fix: CI conditions (#91)

* fix: top-level conditional to trigger releases

The condition being only on the stage does not seem to trigger a CI run.

Signed-off-by: Thulio Ferraz Assis <thulio.assis@suse.com>

* fix: free-spacing regex string and condition

The free-spacing modifier does not work with literal '\n' characters. It
turns out that when indenting multiple levels in the string, the
convertion from YAML to string adds the '\n' characters.

Comments in the regex (# comment) also breaks it, matching conditions
that should not be matched.

Tested this approach with the travis-conditions CLI tool.

Also, this commit fixes the top-level condition interaction with the
release stage condition.

Signed-off-by: Thulio Ferraz Assis <thulio.assis@suse.com>

* feat: build on forks and add explanatory comment

Signed-off-by: Thulio Ferraz Assis <thulio.assis@suse.com>

.travis.yml

@@ -4,6 +4,27 @@ go: 1.14.x
 os: linux
 dist: bionic
 
+# Don't indent any line more than one level to avoid '\n' characters in the converter string,
+# which breaks the regex free-spacing modifier. Also, do NOT include comments in the regex string.
+# The logic:
+#   * Build on push to branches on forks that setup Travis - not tied to the
+#     kubernetes-sigs/minibroker Travis account.
+#   * Build on branch master that is not tagged.
+#   * Build on kubernetes-sigs/minibroker when a tag is present and the branch matches a semver
+#     string.
+if: >-
+  (repo != "kubernetes-sigs/minibroker")
+  OR ((branch = master) AND (tag IS NOT present))
+  OR (
+  (repo = "kubernetes-sigs/minibroker")
+  AND (tag IS present)
+  AND (branch ~= /^(?x)
+  v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)
+  (?:-((?:0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*))*))?
+  (?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?
+  $/)
+  )
+
 cache:
   directories:
   - ${HOME}/assets
@@ -60,27 +81,4 @@ stages:
 - test
 - test-integration
 - name: release
-  if: >-
-    (repo = "kubernetes-sigs/minibroker") AND
-    (tag IS present) AND
-    (branch ~= /^(?x)
-        v(0|[1-9][0-9]*)  # major
-        \.
-        (0|[1-9][0-9]*)  # minor
-        \.
-        (0|[1-9][0-9]*)  # patch
-        (?:
-          - # pre-release
-          (
-            (?:0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*)
-            (?:\.
-              (?:0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*)
-            )*
-          )
-        )?
-        # build
-        (?:\+([0-9a-zA-Z-]+
-          (?:\.[0-9a-zA-Z-]+)*
-        )
-      )?
-    $/)
+  if: (repo = "kubernetes-sigs/minibroker") AND (tag IS present) AND (branch != master)