internal/getproviders: PackageFilePathForPackage

This is the equivalent of UnpackedDirectoryPathForPackage when working
with the packed directory layout. It returns a path to a .zip file with
a name that would be detected by SearchLocalDirectory as a
PackageLocalArchive package.

internal/getproviders/filesystem_search.go

@@ -243,3 +243,16 @@ func UnpackedDirectoryPathForPackage(baseDir string, provider addrs.Provider, ve
 		platform.String(),
 	))
 }
+
+// PackedFilePathForPackage is similar to
+// PackageMeta.PackedFilePath but makes its decision based on
+// individually-passed provider address, version, and target platform so that
+// it can be used by callers outside this package that may have other
+// types that represent package identifiers.
+func PackedFilePathForPackage(baseDir string, provider addrs.Provider, version Version, platform Platform) string {
+	return filepath.ToSlash(filepath.Join(
+		baseDir,
+		provider.Hostname.ForDisplay(), provider.Namespace, provider.Type,
+		fmt.Sprintf("terraform-provider-%s_%s_%s.zip", provider.Type, version.String(), platform.String()),
+	))
+}

internal/getproviders/types.go

@@ -230,6 +230,17 @@ func (m PackageMeta) UnpackedDirectoryPath(baseDir string) string {
 	return UnpackedDirectoryPathForPackage(baseDir, m.Provider, m.Version, m.TargetPlatform)
 }
 
+// PackedFilePath determines the path under the given base
+// directory where SearchLocalDirectory or the FilesystemMirrorSource would
+// expect to find packed copy (a .zip archive) of the receiving PackageMeta.
+//
+// The result always uses forward slashes as path separator, even on Windows,
+// to produce a consistent result on all platforms. Windows accepts both
+// direction of slash as long as each individual path string is self-consistent.
+func (m PackageMeta) PackedFilePath(baseDir string) string {
+	return PackedFilePathForPackage(baseDir, m.Provider, m.Version, m.TargetPlatform)
+}
+
 // PackageLocation represents a location where a provider distribution package
 // can be obtained. A value of this type contains one of the following
 // concrete types: PackageLocalArchive, PackageLocalDir, or PackageHTTPURL.