internal/scan: change the way convert mode works

This changes convert mode to just modify the source of vulnerabilities
This means it builds the output and handles exit codes like normal.
This fixes the fact that convert does not obey -show flags, or return failure on vulnerabilities.

Change-Id: Ia264d0acbfe49f2ff814be2305e108f144a17d73
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/517156
Run-TryBot: Ian Cottrell <[email protected]>
Reviewed-by: Maceo Thompson <[email protected]>
Reviewed-by: Zvonimir Pavlinovic <[email protected]>
Auto-Submit: Ian Cottrell <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: ianthehat

cmd/govulncheck/testdata/convert_text.ct

@@ -1,6 +1,6 @@
 #####
 # Test using the conversion from json on stdin to text on stdout
-$ govulncheck -mode=convert < convert_input.json
+$ govulncheck -mode=convert < convert_input.json --> FAIL 3
 Scanning your code and P packages across M dependent modules for known vulnerabilities...
 
 Vulnerability #1: GO-2021-0265

internal/scan/run.go

@@ -27,9 +27,6 @@ func RunGovulncheck(ctx context.Context, env []string, r io.Reader, stdout io.Wr
 	if err := parseFlags(cfg, stderr, args); err != nil {
 		return err
 	}
-	if cfg.mode == modeConvert {
-		return convertJSONToText(r, stdout)
-	}
 
 	client, err := client.NewClient(cfg.db, nil)
 	if err != nil {
@@ -60,6 +57,8 @@ func RunGovulncheck(ctx context.Context, env []string, r io.Reader, stdout io.Wr
 		err = runBinary(ctx, handler, cfg, client)
 	case modeQuery:
 		err = runQuery(ctx, handler, cfg, client)
+	case modeConvert:
+		err = govulncheck.HandleJSON(r, handler)
 	}
 	if err != nil {
 		return err
@@ -132,14 +131,3 @@ func scannerVersion(cfg *config, bi *debug.BuildInfo) {
 	}
 	cfg.ScannerVersion = buf.String()
 }
-
-// convertJSONToText converts r, which is expected to be the JSON output of govulncheck,
-// into the text output, and writes the output to w.
-func convertJSONToText(r io.Reader, w io.Writer) error {
-	h := NewTextHandler(w)
-	if err := govulncheck.HandleJSON(r, h); err != nil {
-		return err
-	}
-	Flush(h)
-	return nil
-}