Fix #21 Use non-zero ranges for diagnostics

If a FROM's base image's digest string is the empty string, the
generated diagnostic's range has a length of zero. This causes the
CLI to not highlight anything in its output. Use the entire
argument's range for the diagnostic instead so that the CLI can at
least highlight something meaningful.

Signed-off-by: Remy Suen <remy.suen@gmail.com>

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## [Unreleased]
+### Fixed
+- use a non-zero range for the diagnostic if FROM's base image's digest is the empty string ([#21](https://github.com/rcjsuen/dockerfile-utils/issues/21))
+
 ## [0.0.6] - 2018-02-11
 ### Added
 - create a Docker image for running the CLI ([#10](https://github.com/rcjsuen/dockerfile-utils/issues/10))
@@ -41,6 +45,7 @@ All notable changes to this project will be documented in this file.
 - create formatter for Dockerfiles
 - create linter for Dockerfiles
 
+[Unreleased]: https://github.com/rcjsuen/dockerfile-utils/compare/v0.0.6...HEAD
 [0.0.6]: https://github.com/rcjsuen/dockerfile-utils/compare/v0.0.5...v0.0.6
 [0.0.5]: https://github.com/rcjsuen/dockerfile-utils/compare/v0.0.4...v0.0.5
 [0.0.4]: https://github.com/rcjsuen/dockerfile-utils/compare/v0.0.3...v0.0.4

src/dockerValidator.ts

@@ -348,6 +348,11 @@ export class Validator {
                                 }
                                 let endIndex = argument.indexOf(':');
                                 if (endIndex === -1) {
+                                    let digest = argument.substring(index + 1);
+                                    if (digest === "") {
+                                        // no digest specified, just highlight the whole argument
+                                        return Validator.createInvalidReferenceFormat(range);
+                                    }
                                     return Validator.createInvalidReferenceFormat(from.getImageDigestRange());
                                 }
                                 let algorithmRegexp = new RegExp(/[A-Fa-f0-9_+.-]+/);

test/dockerValidator.test.ts

@@ -2224,7 +2224,11 @@ describe("Docker Validator Tests", function() {
             });
 
             it("invalid reference format (digest)", function() {
-                let diagnostics = validateDockerfile("FROM alpine@sha25");
+                let diagnostics = validateDockerfile("FROM alpine@");
+                assert.equal(diagnostics.length, 1);
+                assertInvalidReferenceFormat(diagnostics[0], 0, 5, 0, 12);
+
+                diagnostics = validateDockerfile("FROM alpine@sha25");
                 assert.equal(diagnostics.length, 1);
                 assertInvalidReferenceFormat(diagnostics[0], 0, 12, 0, 17);