4 files changed, 8 insertions, 4 deletions

diff --git a/src/luarocks/fs/lua.lua b/src/luarocks/fs/lua.lua
index 5f7d6c37..94095004 100644
--- a/src/luarocks/fs/lua.lua
+++ b/src/luarocks/fs/lua.lua
@@ -652,7 +652,7 @@ if md5_ok then
 function get_md5(file)
    file = fs.absolute_name(file)
    local file = io.open(file, "rb")
-   if not file then return nil, "Failed to compute MD5 hash for file "..file end
+   if not file then return nil, "Failed to open file for reading: "..file end
    local computed = md5.sumhexa(file:read("*a"))
    file:close()
    if computed then return computed end
diff --git a/src/luarocks/fs/unix/tools.lua b/src/luarocks/fs/unix/tools.lua
index c857b093..5495760b 100644
--- a/src/luarocks/fs/unix/tools.lua
+++ b/src/luarocks/fs/unix/tools.lua
@@ -324,7 +324,7 @@ local md5_cmd = {
 -- @return string: The MD5 checksum
 function get_md5(file)
    local cmd = md5_cmd[cfg.md5checker]
-   if not cmd then return nil end
+   if not cmd then return nil, "no MD5 checker command configured" end
    local pipe = io.popen(cmd.." "..fs.absolute_name(file))
    local computed = pipe:read("*a")
    pipe:close()
diff --git a/src/luarocks/fs/win32/tools.lua b/src/luarocks/fs/win32/tools.lua
index 0ec46314..345ec682 100644
--- a/src/luarocks/fs/win32/tools.lua
+++ b/src/luarocks/fs/win32/tools.lua
@@ -344,7 +344,7 @@ local md5_cmd = {
 -- @return string: The MD5 checksum or nil + message
 function get_md5(file)
    local cmd = md5_cmd[cfg.md5checker]
-   if not cmd then return nil end
+   if not cmd then return nil, "no MD5 checker command configured" end
    local pipe = io.popen(cmd.." "..fs.Q(fs.absolute_name(file)))
    local computed = pipe:read("*a")
    pipe:close()
diff --git a/src/luarocks/manif.lua b/src/luarocks/manif.lua
index 1c7707a9..238c4056 100644
--- a/src/luarocks/manif.lua
+++ b/src/luarocks/manif.lua
@@ -73,7 +73,11 @@ function make_rock_manifest(name, version)
          walk = next
       end
       if fs.is_file(full_path) then
-         last[last_name] = fs.get_md5(full_path)
+         local sum, err = fs.get_md5(full_path)
+         if not sum then
+            return nil, "Failed producing checksum: "..tostring(err)
+         end
+         last[last_name] = sum
       end
    end
    local rock_manifest = { rock_manifest=tree }