cmd/go: make paths consistent between 'go work init' and 'go work use'

Fixes #51448

Change-Id: I86719b55037c377eb82154e169d8a9bbae20b77c
Reviewed-on: https://go-review.googlesource.com/c/go/+/389854
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

src/cmd/go/internal/modload/modfile.go

@@ -802,7 +802,7 @@ var latestVersionIgnoringRetractionsCache par.Cache // path → queryLatestVersi
 // an absolute path or a relative path starting with a '.' or '..'
 // path component.
 func ToDirectoryPath(path string) string {
-	if modfile.IsDirectoryPath(path) {
+	if path == "." || modfile.IsDirectoryPath(path) {
 		return path
 	}
 	// The path is not a relative path or an absolute path, so make it relative

src/cmd/go/internal/workcmd/use.go

@@ -186,5 +186,5 @@ func pathRel(workDir, dir string) (abs, canonical string) {
 
 	// Normalize relative paths to use slashes, so that checked-in go.work
 	// files with relative paths within the repo are platform-independent.
-	return abs, filepath.ToSlash(rel)
+	return abs, modload.ToDirectoryPath(rel)
 }

src/cmd/go/testdata/script/work_init_path.txt

@@ -0,0 +1,17 @@
+# Regression test for https://go.dev/issue/51448.
+# 'go work init . foo/bar' should produce a go.work file
+# with the same paths as 'go work init; go work use -r .'.
+
+go work init . foo/bar
+mv go.work go.work.init
+
+go work init
+go work use -r .
+cmp go.work go.work.init
+
+-- go.mod --
+module example
+go 1.18
+-- foo/bar/go.mod --
+module example
+go 1.18

src/cmd/go/testdata/script/work_use.txt

@@ -14,16 +14,16 @@ use (
 go 1.18
 
 use (
-	foo
-	foo/bar/baz
+	./foo
+	./foo/bar/baz
 )
 -- go.want_work_other --
 go 1.18
 
 use (
-	foo
-	foo/bar/baz
-	other
+	./foo
+	./foo/bar/baz
+	./other
 )
 -- foo/go.mod --
 module foo

src/cmd/go/testdata/script/work_use_deleted.txt

@@ -6,13 +6,13 @@ go 1.18
 
 use (
 	.
-	sub
-	sub/dir/deleted
+	./sub
+	./sub/dir/deleted
 )
 -- go.work.want --
 go 1.18
 
-use sub/dir
+use ./sub/dir
 -- sub/README.txt --
 A go.mod file has been deleted from this directory.
 In addition, the entire subdirectory sub/dir/deleted

src/cmd/go/testdata/script/work_use_dot.txt

@@ -31,7 +31,7 @@ grep '^use ["]?'$PWD'["]?$' ../../go.work
 # resulting workspace would contain a duplicate module.
 cp ../../go.work.orig ../../go.work
 ! go work use $PWD .
-stderr '^go: already added "bar/baz" as "'$PWD'"$'
+stderr '^go: already added "\./bar/baz" as "'$PWD'"$'
 cmp ../../go.work ../../go.work.orig
 
 
@@ -43,7 +43,7 @@ go 1.18
 -- go.work.rel --
 go 1.18
 
-use bar/baz
+use ./bar/baz
 -- bar/baz/go.mod --
 module example/bar/baz
 go 1.18