From e4066c04442f86a5a12d492d588e3e82b533053d Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 15 Nov 2023 16:15:47 +0100
Subject: [PATCH 1/2] Fetch specific Git revisions

This is more efficient, and necessary when using shallow=1 with a rev.
---
 src/libfetchers/git.cc       | 5 ++++-
 tests/functional/fetchGit.sh | 4 +---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/libfetchers/git.cc b/src/libfetchers/git.cc
index 7208a0b6d..2fd3fb41e 100644
--- a/src/libfetchers/git.cc
+++ b/src/libfetchers/git.cc
@@ -518,8 +518,11 @@ struct GitInputScheme : InputScheme
 
             if (doFetch) {
                 try {
-                    auto fetchRef = getAllRefsAttr(input)
+                    auto fetchRef =
+                        getAllRefsAttr(input)
                         ? "refs/*"
+                        : input.getRev()
+                        ? input.getRev()->gitRev()
                         : ref.compare(0, 5, "refs/") == 0
                         ? ref
                         : ref == "HEAD"
diff --git a/tests/functional/fetchGit.sh b/tests/functional/fetchGit.sh
index c38cd27eb..4985c7764 100644
--- a/tests/functional/fetchGit.sh
+++ b/tests/functional/fetchGit.sh
@@ -51,9 +51,7 @@ git -C $repo add differentbranch
 git -C $repo commit -m 'Test2'
 git -C $repo checkout master
 devrev=$(git -C $repo rev-parse devtest)
-out=$(nix eval --impure --raw --expr "builtins.fetchGit { url = file://$repo; rev = \"$devrev\"; }" 2>&1) || status=$?
-[[ $status == 1 ]]
-[[ $out =~ 'Cannot find Git revision' ]]
+nix eval --impure --raw --expr "builtins.fetchGit { url = file://$repo; rev = \"$devrev\"; }"
 
 [[ $(nix eval --raw --expr "builtins.readFile (builtins.fetchGit { url = file://$repo; rev = \"$devrev\"; allRefs = true; } + \"/differentbranch\")") = 'different file' ]]
 

From 071f14a0bb25ffa8e5aaf8ad37031d205f49ef7d Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 15 Nov 2023 17:17:07 +0100
Subject: [PATCH 2/2] Don't do shallow fetches over ssh

---
 src/libfetchers/git-utils.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/libfetchers/git-utils.cc b/src/libfetchers/git-utils.cc
index f554dcc5f..19eae0e1d 100644
--- a/src/libfetchers/git-utils.cc
+++ b/src/libfetchers/git-utils.cc
@@ -381,7 +381,9 @@ struct GitRepoImpl : GitRepo, std::enable_shared_from_this<GitRepoImpl>
         };
 
         git_fetch_options opts = GIT_FETCH_OPTIONS_INIT;
-        opts.depth = shallow ? 1 : GIT_FETCH_DEPTH_FULL;
+        // FIXME: for some reason, shallow fetching over ssh barfs
+        // with "could not read from remote repository".
+        opts.depth = shallow && parseURL(url).scheme != "ssh" ? 1 : GIT_FETCH_DEPTH_FULL;
         opts.callbacks.payload = &act;
         opts.callbacks.sideband_progress = sidebandProgressCallback;
         opts.callbacks.transfer_progress = transferProgressCallback;