Kotlin: back off from lazy LFS rules

Those have shown to cause problems with too many concurrent downloads.

This changes kotlinc dependencies fetching to:
* use `resource/kotlinc-dependencies` if available (which is the case
  for the internal repo)
* otherwise, download them from maven.

This means sha256 hashes need to be written down for bazel.

Author: redsun82

.gitattributes

@@ -52,7 +52,6 @@
 
 /java/ql/test/stubs/**/*.java linguist-generated=true
 /java/ql/test/experimental/stubs/**/*.java linguist-generated=true
-/java/kotlin-extractor/deps/*.jar filter=lfs diff=lfs merge=lfs -text
 
 # Force git not to modify line endings for go or html files under the go/ql directory
 /go/ql/**/*.go -text

java/kotlin-extractor/deps.bzl

@@ -1,5 +1,4 @@
 load("//java/kotlin-extractor:versions.bzl", "VERSIONS", "version_less")
-load("//misc/bazel:lfs.bzl", "lfs_smudge")
 
 _kotlin_dep_build = """
 load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_import")
@@ -16,9 +15,28 @@ _empty_zip = "PK\005\006\000\000\000\000\000\000\000\000\000\000\000\000\000\000
 def _get_dep(repository_ctx, name):
     return repository_ctx.path(Label("//java/kotlin-extractor/deps:%s" % name))
 
+_local_path = "{root}/resources/kotlin-dependencies/kotlin-{kind}-{version}.jar"
+_maven_url = "https://repo1.maven.org/maven2/org/jetbrains/kotlin/kotlin-{kind}/{version}/kotlin-{kind}-{version}.jar"
+
 def _kotlin_dep_impl(repository_ctx):
     _, _, name = repository_ctx.name.rpartition("~")
-    lfs_smudge(repository_ctx, [_get_dep(repository_ctx, name + ".jar")])
+    kind = repository_ctx.attr.kind
+    version = repository_ctx.attr.version
+    filename = "kotlin-%s-%s.jar" % (kind, version)
+    local_path = _local_path.format(root = repository_ctx.workspace_root, kind = kind, version = version)
+    if repository_ctx.path(local_path).exists:
+        url = "file://%s" % local_path
+    else:
+        url = _maven_url.format(kind = kind, version = version)
+
+    sha256 = VERSIONS[version].get(kind, "")
+    res = repository_ctx.download(url, output = filename, sha256 = sha256)
+    if not sha256:
+        fail('\nPlease add\n  "%s": "%s",\nto VERSIONS["%s"] in java/kotlin-extractor/versions.bzl' % (
+            kind,
+            res.sha256,
+            version,
+        ))
 
     # for some reason rules_kotlin warns about these jars missing, this is to silence those warnings
     repository_ctx.file("empty.zip", _empty_zip)
@@ -34,6 +52,10 @@ def _kotlin_dep_impl(repository_ctx):
 
 _kotlin_dep = repository_rule(
     implementation = _kotlin_dep_impl,
+    attrs = {
+        "kind": attr.string(),
+        "version": attr.string(),
+    },
 )
 
 def _walk(dir):
@@ -121,7 +143,7 @@ _defaults = repository_rule(implementation = _defaults_impl)
 def _kotlin_deps_impl(module_ctx):
     for v in VERSIONS:
         for lib in ("compiler", "compiler-embeddable", "stdlib"):
-            _kotlin_dep(name = "kotlin-%s-%s" % (lib, v))
+            _kotlin_dep(name = "kotlin-%s-%s" % (lib, v), kind = lib, version = v)
     _embeddable_source(name = "codeql_kotlin_embeddable")
     _defaults(name = "codeql_kotlin_defaults")
     return module_ctx.extension_metadata(