feat: implement merge modes

Author: dominykas

lib/travis/imports.js

@@ -6,8 +6,12 @@ const Yaml = require('js-yaml');
 const Loader = require('../loader');
 const Utils = require('../utils');
 
+const TravisMerge = require('./merge');
 
-const internals = {};
+
+const internals = {
+    validMergeModes: new Set(['deep_merge_append', 'deep_merge_prepend', 'deep_merge', 'merge'])
+};
 
 
 internals.log = Debug('detect-node-support');
@@ -22,6 +26,8 @@ internals.normalizeImports = (travisYaml, { relativeTo }) => {
                 entry = { source: entry };
             }
 
+            const original = entry.source;
+
             if (entry.source.startsWith('./')) {
                 entry.source = entry.source.substring(2);
 
@@ -33,6 +39,14 @@ internals.normalizeImports = (travisYaml, { relativeTo }) => {
                 }
             }
 
+            if (!entry.mode) {
+                entry.mode = 'deep_merge_append';
+            }
+
+            if (!internals.validMergeModes.has(entry.mode)) {
+                throw new Error(`Invalid merge mode for ${original} in ${relativeTo ? relativeTo.source : '.travis.yml'}: ${entry.mode}`);
+            }
+
             return entry;
         })
         .filter((entry) => !entry.if); // @todo: log a warning
@@ -82,13 +96,8 @@ exports.apply = async (yaml, { loadFile, relativeTo, cache = new Map() }) => {
 
         await exports.apply(imported, { loadFile, relativeTo: entry, cache });
 
-        for (const key in imported) {
-
-            if (key === 'import') {
-                continue;
-            }
+        delete imported.import;
 
-            yaml[key] = imported[key];
-        }
+        TravisMerge[entry.mode](yaml, imported);
     }
 };

lib/travis/merge.js

@@ -0,0 +1,65 @@
+'use strict';
+
+// ref: https://github.com/travis-ci/travis-yml/blob/bf82881491134c72a64778f9664a8dd3f97158e7/lib/travis/yml/support/merge.rb
+
+const internals = {};
+
+
+internals.isObject = (arg) => typeof arg === 'object' && !Array.isArray(arg);
+
+
+exports.deep_merge_append = (left, right) => {
+
+    for (const key in right) {
+
+        if (internals.isObject(left[key]) && internals.isObject(right[key])) {
+            exports.deep_merge_append(left[key], right[key]);
+            continue;
+        }
+
+        if (Array.isArray(left[key]) && Array.isArray(right[key])) {
+            left[key].push(...right[key]);
+            continue;
+        }
+
+        left[key] = right[key];
+    }
+};
+
+exports.deep_merge_prepend = (left, right) => {
+
+    for (const key in right) {
+
+        if (internals.isObject(left[key]) && internals.isObject(right[key])) {
+            exports.deep_merge_prepend(left[key], right[key]);
+            continue;
+        }
+
+        if (Array.isArray(left[key]) && Array.isArray(right[key])) {
+            left[key].unshift(...right[key]);
+            continue;
+        }
+
+        left[key] = right[key];
+    }
+};
+
+exports.deep_merge = (left, right) => {
+
+    for (const key in right) {
+
+        if (internals.isObject(left[key]) && internals.isObject(right[key])) {
+            exports.deep_merge(left[key], right[key]);
+            continue;
+        }
+
+        left[key] = right[key];
+    }
+};
+
+exports.merge = (left, right) => {
+
+    for (const key in right) {
+        left[key] = right[key];
+    }
+};

test/fixtures/index.js

@@ -91,6 +91,9 @@ module.exports = class TestContext {
             Fs.mkdirSync(Path.join(this.path, 'partials'));
             const partialYmls = [
                 'indirect-node-14.yml',
+                'merge-invalid.yml',
+                'node-10.yml',
+                'node-12.yml',
                 'node-14.yml'
             ];
             for (const fn of partialYmls) {

test/fixtures/travis-ymls/testing-imports/merge-deep-prepend-append.yml

@@ -0,0 +1,9 @@
+language: node_js
+node_js:
+  - "8"
+import:
+  - source: partials/node-14.yml # default merge: deep_merge_append
+  - source: partials/node-12.yml
+    mode: deep_merge_prepend
+  - source: partials/node-10.yml
+    mode: deep_merge_append

test/fixtures/travis-ymls/testing-imports/merge-deep.yml

@@ -0,0 +1,7 @@
+language: node_js
+node_js:
+  - "8"
+import:
+  - source: partials/node-14.yml # default merge: deep_merge_append
+  - source: partials/node-12.yml
+    mode: deep_merge

test/fixtures/travis-ymls/testing-imports/merge-invalid.yml

@@ -0,0 +1,5 @@
+language: node_js
+node_js:
+  - "8"
+import:
+  - source: partials/merge-invalid.yml

test/fixtures/travis-ymls/testing-imports/merge-shallow.yml

@@ -0,0 +1,7 @@
+language: node_js
+node_js:
+  - "8"
+import:
+  - source: partials/node-14.yml # default merge: deep_merge_append
+  - source: partials/node-12.yml
+    mode: merge

test/fixtures/travis-ymls/testing-imports/partials/merge-invalid.yml

@@ -0,0 +1,7 @@
+language: node_js
+node_js:
+  - "8"
+import:
+  - source: partials/node-14.yml # default merge: deep_merge_append
+  - source: partials/node-12.yml
+    mode: no_such_merge_mode

test/fixtures/travis-ymls/testing-imports/partials/node-10.yml

@@ -0,0 +1,3 @@
+node_js:
+  - "10.15"
+  - "10.16"

test/fixtures/travis-ymls/testing-imports/partials/node-12.yml

@@ -0,0 +1,2 @@
+node_js:
+  - "12"