Add comment as to why we need to dlopen libsvnclient.

1 files changed, 10 insertions, 0 deletions

diff --git a/main/src/addins/VersionControl/MonoDevelop.VersionControl.Subversion.Unix/MonoDevelop.VersionControl.Subversion.Unix/LibSvnClient.cs b/main/src/addins/VersionControl/MonoDevelop.VersionControl.Subversion.Unix/MonoDevelop.VersionControl.Subversion.Unix/LibSvnClient.cs
index 85a76b285c..b976b4e88a 100644
--- a/main/src/addins/VersionControl/MonoDevelop.VersionControl.Subversion.Unix/MonoDevelop.VersionControl.Subversion.Unix/LibSvnClient.cs
+++ b/main/src/addins/VersionControl/MonoDevelop.VersionControl.Subversion.Unix/MonoDevelop.VersionControl.Subversion.Unix/LibSvnClient.cs
@@ -23,6 +23,16 @@ namespace MonoDevelop.VersionControl.Subversion.Unix {
 
 		public static LibSvnClient GetLib ()
 		{
+			// Here be linker dragons.
+			// Due to the way the mono dlloader works, and how svn is architected we need to manually load libsvn_client
+			// Because libsvn_client relies on apr_initialize being called, we need to get the right apr dependency.
+			// Letting mono resolve both libraries separately will only load libsvn_client's deps when needed,
+			// Thus it'll end up loading the wrong libapr in the case of Mac.
+			// We rely on using Xcode's libsvn_client, so if that isn't found or the license hasn't been accepted,
+			// it'll be skipped. If svn is installed from somewhere else (most commonly via brew), we end up loading
+			// brew's libsvn_client and the system libapr, which are mismatched on dependency versions causing a native
+			// crash. dlopen-ining libsvn_client allows us to handle the right mix-match of svn and apr, since it loads
+			// apr via the linker flags on the binary.
 			if (Core.Platform.IsMac) {
 				dlopen ("libsvn_client-1.0.dylib", 0x1);
 				return new LibSvnClient2 ();