From f1e46c3f142c0665f90119996f0ebb8048dfb0c7 Mon Sep 17 00:00:00 2001
From: Matt Clarkson <matthew.clarkson@arm.com>
Date: Mon, 28 Oct 2024 12:46:49 +0000
Subject: [PATCH] fix: detect both `WORKSPACE` and `REPO.bazel` in repositories

When a repository label is passed, we validate that it **is**
a repository by checking for `REPO.bazel`.

To support back to `7.0.0` we can check for both `WORKSPACE` _and_ `REPO.bazel`.
---
 MODULE.bazel                            |  2 +-
 toolchain/export/symlink/repository.bzl | 12 ++++++------
 toolchain/local/select/repository.bzl   | 13 ++++++-------
 toolchain/repository/BUILD.bazel        |  0
 toolchain/repository/root.bzl           | 14 ++++++++++++++
 5 files changed, 27 insertions(+), 14 deletions(-)
 create mode 100644 toolchain/repository/BUILD.bazel
 create mode 100644 toolchain/repository/root.bzl

diff --git a/MODULE.bazel b/MODULE.bazel
index 843dd77..ddfaaaa 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -2,7 +2,7 @@ module(
     name = "toolchain_utils",
     version = "0.0.0",
     bazel_compatibility = [
-        ">=7.1.0",
+        ">=7.0.0",
     ],
 )
 
diff --git a/toolchain/export/symlink/repository.bzl b/toolchain/export/symlink/repository.bzl
index 672e4ea..a9dcbc9 100644
--- a/toolchain/export/symlink/repository.bzl
+++ b/toolchain/export/symlink/repository.bzl
@@ -1,3 +1,5 @@
+load("//toolchain/repository:root.bzl", "root")
+
 visibility("//toolchain/export/...")
 
 DOC = "Symlinks a repository to another."
@@ -11,13 +13,11 @@ ATTRS = {
 
 def implementation(rctx):
     label = rctx.attr.target
-    workspace = label.relative(":REPO.bazel")
-    path = rctx.path(workspace)
-    if not path.exists:
-        fail("Failed to find `{}`, can only symlink repository labels.".format(path, label))
-    target = path.dirname
+    path = root(rctx, label)
+    if not path:
+        fail("Can only symlink repository labels.".format(label))
     rctx.delete(".")
-    rctx.symlink(target, ".")
+    rctx.symlink(path, ".")
 
 symlink = repository_rule(
     doc = DOC,
diff --git a/toolchain/local/select/repository.bzl b/toolchain/local/select/repository.bzl
index 4597e5c..57258bb 100644
--- a/toolchain/local/select/repository.bzl
+++ b/toolchain/local/select/repository.bzl
@@ -1,3 +1,4 @@
+load("//toolchain/repository:root.bzl", "root")
 load("//toolchain:separator.bzl", "SEPARATOR")
 load(":resolve.bzl", resolve = "key")
 
@@ -34,19 +35,17 @@ toolchian_local_select(
 
 def canonical(rctx, label):
     prefix = SEPARATOR.join(rctx.name.split(SEPARATOR)[:-1])
-    return "@@{}{}{}".format(prefix, SEPARATOR, label.removeprefix("@"))
+    return Label("@@{}{}{}".format(prefix, SEPARATOR, label.removeprefix("@")))
 
 def implementation(rctx):
     label = resolve(rctx.attr.map, no_match_error = rctx.attr.no_match_error)
     canon = canonical(rctx, label)
-    workspace = Label("{}//:REPO.bazel".format(canon))
-    path = rctx.path(workspace)
-
-    if not path.exists:
-        fail("Missing `{}` for `{}`: {}".format(canon, rctx.name, path))
+    path = root(rctx, canon)
+    if not path:
+        fail("Missing `{}` for `{}`".format(canon, rctx.name))
 
     rctx.delete(".")
-    rctx.symlink(path.dirname, ".")
+    rctx.symlink(path, ".")
 
 select = repository_rule(
     doc = DOC,
diff --git a/toolchain/repository/BUILD.bazel b/toolchain/repository/BUILD.bazel
new file mode 100644
index 0000000..e69de29
diff --git a/toolchain/repository/root.bzl b/toolchain/repository/root.bzl
new file mode 100644
index 0000000..b3a0b4a
--- /dev/null
+++ b/toolchain/repository/root.bzl
@@ -0,0 +1,14 @@
+visibility("//...")
+
+def root(rctx, label):
+    workspace = label.relative("WORKSPACE")
+    path = rctx.path(workspace)
+    if path.exists:
+        return path.dirname
+
+    repo = label.relative("REPO.bazel")
+    path = rctx.path(repo)
+    if path.exists:
+        return path.dirname
+
+    return None
-- 
GitLab