feat: add git_config_get() and git_config_global_get()

Co-Authored-By: Claude Opus 4.6

Author: maelle

NAMESPACE

@@ -28,8 +28,11 @@ export(git_commit_id)
 export(git_commit_info)
 export(git_commit_stats)
 export(git_config)
+export(git_config_get)
 export(git_config_global)
+export(git_config_global_get)
 export(git_config_global_set)
+export(git_config_local_get)
 export(git_config_set)
 export(git_conflicts)
 export(git_diff)

NEWS.md

@@ -1,5 +1,6 @@
 # gert (development version)
 
+- Add `git_config_get()`, `git_config_local_get()`, and `git_config_global_get()` to retrieve a single named config option, returning `NULL` if unset (#267).
 - `git_remote_set_pushurl()` gains an `add` argument to append push URLs instead of replacing them. (@robitalec, #128)
 - Fix `git_info()` for the case when no upstream is configured (@mpage, #263)
 - `git_branch_create()`: `force` now also applies to the checkout step, allowing branch creation even when local changes would be overwritten (@MichaelChirico, #177).

R/config.R

@@ -4,14 +4,13 @@
 #' Get or set Git options, as `git config` does on the command line. **Global**
 #' settings affect all of a user's Git operations (`git config --global`),
 #' whereas **local** settings are scoped to a specific repository (`git config
-#' --local`). When both exist, local options always win. Four functions address
-#' the four possible combinations of getting vs setting and global vs. local.
+#' --local`). When both exist, local options always win.
 #'
 #' ```{r echo = FALSE, results = "asis"}
 #' dat <- data.frame(
-#'   local = c("`git_config()`", "`git_config_set()`"),
-#'   global = c("`git_config_global()`", "`git_config_global_set()`"),
-#'   row.names = c("get", "set")
+#'   local = c("`git_config()`", "`git_config_get()`", "`git_config_local_get()`", "`git_config_set()`"),
+#'   global = c("`git_config_global()`", "`git_config_get()`", "`git_config_global_get()`", "`git_config_global_set()`"),
+#'   row.names = c("get all", "get one (local+global)", "get one (local or global only)", "set")
 #' )
 #' knitr::kable(dat, col.names = paste0("**", colnames(dat), "**"))
 #' ```
@@ -21,6 +20,11 @@
 #'   option is determined from global or local config.
 #' * `git_config_global()`: a `data.frame`, as for `git_config()`, except only
 #'   for global Git options.
+#' * `git_config_get()`: the value of the named option considering both local and
+#'   global config (local wins), or `NULL` if unset.
+#' * `git_config_local_get()`: as for `git_config_get()`, but restricted to
+#'   local (repository-level) config only.
+#' * `git_config_global_get()`: as for `git_config_get()`, but for global config only.
 #' * `git_config_set()`, `git_config_global_set()`: The previous value(s) of
 #'   `name` in local or global config, respectively. If this option was
 #'   previously unset, returns `NULL`. Returns invisibly.
@@ -36,15 +40,16 @@
 #'
 #' previous <- git_config_set("aaa.bbb", "ccc", repo = r)
 #' previous
-#' cfg <- git_config(repo = r)
-#' subset(cfg, level == "local")
-#' cfg$value[cfg$name == "aaa.bbb"]
+#' git_config_local_get("aaa.bbb", repo = r)
 #'
 #' previous <- git_config_set("aaa.bbb", NULL, repo = r)
 #' previous
-#' cfg <- git_config(repo = r)
-#' subset(cfg, level == "local")
-#' cfg$value[cfg$name == "aaa.bbb"]
+#' git_config_local_get("aaa.bbb", repo = r)
+#'
+#' # Get a single named option (returns NULL if unset)
+#' git_config_get("aaa.bbb", repo = r)
+#' git_config_set("aaa.bbb", "ccc", repo = r)
+#' git_config_get("aaa.bbb", repo = r)
 #'
 #' unlink(r, recursive = TRUE)
 #'
@@ -53,6 +58,10 @@
 #' git_config_global_set("user.name", "Your Name")
 #' git_config_global_set("user.email", "your@email.com")
 #' git_config_global()
+#'
+#' # Get a single global option (returns NULL if unset)
+#' git_config_global_get("user.name")
+#' git_config_global_get("gert.nonexistent")
 #' }
 #' @export
 #' @family git
@@ -70,10 +79,41 @@ git_config_global <- function() {
   .Call(R_git_config_list, NULL)
 }
 
+#' @export
+#' @rdname git_config
+#' @param name Name of the option to get or set
+git_config_get <- function(name, repo = '.') {
+  cfg <- git_config(repo = repo)
+  if (!name %in% cfg$name) {
+    return(NULL)
+  }
+  cfg$value[cfg$name == name]
+}
+
+#' @export
+#' @rdname git_config
+git_config_local_get <- function(name, repo = '.') {
+  cfg <- git_config(repo = repo)
+  cfg <- cfg[cfg$level == "local", ]
+  if (!name %in% cfg$name) {
+    return(NULL)
+  }
+  cfg$value[cfg$name == name]
+}
+
+#' @export
+#' @rdname git_config
+git_config_global_get <- function(name) {
+  cfg <- git_config_global()
+  if (!name %in% cfg$name) {
+    return(NULL)
+  }
+  cfg$value[cfg$name == name]
+}
+
 #' @export
 #' @rdname git_config
 #' @useDynLib gert R_git_config_set
-#' @param name Name of the option to set
 #' @param value Value to set. Must be a string, logical, number or `NULL` (to
 #'   unset).
 #' @param add if `TRUE`, append a new entry for `name` instead of replacing
@@ -85,8 +125,7 @@ git_config_set <- function(name, value, add = FALSE, repo = '.') {
   }
   repo <- git_open(repo)
   name <- as.character(name)
-  orig_cfg <- git_config(repo = repo)
-  out <- orig_cfg$value[orig_cfg$name == name & orig_cfg$level == "local"]
+  out <- git_config_local_get(name, repo = repo)
   .Call(R_git_config_set, repo, name, value, add)
   if (length(out) > 0) {
     invisible(out)
@@ -98,8 +137,7 @@ git_config_set <- function(name, value, add = FALSE, repo = '.') {
 #' @export
 #' @rdname git_config
 git_config_global_set <- function(name, value, add = FALSE) {
-  orig_cfg <- git_config_global()
-  out <- orig_cfg$value[orig_cfg$name == name]
+  out <- git_config_global_get(name)
   .Call(R_git_config_set, NULL, name, value, add)
   if (length(out) > 0) {
     invisible(out)
@@ -141,9 +179,8 @@ configure_global_user <- function() {
 }
 
 global_user_is_configured <- function() {
-  cfg <- git_config_global()
-  user_name_exists <- any(cfg$name == "user.name")
-  user_email_exists <- any(cfg$name == "user.email")
+  user_name_exists <- !is.null(git_config_global_get("user.name"))
+  user_email_exists <- !is.null(git_config_global_get("user.email"))
   user_name_exists && user_email_exists
 }
 
@@ -164,11 +201,7 @@ global_user_is_configured <- function() {
 #' @examples
 #' user_is_configured()
 user_is_configured <- function(repo = ".") {
-  cfg <- tryCatch(
-    git_config(repo),
-    error = function(e) git_config_global()
-  )
-  user_name_exists <- any(cfg$name == "user.name")
-  user_email_exists <- any(cfg$name == "user.email")
+  user_name_exists <- !is.null(git_config_get("user.name", repo = repo))
+  user_email_exists <- !is.null(git_config_get("user.email", repo = repo))
   user_name_exists && user_email_exists
 }

man/git_config.Rd

@@ -1,14 +1,40 @@
+test_that("git_config_get returns value or NULL", {
+  repo <- git_init(tempfile("gert-tests-config"))
+  on.exit(unlink(repo, recursive = TRUE))
+
+  expect_null(git_config_get("aaa.bbb", repo = repo))
+  git_config_set("aaa.bbb", "ccc", repo = repo)
+  expect_equal(git_config_get("aaa.bbb", repo = repo), "ccc")
+})
+
+test_that("git_config_global_get returns value or NULL", {
+  expect_null(git_config_global_get("gert.nonexistent.option.xyzzy"))
+  # Note: avoid setting/unsetting real global config in tests
+})
+
+test_that("git_config_local_get returns local value or NULL", {
+  repo <- git_init(tempfile("gert-tests-config"))
+  on.exit(unlink(repo, recursive = TRUE))
+
+  expect_null(git_config_local_get("aaa.bbb", repo = repo))
+  git_config_set("aaa.bbb", "ccc", repo = repo)
+  expect_equal(git_config_local_get("aaa.bbb", repo = repo), "ccc")
+  # global-only option should not be visible at local level
+  expect_null(git_config_local_get(
+    "gert.nonexistent.option.xyzzy",
+    repo = repo
+  ))
+})
+
 test_that("local, custom config roundtrip", {
   repo <- git_init(tempfile("gert-tests-config"))
   on.exit(unlink(repo, recursive = TRUE))
 
   orig <- git_config_set("aaa.bbb", "ccc", repo = repo)
   expect_null(orig)
-  cfg <- git_config(repo)
-  expect_equal(cfg$value[cfg$name == "aaa.bbb"], "ccc")
+  expect_equal(git_config_get("aaa.bbb", repo = repo), "ccc")
 
   orig <- git_config_set("aaa.bbb", NULL, repo = repo)
   expect_equal(orig, "ccc")
-  cfg <- git_config(repo)
-  expect_equal(cfg$value[cfg$name == "aaa.bbb"], character())
+  expect_null(git_config_get("aaa.bbb", repo = repo))
 })

tests/testthat/test-config.R

@@ -5,12 +5,23 @@ test_that("git_remote_set_pushurl with add = TRUE appends push URLs", {
 
   git_remote_add("https://example.com/fetch", name = "origin", repo = repo)
 
-  git_remote_set_pushurl("https://example.com/push1", remote = "origin", repo = repo)
-  git_remote_set_pushurl("https://example.com/push2", remote = "origin", add = TRUE, repo = repo)
+  git_remote_set_pushurl(
+    "https://example.com/push1",
+    remote = "origin",
+    repo = repo
+  )
+  git_remote_set_pushurl(
+    "https://example.com/push2",
+    remote = "origin",
+    add = TRUE,
+    repo = repo
+  )
 
-  cfg <- git_config(repo = repo)
-  pushurls <- cfg$value[cfg$name == "remote.origin.pushurl"]
-  expect_setequal(pushurls, c("https://example.com/push1", "https://example.com/push2"))
+  pushurls <- git_config_get("remote.origin.pushurl", repo = repo)
+  expect_setequal(
+    pushurls,
+    c("https://example.com/push1", "https://example.com/push2")
+  )
 })
 
 test_that("git_remote_set_pushurl without add replaces push URL", {
@@ -20,11 +31,18 @@ test_that("git_remote_set_pushurl without add replaces push URL", {
 
   git_remote_add("https://example.com/fetch", name = "origin", repo = repo)
 
-  git_remote_set_pushurl("https://example.com/push1", remote = "origin", repo = repo)
-  git_remote_set_pushurl("https://example.com/push2", remote = "origin", repo = repo)
+  git_remote_set_pushurl(
+    "https://example.com/push1",
+    remote = "origin",
+    repo = repo
+  )
+  git_remote_set_pushurl(
+    "https://example.com/push2",
+    remote = "origin",
+    repo = repo
+  )
 
-  cfg <- git_config(repo = repo)
-  pushurls <- cfg$value[cfg$name == "remote.origin.pushurl"]
+  pushurls <- git_config_get("remote.origin.pushurl", repo = repo)
   expect_equal(pushurls, "https://example.com/push2")
 })