Add tools/sync-bazelversion.sh, commit results (#1629)

* Add tools/sync-bazelversion.sh, commit results

Ensures Bazelisk uses the same Bazel version in every workspace in the
project. Part of #1482.

I discovered that the workspaces under the main workspace were running
the latest mainline Blaze release I had installed, instead of 6.5.0 from
`.bazelversion`. Now all the workspaces are synchronized on the same
Bazel version.

As noted in the `tools/sync-bazelversion.sh` comments, symlinks or an
`import ../.bazelversion` mechanism would be preferable. However, the
former can surprise Windows users, and Bazelisk doesn't support the
latter.

* Move sync-bazelversion.sh from tools/ to scripts/

Requested by @simuons in #1629.

Author: mbland

dt_patches/test_dt_patches/.bazelversion

@@ -1 +1 @@
-5.3.1
+6.5.0

dt_patches/test_dt_patches_user_srcjar/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/crossbuild/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/scala3/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/semanticdb/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/testing/multi_frameworks_toolchain/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/testing/scalatest_repositories/.bazelversion

@@ -0,0 +1 @@
+6.5.0

examples/testing/specs2_junit_repositories/.bazelversion

@@ -0,0 +1 @@
+6.5.0

scripts/sync-bazelversion.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+#
+# Synchronizes .bazelversion in nested workspaces with the top level workspace.
+#
+# These could be symlinks, but that might break Windows users who don't know how
+# to enable symlinks. Of course, they're programmers, they should learn, but
+# avoiding surprises as a general principle is best.
+#
+# What would be ideal is the `import ../.bazelrc` syntax supported by Bazel, but
+# Bazelisk doesn't currently support that.
+
+ROOTDIR="${BASH_SOURCE[0]%/*}/.."
+cd "$ROOTDIR"
+
+if [[ "$?" -ne 0 ]]; then
+  echo "Could not change to $ROOTDIR." >&2
+  exit 1
+elif [[ ! -r .bazelversion ]]; then
+  echo ".bazelversion doesn't exist or isn't readable in $PWD." >&2
+  exit 1
+fi
+
+while IFS="" read repo_marker_path; do
+  repo_path="${repo_marker_path%/*}"
+
+  # We search for WORKSPACE and MODULE.bazel instead of .bazelversion in case
+  # anyone adds new child repositories. But we need to guard against overwriting
+  # the top-level WORKSPACE and MODULE.bazel files.
+  if [[ "$repo_path" != "$repo_marker_path" ]]; then
+    cp .bazelversion "$repo_path"
+  fi
+done < <(find [A-Za-z0-9]* \( -name "WORKSPACE*" -or -name "MODULE.bazel" \))

test_cross_build/.bazelversion

@@ -0,0 +1 @@
+6.5.0