Fix DVC cwd for Windows (#1921)

* fix DVC cwd on Windows

* add integration test in environment where fs is available

* add system specific test

Co-authored-by: Stephanie Roy <[email protected]>

Author: mattseddon

extension/src/cli/cwd.ts

@@ -0,0 +1,11 @@
+import { realpathSync } from 'fs'
+
+export const getCaseSensitiveCwd = (path: string): string => {
+  try {
+    const cwd = realpathSync.native(path)
+    if (cwd) {
+      return cwd
+    }
+  } catch {}
+  return path
+}

extension/src/cli/options.ts

@@ -1,5 +1,6 @@
 import { dirname } from 'path'
 import { Args } from './constants'
+import { getCaseSensitiveCwd } from './cwd'
 import { getProcessEnv } from '../env'
 import { joinEnvPath } from '../util/env'
 
@@ -45,13 +46,11 @@ export const getOptions = (
 ): ExecutionDetails => {
   const executable = getExecutable(pythonBinPath, cliPath)
   const args = getArgs(pythonBinPath, cliPath, ...originalArgs)
-  const command = [executable, ...args].join(' ')
-  const env = getEnv(pythonBinPath)
   return {
     args,
-    command,
-    cwd,
-    env,
+    command: [executable, ...args].join(' '),
+    cwd: getCaseSensitiveCwd(cwd),
+    env: getEnv(pythonBinPath),
     executable
   }
 }

extension/src/test/suite/cli/cwd.test.ts

@@ -0,0 +1,32 @@
+import { sep } from 'path'
+import { describe, it, suite } from 'mocha'
+import { expect } from 'chai'
+import { dvcDemoPath } from '../../util'
+import { getCaseSensitiveCwd } from '../../../cli/cwd'
+
+suite('Cwd Test Suite', () => {
+  describe('getCaseSensitiveCwd', () => {
+    it('should return a case sensitive path for case sensitive systems which matches os.getcwd() in the CLI', () => {
+      const caseInsensitiveCwd = dvcDemoPath.toUpperCase()
+      const realpathCwd = getCaseSensitiveCwd(caseInsensitiveCwd)
+
+      expect(realpathCwd).to.have.length(dvcDemoPath.length)
+      expect(realpathCwd).not.to.equal(
+        ['win32', 'darwin'].includes(process.platform)
+          ? caseInsensitiveCwd
+          : caseInsensitiveCwd.toLowerCase(),
+        'should behave differently on different systems'
+      )
+
+      const caseInsensitiveArray = caseInsensitiveCwd.split(sep)
+      const realPathArray = realpathCwd.split(sep)
+
+      expect(caseInsensitiveArray).to.have.length(realPathArray.length)
+      for (let i = 0; i <= caseInsensitiveArray.length; i++) {
+        expect(caseInsensitiveArray[i]).to.match(
+          new RegExp(realPathArray[i], 'i')
+        )
+      }
+    })
+  })
+})