buildifier: move out of array addition

When mutating arrays the linter prefers to use extend/append instead of
+= to the existing array.

Also moving from arrays to ctx.actions.attr instead of arrays when
passing values into ctx.actions, this reduces the memory preassure during
the bazel analysis phase and delays it until the action graph gets
executed.

internal/bazeldnf.bzl

@@ -8,16 +8,15 @@ def _bazeldnf_impl(ctx):
     out_file = ctx.actions.declare_file(ctx.label.name + ".bash")
     args = []
     if ctx.attr.command:
-        args += [ctx.attr.command]
+        args.append(ctx.attr.command)
     if ctx.attr.rulename:
-        args += ["--name", ctx.attr.rulename]
+        args.extend(["--name", ctx.attr.rulename])
     if ctx.attr.rpmtree:
-        args += ["--rpmtree", ctx.attr.rpmtree]
+        args.extend(["--rpmtree", ctx.attr.rpmtree])
     if ctx.file.tar:
-        args += ["--input", ctx.file.tar.path]
-        transitive_dependencies += [ctx.attr.tar.files]
-    for lib in ctx.attr.libs:
-        args += [lib]
+        args.extend(["--input", ctx.file.tar.path])
+        transitive_dependencies.extend(ctx.attr.tar.files)
+    args.extend(ctx.attr.libs)
 
     toolchain = ctx.toolchains[BAZELDNF_TOOLCHAIN]
 

internal/rpmtree.bzl

@@ -22,55 +22,56 @@ make available to bazel
 load("//bazeldnf:toolchain.bzl", "BAZELDNF_TOOLCHAIN")
 
 def _rpm2tar_impl(ctx):
-    rpms = []
-    for rpm in ctx.files.rpms:
-        rpms += ["--input", rpm.path]
+    args = ctx.actions.args()
 
     out = ctx.outputs.out
-    args = ["rpm2tar", "--output", out.path]
+    args.add_all(["rpm2tar", "--output", out])
 
     if ctx.attr.symlinks:
         symlinks = []
         for k, v in ctx.attr.symlinks.items():
-            symlinks += [k + "=" + v]
-        args += ["--symlinks", ",".join(symlinks)]
+            symlinks.append(k + "=" + v)
+        args.add_joined("--symlinks", symlinks, join_with = ",")
 
     if ctx.attr.capabilities:
         capabilities = []
         for k, v in ctx.attr.capabilities.items():
-            capabilities += [k + "=" + ":".join(v)]
-        args += ["--capabilities", ",".join(capabilities)]
+            capabilities.append(k + "=" + ":".join(v))
+        args.add_joined("--capabilities", capabilities, join_with = ",")
 
     if ctx.attr.selinux_labels:
         selinux_labels = []
         for k, v in ctx.attr.selinux_labels.items():
-            selinux_labels += [k + "=" + v]
-        args += ["--selinux-labels", ",".join(selinux_labels)]
+            selinux_labels.append(k + "=" + v)
+        args.add_joined("--selinux-labels", selinux_labels, join_with = ",")
 
-    args += rpms
+    for rpm in ctx.files.rpms:
+        args.add_all(["--input", rpm.path])
 
     ctx.actions.run(
         inputs = ctx.files.rpms,
         outputs = [out],
-        arguments = args,
+        arguments = [args],
         mnemonic = "Rpm2Tar",
         progress_message = "Converting %s to tar" % ctx.label.name,
         executable = ctx.toolchains[BAZELDNF_TOOLCHAIN]._tool,
     )
 
     return [DefaultInfo(files = depset([ctx.outputs.out]))]
 
+def _expand_path(files):
+    return [x.path for x in files]
+
 def _tar2files_impl(ctx):
-    out = ctx.outputs.out
-    files = []
-    for out in ctx.outputs.out:
-        files += [out.path]
+    args = ctx.actions.args()
+
+    args.add_all(["tar2files", "--file-prefix", ctx.attr.prefix, "--input", ctx.files.tar[0]])
+    args.add_all([ctx.outputs.out], map_each = _expand_path)
 
-    args = ["tar2files", "--file-prefix", ctx.attr.prefix, "--input", ctx.files.tar[0].path] + files
     ctx.actions.run(
         inputs = ctx.files.tar,
         outputs = ctx.outputs.out,
-        arguments = args,
+        arguments = [args],
         mnemonic = "Tar2Files",
         progress_message = "Extracting files",
         executable = ctx.toolchains[BAZELDNF_TOOLCHAIN]._tool,