buf: remove reliance of tests on git file transport

A recent git security update disabled the file transport by default,
see https://github.blog/2022-10-18-git-security-vulnerabilities-announced/#cve-2022-39253

We can pick an upstream patch which needed to be rebased unfortunately,
so we can't fetch it directly from GitHub.

pkgs/development/tools/buf/buf-tests-dont-use-file-transport.patch

@@ -0,0 +1,51 @@
+commit e9219b88de5ed37af337ee2d2e71e7ec7c0aad1b
+Author: Robbert van Ginkel <rvanginkel@buf.build>
+Date:   Thu Oct 20 16:43:28 2022 -0400
+
+    Fix git unit test by using fake git server rather than file:// (#1518)
+    
+    More recent versions of git fix a CVE by disabling some usage of the
+    `file://` transport, see
+    https://github.blog/2022-10-18-git-security-vulnerabilities-announced/#cve-2022-39253.
+    We were using this transport in tests.
+    
+    Instead, use https://git-scm.com/docs/git-http-backend to serve up this
+    repository locally so we don't have to use the file protocol. This
+    should be a more accurate tests, since we mostly expect submodules to
+    come from servers.
+
+diff --git a/private/pkg/git/git_test.go b/private/pkg/git/git_test.go
+index 7b77b6cd..7132054e 100644
+--- a/private/pkg/git/git_test.go
++++ b/private/pkg/git/git_test.go
+@@ -17,6 +17,8 @@ package git
+ import (
+ 	"context"
+ 	"errors"
++	"net/http/cgi"
++	"net/http/httptest"
+ 	"os"
+ 	"os/exec"
+ 	"path/filepath"
+@@ -213,6 +215,21 @@ func createGitDirs(
+ 	runCommand(ctx, t, container, runner, "git", "-C", submodulePath, "add", "test.proto")
+ 	runCommand(ctx, t, container, runner, "git", "-C", submodulePath, "commit", "-m", "commit 0")
+ 
++	gitExecPath, err := command.RunStdout(ctx, container, runner, "git", "--exec-path")
++	require.NoError(t, err)
++	t.Log(filepath.Join(string(gitExecPath), "git-http-backend"))
++	// https://git-scm.com/docs/git-http-backend#_description
++	f, err := os.Create(filepath.Join(submodulePath, ".git", "git-daemon-export-ok"))
++	require.NoError(t, err)
++	require.NoError(t, f.Close())
++	server := httptest.NewServer(&cgi.Handler{
++		Path: filepath.Join(strings.TrimSpace(string(gitExecPath)), "git-http-backend"),
++		Dir:  submodulePath,
++		Env:  []string{"GIT_PROJECT_ROOT=" + submodulePath},
++	})
++	t.Cleanup(server.Close)
++	submodulePath = server.URL
++
+ 	originPath := filepath.Join(tmpDir, "origin")
+ 	require.NoError(t, os.MkdirAll(originPath, 0777))
+ 	runCommand(ctx, t, container, runner, "git", "-C", originPath, "init")

pkgs/development/tools/buf/default.nix

@@ -26,6 +26,9 @@ buildGoModule rec {
     ./skip_test_requiring_network.patch
     # Skip TestWorkspaceGit which requires .git and commits.
     ./skip_test_requiring_dotgit.patch
+    # Remove reliance of tests on file protocol which is disabled in git by default now
+    # Rebased upstream change https://github.com/bufbuild/buf/commit/bcaa77f8bbb8f6c198154c7c8d53596da4506dab
+    ./buf-tests-dont-use-file-transport.patch
   ];
 
   nativeBuildInputs = [ installShellFiles ];