fix: Cover edge case issues with case-insensitive filesystems

src/utils/general-utils.ts

@@ -1,30 +1,15 @@
 import url from "url";
 import path from "path";
-import { realpathSync } from "fs";
 
 /* ****************************************************************************************************************** *
  * General Utilities & Helpers
  * ****************************************************************************************************************** */
 
 export const isURL = (s: string): boolean => !!s && (!!url.parse(s).host || !!url.parse(s).hostname);
 
-export const cast = <T>(v: any): T => v;
-
 export const isBaseDir = (baseDir: string, testDir: string): boolean => {
   const relative = path.relative(baseDir, testDir);
   return relative ? !relative.startsWith("..") && !path.isAbsolute(relative) : true;
 };
 
 export const maybeAddRelativeLocalPrefix = (p: string) => (p[0] === "." ? p : `./${p}`);
-
-export function tryRealpathNative(value: string) {
-  try {
-    return realpathSync.native(value);
-  } catch {
-    return value;
-  }
-}
-
-export function nativeRelativePath(from: string, to: string) {
-  return path.relative(tryRealpathNative(from), tryRealpathNative(to));
-}

src/utils/get-relative-path.ts

@@ -0,0 +1,85 @@
+import fs from "fs";
+import * as os from "os";
+import path from "path";
+
+/* ****************************************************************************************************************** */
+// region: Locals
+/* ****************************************************************************************************************** */
+
+let isCaseSensitiveFilesystem: boolean | undefined;
+
+// endregion
+
+/* ****************************************************************************************************************** */
+// region: Helpers
+/* ****************************************************************************************************************** */
+
+function tryRmFile(fileName: string) {
+  try {
+    if (fs.existsSync(fileName)) fs.rmSync(fileName, { force: true });
+  } catch {}
+}
+
+function getIsFsCaseSensitive() {
+  if (isCaseSensitiveFilesystem != null) return isCaseSensitiveFilesystem;
+
+  for (let i = 0; i < 1000; i++) {
+    const tmpFileName = path.join(os.tmpdir(), `tstp~${i}.tmp`);
+
+    tryRmFile(tmpFileName);
+
+    try {
+      fs.writeFileSync(tmpFileName, "");
+      isCaseSensitiveFilesystem = !fs.existsSync(tmpFileName.replace("tstp", "TSTP"));
+      return isCaseSensitiveFilesystem;
+    } catch {
+    } finally {
+      tryRmFile(tmpFileName);
+    }
+  }
+
+  console.warn(
+    `Could not determine filesystem's case sensitivity. Please file a bug report with your system's details`
+  );
+  isCaseSensitiveFilesystem = false;
+
+  return isCaseSensitiveFilesystem;
+}
+
+function getMatchPortion(from: string, to: string) {
+  const lowerFrom = from.toLocaleLowerCase();
+  const lowerTo = to.toLocaleLowerCase();
+
+  const maxLen = Math.max(lowerFrom.length, lowerTo.length);
+
+  let i = 0;
+  while (i < maxLen) {
+    if (lowerFrom[i] !== lowerTo[i]) break;
+    i++;
+  }
+
+  return from.slice(0, i);
+}
+
+// endregion
+
+/* ****************************************************************************************************************** */
+// region: Utils
+/* ****************************************************************************************************************** */
+
+export function getRelativePath(from: string, to: string) {
+  try {
+    from = fs.realpathSync.native(from);
+    to = fs.realpathSync.native(to);
+  } catch {
+    if (!getIsFsCaseSensitive()) {
+      const matchPortion = getMatchPortion(from, to);
+      from = matchPortion + from.slice(matchPortion.length);
+      to = matchPortion + to.slice(matchPortion.length);
+    }
+  }
+
+  return path.relative(from, to);
+}
+
+// endregion

src/utils/resolve-module-name.ts

@@ -1,8 +1,9 @@
 import { VisitorContext } from "../types";
-import { isBaseDir, isURL, maybeAddRelativeLocalPrefix, nativeRelativePath } from "./general-utils";
+import { isBaseDir, isURL, maybeAddRelativeLocalPrefix } from "./general-utils";
 import * as path from "path";
 import { removeFileExtension, removeSuffix, ResolvedModuleFull, SourceFile } from "typescript";
 import { getOutputDirForSourceFile } from "./ts-helpers";
+import { getRelativePath } from "./get-relative-path";
 
 /* ****************************************************************************************************************** */
 // region: Types
@@ -167,12 +168,12 @@ export function resolveModuleName(context: VisitorContext, moduleName: string):
 
     /* Remove base dirs to make relative to root */
     if (fileRootDir && moduleRootDir) {
-      srcFileOutputDir = nativeRelativePath(fileRootDir, srcFileOutputDir);
-      moduleFileOutputDir = nativeRelativePath(moduleRootDir, moduleFileOutputDir);
+      srcFileOutputDir = getRelativePath(fileRootDir, srcFileOutputDir);
+      moduleFileOutputDir = getRelativePath(moduleRootDir, moduleFileOutputDir);
     }
   }
 
-  const outputDir = nativeRelativePath(srcFileOutputDir, moduleFileOutputDir);
+  const outputDir = getRelativePath(srcFileOutputDir, moduleFileOutputDir);
 
   /* Compose final output path */
   const outputPath = maybeAddRelativeLocalPrefix(tsInstance.normalizePath(path.join(outputDir, outputBaseName)));