Check that rockspec format is at least 3.0 before fetching submodules

For utility, add deps.format_is_at_least(rockspec, version) function.

2 files changed, 19 insertions, 7 deletions

diff --git a/src/luarocks/deps.lua b/src/luarocks/deps.lua
index 0e3265b5..f6c86d1c 100644
--- a/src/luarocks/deps.lua
+++ b/src/luarocks/deps.lua
@@ -159,6 +159,15 @@ function deps.compare_versions(a, b)
    return deps.parse_version(a) > deps.parse_version(b)
 end
 
+--- Check if rockspec format version satisfies version requirement.
+-- @param rockspec table: The rockspec table.
+-- @param version string: required version.
+-- @return boolean: true if rockspec format matches version or is newer, false otherwise.
+function deps.format_is_at_least(rockspec, version)
+   local rockspec_format = rockspec.rockspec_format or "1.0"
+   return deps.parse_version(rockspec_format) >= deps.parse_version(version)
+end
+
 --- Consumes a constraint from a string, converting it to table format.
 -- For example, a string ">= 1.0, > 2.0" is converted to a table in the
 -- format {op = ">=", version={1,0}} and the rest, "> 2.0", is returned
diff --git a/src/luarocks/fetch/git.lua b/src/luarocks/fetch/git.lua
index 0847f735..ce41659b 100644
--- a/src/luarocks/fetch/git.lua
+++ b/src/luarocks/fetch/git.lua
@@ -110,15 +110,18 @@ function git.get_sources(rockspec, extract, dest_dir, depth)
       end
    end
 
-   command = {fs.Q(git_cmd), "submodule", "update", "--init", "--recursive"}
+   -- Fetching git submodules is supported only when rockspec format is >= 3.0.
+   if deps.format_is_at_least(rockspec, "3.0") then
+      command = {fs.Q(git_cmd), "submodule", "update", "--init", "--recursive"}
 
-   if git_supports_shallow_submodules(git_cmd) then
-      -- Fetch only the last commit of each submodule.
-      table.insert(command, 5, "--depth=1")
-   end
+      if git_supports_shallow_submodules(git_cmd) then
+         -- Fetch only the last commit of each submodule.
+         table.insert(command, 5, "--depth=1")
+      end
 
-   if not fs.execute(unpack(command)) then
-      return nil, 'Failed to fetch submodules.'
+      if not fs.execute(unpack(command)) then
+         return nil, 'Failed to fetch submodules.'
+      end
    end
 
    fs.delete(dir.path(store_dir, module, ".git"))