Blacklist system git2 modules while running tests

In order to run the tests safely, particularly if
the git2 C module isn't built due to a missing dep
we need to blacklist any system git2 module.  This
change also requires lua5.2 for the test suite.

3 files changed, 40 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index fe1db2c..506593c 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ all: test
 
 MODULES := gall gall.util gall.ll \
 	   gall.repository gall.object gall.commit gall.tag gall.tree
-LUA_VER := 5.1
+LUA_VER := 5.2
 
 PREFIX ?= /usr/local
 
@@ -35,7 +35,7 @@ install: cmodule
 	fi
 
 
-LUA := LUA_CPATH="$(shell pwd)/lib/?.so;;" LUA_PATH="$(shell pwd)/lib/?.lua;$(shell pwd)/extras/luacov/src/?.lua;;" lua$(LUA_VER)
+LUA := LUA_CPATH="$(shell pwd)/lib/?.so;;" LUA_PATH="$(shell pwd)/lib/?.lua;$(shell pwd)/extras/luacov/src/?.lua;;" __GALL_LL_GIT2_BLACKLIST="$(shell lua$(LUA_VER) find-git2)" lua$(LUA_VER) -e "dofile('blacklist-system-git2')"
 
 cmodule: try-cmodule
 
diff --git a/blacklist-system-git2 b/blacklist-system-git2
new file mode 100644
index 0000000..92d266c
--- /dev/null
+++ b/blacklist-system-git2
@@ -0,0 +1,21 @@
+-- -*- Lua -*-
+
+-- Our purpose is to blacklist the git2 module(s) found on the package
+-- search path.  We do that by loading an environment variable and then
+-- wrappering the third searcher as necessary.
+
+function __gall_ll_git2_blacklister(f, ignoreme)
+   local type = type
+   local function replacement(modname)
+      local fret, fname = f(modname)
+      if type(fret) == "function" and fname == ignoreme then
+	 return nil, "Blacklisted " .. fname .. "\n"
+      end
+      return fret, fname
+   end
+   return replacement
+end
+
+for fname in (os.getenv("__GALL_LL_GIT2_BLACKLIST") or ""):gmatch("([^:]+)") do
+   package.searchers[3] = __gall_ll_git2_blacklister(package.searchers[3], fname)
+end
diff --git a/find-git2 b/find-git2
new file mode 100644
index 0000000..6bdca05
--- /dev/null
+++ b/find-git2
@@ -0,0 +1,17 @@
+-- -*- Lua -*-
+
+-- Our goal is to find git2.so so we can blacklist it for the duration of
+-- tests.  This is done by essentially rummaging in the package loaders...
+
+dofile("blacklist-system-git2")
+
+local ffunc, loc = package.searchers[3]('gall.ll.git2')
+
+local locs = {}
+while ffunc ~= nil do
+   locs[#locs+1] = loc
+   package.searchers[3] = __gall_ll_git2_blacklister(package.searchers[3], loc)
+   ffunc, loc = package.searchers[3]('gall.ll.git2')
+end
+
+print(table.concat(locs, ":"))