Exit in error if VCS cannot be forced

Author: hakre

Makefile

@@ -1,11 +1,17 @@
 OPTS ?= ""
 PHP = php
 
-all: test md no-links only-dev only-prod json json-pretty
+all: test test-help test-help-vcs-error md no-links only-dev only-prod json json-pretty
 
 test:
 	$(PHP) ./composer-lock-diff --from test-data/composer.from.lock --to test-data/composer.to.lock $(OPTS)
 
+test-help:
+	$(PHP) ./composer-lock-diff --help
+
+test-help-vcs-error:
+	$(PHP) ./composer-lock-diff --vcs UNKNOWN ; test $$? -eq 1
+
 md:
 	$(MAKE) test OPTS=--md
 

composer-lock-diff

@@ -444,8 +444,8 @@ function parseOpts() {
 
     $vcs = array_key_exists('vcs', $given) ? $given['vcs'] : '';
     if ($vcs && !function_exists('vcsLoad' . ucfirst($vcs))) {
-        error_log("Unsupported vcs '$vcs'\n");
-        usage();
+        error_log(sprintf("Unsupported VCS '$vcs'; supported are: '%s'\n", implode("', '", getVcses())));
+        usage(1);
     }
 
     return array(
@@ -462,9 +462,9 @@ function parseOpts() {
     );
 }
 
-function usage() {
+function usage($status = 0) {
     $vcses = implode(', ', getVcses());
-    print <<<EOF
+    $help = <<<EOF
 Usage: composer-lock-diff [options]
 
 Options:
@@ -480,11 +480,16 @@ Options:
   --no-links   Don't include Compare links in plain text or any links in markdown
   --only-prod  Only include changes from `packages`
   --only-dev   Only include changes from `packages-dev`
-  --vcs        Force vcs ($vcses). Default: attempt to auto-detect
-
+  --vcs        Force VCS ($vcses). Default: attempt to auto-detect
 EOF;
 
-    exit(0);
+    if ($status) {
+        error_log($help);
+    } else {
+        echo $help, "\n";
+    }
+
+    exit($status);
 }
 # vim: ff=unix ts=4 ss=4 sr et