
cat(diff(tree(commits(repo)[[1]]), as_char=TRUE))

## Add changes, diff between index and HEAD is the same as diff_1
add(repo, "test.txt")
diff_4 <- diff(repo, index=TRUE)
summary(diff_4)
cat(diff(repo, index=TRUE, as_char=TRUE))

## Diff between tree and index
diff_5 <- diff(tree(commits(repo)[[1]]), index=TRUE)
summary(diff_5)
cat(diff(tree(commits(repo)[[1]]), index=TRUE, as_char=TRUE))

## Diff between two trees
commit(repo, "Second commit")
tree_1 <- tree(commits(repo)[[2]])
tree_2 <- tree(commits(repo)[[1]])
diff_6 <- diff(tree_1, tree_2)
summary(diff_6)
cat(diff(tree_1, tree_2, as_char=TRUE))

## Binary files
set.seed(42)
writeBin(as.raw((sample(0:255, 1000, replace=TRUE))),
         con=file.path(path, "test.bin"))
add(repo, "test.bin")
diff_7 <- diff(repo, index=TRUE)
summary(diff_7)
cat(diff(repo, index=TRUE, as_char=TRUE))
## End(Not run)