Handle exercise directories with numeric suffixes

An early design decision was to allow people to work on multiple solutions to the same
exercise at the same time. We later decided not to do this, but the CLI still had
logic that supported it.

This caused us to (incorrectly) create exercise directories that were named with a
numeric suffix, which would then get submitted to the backend server, which doesn't
care about filepaths.

Because the exercise with the numeric suffix doesn't match the expected path, we did
not correctly trim off any leading directories on submit, which further caused
the download command to put the solution in a weirdly and deeply nested directory,
making the solution hard to find and review.

Author: Katrina Owen

cmd/download.go

@@ -9,6 +9,7 @@ import (
 	netURL "net/url"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/exercism/cli/api"
@@ -200,6 +201,15 @@ func runDownload(cfg config.Config, flags *pflag.FlagSet, args []string) error {
 		// TODO: if there's a collision, interactively resolve (show diff, ask if overwrite).
 		// TODO: handle --force flag to overwrite without asking.
 
+		// Work around a path bug due to an early design decision (later reversed) to
+		// allow numeric suffixes for exercise directories, allowing people to have
+		// multiple parallel versions of an exercise.
+		pattern := fmt.Sprintf(`\A.*[/\\]%s-\d*/`, solution.Exercise)
+		rgxNumericSuffix := regexp.MustCompile(pattern)
+		if rgxNumericSuffix.MatchString(file) {
+			file = string(rgxNumericSuffix.ReplaceAll([]byte(file), []byte("")))
+		}
+
 		// Rewrite paths submitted with an older, buggy client where the Windows path is being treated as part of the filename.
 		file = strings.Replace(file, "\\", "/", -1)
 

cmd/download_test.go

@@ -166,6 +166,10 @@ func fakeDownloadServer(requestor, teamSlug string) *httptest.Server {
 		fmt.Fprint(w, "this is file 2")
 	})
 
+	mux.HandleFunc("/full/path/with/numeric-suffix/bogus-track/bogus-exercise-12345/subdir/numeric.txt", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, "with numeric suffix")
+	})
+
 	mux.HandleFunc("/special-char-filename#.txt", func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprint(w, "this is a special file")
 	})
@@ -217,6 +221,11 @@ func assertDownloadedCorrectFiles(t *testing.T, targetDir string) {
 			path:     filepath.Join(targetDir, "bogus-track", "bogus-exercise", "subdir", "file-2.txt"),
 			contents: "this is file 2",
 		},
+		{
+			desc:     "a path with a numeric suffix",
+			path:     filepath.Join(targetDir, "bogus-track", "bogus-exercise", "subdir", "numeric.txt"),
+			contents: "with numeric suffix",
+		},
 		{
 			desc:     "a file that requires URL encoding",
 			path:     filepath.Join(targetDir, "bogus-track", "bogus-exercise", "special-char-filename#.txt"),
@@ -278,7 +287,8 @@ const payloadTemplate = `
 			"/with-leading-slash.txt",
 			"\\with-leading-backslash.txt",
 			"\\with\\backslashes\\in\\path.txt",
-			"file-3.txt"
+			"file-3.txt",
+			"/full/path/with/numeric-suffix/bogus-track/bogus-exercise-12345/subdir/numeric.txt"
 		],
 		"iteration": {
 			"submitted_at": "2017-08-21t10:11:12.130z"