gopls/internal/migrate.sh: a script to migrate internal/lsp to gopls/

Add a script that does the migration of the internal/lsp directory to
gopls/internal/lsp. This is done in a separate CL so that in-progress
CLs can rebase on top of *this CL*, run this script, and then rebase to
tip.

For golang/go#54509

Change-Id: I6f529c1e4ba29b4d88dc26278d54a055f1ef212e
Reviewed-on: https://go-review.googlesource.com/c/tools/+/426795
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>

gopls/internal/migrate.sh

@@ -0,0 +1,68 @@
+#!/bin/bash
+#
+# Copyright 2022 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+#
+# Migrates the internal/lsp directory to gopls/internal/lsp. Run this script
+# from the root of x/tools to migrate in-progress CLs.
+#
+# See golang/go#54509 for more details. This script may be deleted once a
+# reasonable amount of time has passed such that all active in-progress CLs
+# have been rebased.
+
+set -eu
+
+# A portable -i flag. Darwin requires two parameters.
+# See https://stackoverflow.com/questions/5694228/sed-in-place-flag-that-works-both-on-mac-bsd-and-linux
+# for more details.
+sedi=(-i)
+case "$(uname)" in
+  Darwin*) sedi=(-i "")
+esac
+
+# mvpath moves the directory at the relative path $1 to the relative path $2,
+# moving files and rewriting import paths.
+#
+# It uses heuristics to identify import path literals, and therefore may be
+# imprecise.
+function mvpath() {
+  # If the source also doesn't exist, it may have already been moved.
+  # Skip so that this script is idempotent.
+  if [[ ! -d $1 ]]; then
+    echo "WARNING: skipping nonexistent source directory $1"
+    return 0
+  fi
+
+  # git can sometimes leave behind empty directories, which can change the
+  # behavior of the mv command below.
+  if [[ -d $2 ]] || [[ -f $2 ]]; then
+    echo "ERROR: destination $2 already exists"
+    exit 1
+  fi
+
+  mv $1 $2
+
+  local old="golang.org/x/tools/$1"
+  local new="golang.org/x/tools/$2"
+
+  # Replace instances of the old import path with the new. This is imprecise,
+  # but we are a bit careful to avoid replacing golang.org/x/tools/foox with
+  # golang.org/x/tools/barx when moving foo->bar: the occurrence of the import
+  # path must be followed by whitespace, /, or a closing " or `.
+  local replace="s:${old}\([[:space:]/\"\`]\):${new}\1:g"
+  find . -type f \( \
+    -name ".git" -prune -o \
+    -name "*.go" -o \
+    -name "*.in" -o \
+    -name "*.golden" -o \
+    -name "*.hlp" -o \
+    -name "*.md" \) \
+    -exec sed "${sedi[@]}" -e $replace {} \;
+}
+
+mvpath internal/lsp/diff internal/diff
+mvpath internal/lsp/fuzzy internal/fuzzy
+mvpath internal/lsp/debug/tag internal/event/tag
+mvpath internal/lsp/bug internal/bug
+mvpath internal/lsp gopls/internal/lsp