fix(bazel): integration rule using incorrect casing for working dir of commands

The integration rule currently directly takes the Bazel `TEST_TMP_DIR`
as directory for the integration test. Bazel will use a lower-case
variant of the path on case-insensitive platforms (like Windows). This
is acceptable for standard IO operations (as within Bazel), but can
unexpectedly break module resolution/or cause subtle differences.

We should always normalize the path to an actual case-exact system
realpath when setting it as `CWD` for command invocations. This
enables the use of e.g. playwright within Bazel integration tests.

microsoft/playwright#9193.

Author: devversion

bazel/integration/test_runner/BUILD.bazel

@@ -14,6 +14,7 @@ ts_library(
         "@npm//@types/node",
         "@npm//@types/tmp",
         "@npm//tmp",
+        "@npm//true-case-path",
     ],
 )
 

bazel/integration/test_runner/file_system_utils.ts

@@ -7,6 +7,7 @@
  */
 
 import * as fs from 'fs';
+import {trueCasePath} from 'true-case-path';
 
 /** Gets whether the file is executable or not. */
 export async function isExecutable(filePath: string): Promise<boolean> {
@@ -18,6 +19,16 @@ export async function isExecutable(filePath: string): Promise<boolean> {
   }
 }
 
+/**
+ * Gets a case-exact system realpath for the specified path.
+ *
+ * This is useful for example because Bazel passes `C:\users\<..>` as action input, but
+ * the actual case-exact path for the current platform would be: `C:\Users\<..>`.
+ */
+export async function getCaseExactRealpath(filePath: string): Promise<string> {
+  return trueCasePath(filePath);
+}
+
 /** Adds the `write` permission to the given file using `chmod`. */
 export async function addWritePermissionFlag(filePath: string) {
   if (await isExecutable(filePath)) {

bazel/integration/test_runner/process_utils.ts

@@ -9,6 +9,7 @@
 import * as childProcess from 'child_process';
 import * as path from 'path';
 import {debug} from './debug';
+import {getCaseExactRealpath} from './file_system_utils';
 
 /**
  * Regular expression matching environment variable substitutions
@@ -41,21 +42,26 @@ export function expandEnvironmentVariableSubstitutions(
  * @returns a Promise that resolves with a boolean indicating whether the
  *   command completed successfully or not.
  */
-export function runCommandInChildProcess(
+export async function runCommandInChildProcess(
   binary: string,
   args: string[],
   workingDir: string,
   env: NodeJS.ProcessEnv,
 ): Promise<boolean> {
   const humanReadableCommand = `${binary}${args.length ? ` ${args.join(' ')}` : ''}`;
+  // Note: We resolve the working directory to a case-exact system `realpath`. This is
+  // necessary as otherwise Node module resolution could behave unexpectedly when invoked
+  // tools down-the-line resolve files with an actual system realpath. Here is an example
+  // within Microsoft's `playwright`: https://github.com/microsoft/playwright/issues/9193.
+  const normalizedWorkingDir = await getCaseExactRealpath(path.posix.normalize(workingDir));
 
-  debug(`Executing command: ${humanReadableCommand} in ${workingDir}`);
+  debug(`Executing command: ${humanReadableCommand} in ${normalizedWorkingDir}`);
 
   return new Promise<boolean>((resolve) => {
     const commandProcess = childProcess.spawn(binary, args, {
       shell: true,
       stdio: 'inherit',
-      cwd: workingDir,
+      cwd: normalizedWorkingDir,
       env,
     });
 

package.json

@@ -56,6 +56,7 @@
     "selenium-webdriver": "3.5.0",
     "semver": "^7.3.5",
     "tmp": "^0.2.1",
+    "true-case-path": "^2.2.1",
     "ts-node": "^10.2.1",
     "tslib": "^2.3.0",
     "tslint": "^6.1.3",

yarn.lock

@@ -3091,6 +3091,11 @@ trim-newlines@^3.0.0:
   resolved "https://registry.yarnpkg.com/trim-newlines/-/trim-newlines-3.0.1.tgz#260a5d962d8b752425b32f3a7db0dcacd176c144"
   integrity sha512-c1PTsA3tYrIsLGkJkzHF+w9F2EyxfXGo4UyJc4pFL++FMjnq0HJS69T3M7d//gKrFKwy429bouPescbjecU+Zw==
 
+"true-case-path@^2.2.1":
+  version "2.2.1"
+  resolved "https://registry.yarnpkg.com/true-case-path/-/true-case-path-2.2.1.tgz#c5bf04a5bbec3fd118be4084461b3a27c4d796bf"
+  integrity sha512-0z3j8R7MCjy10kc/g+qg7Ln3alJTodw9aDuVWZa3uiWqfuBMKeAeP2ocWcxoyM3D73yz3Jt/Pu4qPr4wHSdB/Q==
+
 ts-node@^10.2.1:
   version "10.4.0"
   resolved "https://registry.yarnpkg.com/ts-node/-/ts-node-10.4.0.tgz#680f88945885f4e6cf450e7f0d6223dd404895f7"