Remove diff from cli-kit/app

.changeset/remove-diff-dependency-inline-lcs.md

@@ -0,0 +1,6 @@
+---
+'@shopify/app': patch
+'@shopify/cli-kit': patch
+---
+
+Remove the `diff` dependency; inline an LCS-based line-diff helper for `app env pull`.

packages/app/package.json

@@ -70,7 +70,6 @@
     "@shopify/theme-check-node": "3.25.0",
     "@shopify/toml-patch": "0.3.0",
     "chokidar": "3.6.0",
-    "diff": "5.2.2",
     "esbuild": "0.28.0",
     "graphql-request": "6.1.0",
     "h3": "1.15.9",
@@ -85,7 +84,6 @@
     "ws": "8.18.0"
   },
   "devDependencies": {
-    "@types/diff": "^5.0.3",
     "@types/proper-lockfile": "4.1.4",
     "@types/react": "^19.0.0",
     "@types/react-dom": "^19.0.0",

packages/app/src/cli/services/app/env/lines-diff.test.ts

@@ -0,0 +1,119 @@
+import {diffLines} from './lines-diff.js'
+import {LinesDiffSegment} from '@shopify/cli-kit/node/output'
+import {describe, expect, test} from 'vitest'
+
+// These expectations were produced by `diff`'s `diffLines` (with the `count` field dropped) and
+// asserted byte-for-byte equal to the inlined `diffLines` helper while `diff` was still installed
+// (see the commit that removed the dependency). They are now frozen as static fixtures so the
+// parity guarantee is preserved without depending on `diff`. Each case targets an `.env` edge case
+// that the `app env pull` diff can encounter.
+
+interface DiffCase {
+  name: string
+  old: string
+  new: string
+  expected: LinesDiffSegment[]
+}
+
+const cases: DiffCase[] = [
+  {
+    name: 'the exact pull.test.ts ABC/XYZ case',
+    old: 'SHOPIFY_API_KEY=ABC\nSHOPIFY_API_SECRET=XYZ\nSCOPES=my-scope',
+    new: 'SHOPIFY_API_KEY=api-key\nSHOPIFY_API_SECRET=api-secret\nSCOPES=my-scope',
+    expected: [
+      {value: 'SHOPIFY_API_KEY=ABC\nSHOPIFY_API_SECRET=XYZ\n', removed: true},
+      {value: 'SHOPIFY_API_KEY=api-key\nSHOPIFY_API_SECRET=api-secret\n', added: true},
+      {value: 'SCOPES=my-scope'},
+    ],
+  },
+  {
+    name: 'multiline quoted values (value spanning multiple physical lines)',
+    old: 'FOO="line1\nline2"\nBAR=baz',
+    new: 'FOO="line1\nline2-edited"\nBAR=baz',
+    expected: [
+      {value: 'FOO="line1\n'},
+      {value: 'line2"\n', removed: true},
+      {value: 'line2-edited"\n', added: true},
+      {value: 'BAR=baz'},
+    ],
+  },
+  {
+    name: 'quote escaping changes',
+    old: 'FOO="a\\"b"\nBAR=1',
+    new: 'FOO="a\\\\b"\nBAR=1',
+    expected: [{value: 'FOO="a\\"b"\n', removed: true}, {value: 'FOO="a\\\\b"\n', added: true}, {value: 'BAR=1'}],
+  },
+  {
+    name: 'CRLF line endings with a changed line',
+    old: 'a\r\nb\r\nc\r\n',
+    new: 'a\r\nx\r\nc\r\n',
+    expected: [{value: 'a\r\n'}, {value: 'b\r\n', removed: true}, {value: 'x\r\n', added: true}, {value: 'c\r\n'}],
+  },
+  {
+    name: 'CRLF added and removed lines',
+    old: 'KEY=1\r\nOLD=2\r\n',
+    new: 'KEY=1\r\nNEW=3\r\nEXTRA=4\r\n',
+    expected: [{value: 'KEY=1\r\n'}, {value: 'OLD=2\r\n', removed: true}, {value: 'NEW=3\r\nEXTRA=4\r\n', added: true}],
+  },
+  {
+    name: 'trailing newline removed (last line loses its newline)',
+    old: 'a\nb\nc\n',
+    new: 'a\nb\nc',
+    expected: [{value: 'a\nb\n'}, {value: 'c\n', removed: true}, {value: 'c', added: true}],
+  },
+  {
+    name: 'trailing newline added (last line gains a newline)',
+    old: 'a\nb\nc',
+    new: 'a\nb\nc\n',
+    expected: [{value: 'a\nb\n'}, {value: 'c', removed: true}, {value: 'c\n', added: true}],
+  },
+  {
+    name: 'empty old string (file creation-ish)',
+    old: '',
+    new: 'SHOPIFY_API_KEY=api-key\nSCOPES=s',
+    expected: [{value: 'SHOPIFY_API_KEY=api-key\nSCOPES=s', added: true}],
+  },
+  {
+    name: 'identical strings (no changes)',
+    old: 'x\ny\nz',
+    new: 'x\ny\nz',
+    expected: [{value: 'x\ny\nz'}],
+  },
+  {
+    name: 'both empty strings',
+    old: '',
+    new: '',
+    expected: [{value: ''}],
+  },
+  {
+    name: 'pure addition at the end',
+    old: 'a\nb\nc',
+    new: 'a\nb\nc\nd\ne',
+    expected: [{value: 'a\nb\n'}, {value: 'c', removed: true}, {value: 'c\nd\ne', added: true}],
+  },
+  {
+    name: 'pure removal at the end',
+    old: 'a\nb\nc\nd\ne',
+    new: 'a\nb\nc',
+    expected: [{value: 'a\nb\n'}, {value: 'c\nd\ne', removed: true}, {value: 'c', added: true}],
+  },
+  {
+    name: 'interleaved changes',
+    old: 'a\nb\nc\nd',
+    new: 'x\nb\ny\nd',
+    expected: [
+      {value: 'a\n', removed: true},
+      {value: 'x\n', added: true},
+      {value: 'b\n'},
+      {value: 'c\n', removed: true},
+      {value: 'y\n', added: true},
+      {value: 'd'},
+    ],
+  },
+]
+
+describe('diffLines', () => {
+  test.each(cases)('produces the expected jsdiff-parity segments for: $name', ({old, new: updated, expected}) => {
+    expect(diffLines(old, updated)).toEqual(expected)
+  })
+})