feat: implement realisePath

nix-js/runtime-ts/src/builtins/conversion.ts

@@ -86,7 +86,7 @@ export const coerceToString = (
   value: NixValue,
   mode: StringCoercionMode,
   copyToStore: boolean = false,
-  outContext?: NixStringContext,
+  outContext: NixStringContext,
 ): string => {
   const v = force(value);
 
@@ -96,10 +96,8 @@ export const coerceToString = (
   }
 
   if (isStringWithContext(v)) {
-    if (outContext) {
+    for (const elem of v.context) {
-      for (const elem of v.context) {
+      outContext.add(elem);
-        outContext.add(elem);
-      }
     }
     return v.value;
   }
@@ -109,9 +107,7 @@ export const coerceToString = (
     if (copyToStore) {
       const pathStr = v.value;
       const storePath = Deno.core.ops.op_copy_path_to_store(pathStr);
-      if (outContext) {
+      outContext.add(storePath);
-        outContext.add(storePath);
-      }
       return storePath;
     }
     return v.value;
@@ -253,7 +249,7 @@ export const coerceToStringWithContext = (
  * - Returns the path string (not a NixPath object)
  * - Preserves string context if present
  */
-export const coerceToPath = (value: NixValue, outContext?: NixStringContext): string => {
+export const coerceToPath = (value: NixValue, outContext: NixStringContext): string => {
   const forced = force(value);
 
   if (isPath(forced)) {
@@ -347,10 +343,8 @@ export const nixValueToJson = (
       return result;
     }
     if (isStringWithContext(result)) {
-      if (outContext) {
+      for (const elem of result.context) {
-        for (const elem of result.context) {
+        outContext.add(elem);
-          outContext.add(elem);
-        }
       }
       return result.value;
     }

nix-js/runtime-ts/src/builtins/functional.ts

@@ -41,7 +41,7 @@ export const abort = (s: NixValue): never => {
 };
 
 export const throwFunc = (s: NixValue): never => {
-  throw new CatchableError(coerceToString(s, StringCoercionMode.Base));
+  throw new CatchableError(coerceToString(s, StringCoercionMode.Base, false, new Set()));
 };
 
 export const trace =

nix-js/runtime-ts/src/builtins/hash.ts

@@ -1,10 +1,12 @@
 import { forceStringNoCtx } from "../type-assert";
 import type { NixValue } from "../types";
+import { realisePath } from "./io";
 
 export const hashFile =
   (type: NixValue) =>
-  (_p: NixValue): never => {
+  (p: NixValue): string => {
     const _ty = forceStringNoCtx(type);
+    const _pathStr = realisePath(p);
     throw new Error("Not implemented: hashFile");
   };
 

nix-js/runtime-ts/src/builtins/io.ts

@@ -1,6 +1,6 @@
 import { getPathValue } from "../path";
 import type { NixStringContext, StringWithContext } from "../string-context";
-import { addOpaqueContext, mkStringWithContext } from "../string-context";
+import { addOpaqueContext, decodeContextElem, mkStringWithContext } from "../string-context";
 import { force } from "../thunk";
 import {
   forceAttrs,
@@ -14,32 +14,40 @@ import type { NixAttrs, NixPath, NixString, NixValue } from "../types";
 import { CatchableError, IS_PATH, isNixPath } from "../types";
 import { coerceToPath, coerceToString, StringCoercionMode } from "./conversion";
 import { baseNameOf } from "./path";
-import { isAttrs, isPath } from "./type-check";
+import { isAttrs, isPath, isString } from "./type-check";
 
 const importCache = new Map<string, NixValue>();
 
-export const importFunc = (path: NixValue): NixValue => {
+const realiseContext = (context: NixStringContext): void => {
-  const context: NixStringContext = new Set();
+  for (const encoded of context) {
-  const pathStr = coerceToPath(path, context);
+    const elem = decodeContextElem(encoded);
-
+    if (elem.type === "built") {
-  // FIXME: Context collected but not yet propagated to build system
+      throw new Error(
-  // This means derivation dependencies from imported paths are not
+        `cannot build derivation '${elem.drvPath}' during evaluation because import-from-derivation is not supported`,
-  // currently tracked. This will cause issues when:
+      );
-  // 1. Importing from derivation outputs: import "${drv}/file.nix"
+    }
-  // 2. Building packages that depend on imported configurations
-  if (context.size > 0) {
-    console.warn(
-      `[WARN] import: Path has string context which is not yet fully tracked.
-Dependency tracking for imported derivations may be incomplete.`,
-    );
   }
+};
+
+export const realisePath = (value: NixValue): string => {
+  const context: NixStringContext = new Set();
+  const pathStr = coerceToPath(value, context);
+
+  if (context.size > 0) {
+    realiseContext(context);
+  }
+
+  return pathStr;
+};
+
+export const importFunc = (path: NixValue): NixValue => {
+  const pathStr = realisePath(path);
 
   const cached = importCache.get(pathStr);
   if (cached !== undefined) {
     return cached;
   }
 
-  // Call Rust op - returns JS code string
   const code = Deno.core.ops.op_import(pathStr);
   const result = Function(`return (${code})`)();
 
@@ -53,15 +61,7 @@ export const scopedImport =
     const scopeAttrs = forceAttrs(scope);
     const scopeKeys = Object.keys(scopeAttrs);
 
-    const context: NixStringContext = new Set();
+    const pathStr = realisePath(path);
-    const pathStr = coerceToPath(path, context);
-
-    if (context.size > 0) {
-      console.warn(
-        `[WARN] scopedImport: Path has string context which is not yet fully tracked.
-Dependency tracking for imported derivations may be incomplete.`,
-      );
-    }
 
     const code = Deno.core.ops.op_scoped_import(pathStr, scopeKeys);
 
@@ -169,9 +169,10 @@ export const fetchTarball = (args: NixValue): NixString => {
 
 export const fetchGit = (args: NixValue): NixAttrs => {
   const forced = force(args);
-  if (typeof forced === "string" || isPath(forced)) {
+  const disposedContext: NixStringContext = new Set();
-    const path = coerceToPath(forced);
+  if (isString(forced) || isPath(forced)) {
-    const result: FetchGitResult = Deno.core.ops.op_fetch_git(path, null, null, false, false, false, null);
+    const url = coerceToString(forced, StringCoercionMode.Base, false, disposedContext);
+    const result = Deno.core.ops.op_fetch_git(url, null, null, false, false, false, null);
     const outContext: NixStringContext = new Set();
     addOpaqueContext(outContext, result.out_path);
     return {
@@ -303,7 +304,7 @@ const autoDetectAndFetch = (attrs: NixAttrs): NixAttrs => {
 };
 
 export const readDir = (path: NixValue): NixAttrs => {
-  const pathStr = coerceToPath(path);
+  const pathStr = realisePath(path);
   const entries: Record<string, string> = Deno.core.ops.op_read_dir(pathStr);
   const result: NixAttrs = {};
   for (const [name, type] of Object.entries(entries)) {
@@ -313,18 +314,22 @@ export const readDir = (path: NixValue): NixAttrs => {
 };
 
 export const readFile = (path: NixValue): string => {
-  const pathStr = coerceToPath(path);
+  const pathStr = realisePath(path);
   return Deno.core.ops.op_read_file(pathStr);
 };
 
 export const readFileType = (path: NixValue): string => {
-  const pathStr = coerceToPath(path);
+  const pathStr = realisePath(path);
   return Deno.core.ops.op_read_file_type(pathStr);
 };
 
 export const pathExists = (path: NixValue): boolean => {
-  const pathStr = coerceToPath(path);
+  try {
-  return Deno.core.ops.op_path_exists(pathStr);
+    const pathStr = realisePath(path);
+    return Deno.core.ops.op_path_exists(pathStr);
+  } catch {
+    return false;
+  }
 };
 
 /**

nix-js/runtime-ts/src/builtins/path.ts

@@ -2,7 +2,7 @@ import { mkPath } from "../path";
 import { mkStringWithContext, type NixStringContext } from "../string-context";
 import { force } from "../thunk";
 import type { NixPath, NixString, NixValue } from "../types";
-import { isNixPath, isStringWithContext } from "../types";
+import { isNixPath } from "../types";
 import { coerceToPath, coerceToString, StringCoercionMode } from "./conversion";
 
 /**
@@ -86,21 +86,8 @@ export const dirOf = (s: NixValue): NixPath | NixString => {
   }
 
   // String input → string output
-  const strValue: NixString = coerceToString(s, StringCoercionMode.Base, false) as NixString;
+  const outContext: NixStringContext = new Set();
-
+  const pathStr = coerceToString(s, StringCoercionMode.Base, false, outContext);
-  let pathStr: string;
-  let hasContext = false;
-  let originalContext: Set<string> | undefined;
-
-  if (typeof strValue === "string") {
-    pathStr = strValue;
-  } else if (isStringWithContext(strValue)) {
-    pathStr = strValue.value;
-    hasContext = strValue.context.size > 0;
-    originalContext = strValue.context;
-  } else {
-    pathStr = strValue as string;
-  }
 
   const lastSlash = pathStr.lastIndexOf("/");
 
@@ -113,9 +100,8 @@ export const dirOf = (s: NixValue): NixPath | NixString => {
 
   const result = pathStr.slice(0, lastSlash);
 
-  // Preserve string context if present
+  if (outContext.size > 0) {
-  if (hasContext && originalContext) {
+    return mkStringWithContext(result, outContext);
-    return mkStringWithContext(result, originalContext);
   }
 
   return result;