Adding error handling to git_remote http requests (Resolves #625)

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: remotes
 Title: R Package Installation from Remote Repositories, Including 'GitHub'
-Version: 2.4.0.9000
+Version: 2.4.0.9001
 Authors@R: c(
     person("Jim", "Hester", , "jim.hester@rstudio.com", role = c("aut", "cre")),
     person("Gábor", "Csárdi", , "csardi.gabor@gmail.com", role = c("aut")),

NEWS.md

@@ -1,5 +1,6 @@
 # remotes (development version)
 
+* Using `remote_package_name.git2r_remote` and `remote_package_name.xgit_remote`, http responses returning an invalid `DESCRIPTION` or that redirect to another page will now fallback to return `NA` instead of throwing an error when trying to parse the unexpected content (#628, @dgkf).
 * Fix regex that breaks git protocol in `git_remote` (@niheaven #630).
 
 # remotes 2.4.0

R/install-git.R

@@ -146,9 +146,14 @@ remote_package_name.git2r_remote <- function(remote, ...) {
   description_path <- paste0(collapse = "/", c(remote$subdir, "DESCRIPTION"))
 
   if (grepl("^https?://", remote$url)) {
+    # assumes GitHub-style "<repo>/raw/<ref>/<path>" url
     url <- build_url(sub("\\.git$", "", remote$url), "raw", remote_sha(remote, ...), description_path)
-    download(tmp, url)
-    read_dcf(tmp)$Package
+    tryCatch({
+      download(tmp, url)
+      read_dcf(tmp)$Package
+    }, error = function(e) {
+      NA_character_
+    })
   } else {
     # Try using git archive --remote to retrieve the DESCRIPTION, if the protocol
     # or server doesn't support that return NA

tests/testthat/test-install-git.R

@@ -193,6 +193,22 @@ test_that("remote_package_name.git2r_remote returns the package name if it exist
   url <- "https://github.com/igraph/rigraph.git@master"
   remote <- git_remote(url, git = "git2r")
   expect_equal(remote_package_name(remote), "igraph")
+
+  # works for gitlab urls
+  url <- "https://gitlab.com/r-lib-grp/test-pkg.git"
+  remote <- git_remote(url, git = "git2r")
+  expect_equal(remote_package_name(remote), "test123")
+
+  # safely returns NA when DESCRIPTION url is not accessible
+  # (condition emitted due to inaccessible git remote for remote_sha during testing)
+  url <- "https://gitlab.com/r-lib-grp/fake-private-repo.git"
+  remote <- git_remote(url, git = "git2r")
+  err <- tryCatch(remote_sha(remote), error = function(e) e)
+  expect_error(  # expect same error as calling remote_sha directly
+    expect_equal(remote_package_name(remote), NA_character_),
+    class = class(err),
+    label = conditionMessage(err)
+  )
 })
 
 test_that("remote_package_name.xgit_remote returns the package name if it exists", {