perf: do not load disabled source files

components/agent/default/index.mjs

@@ -79,7 +79,7 @@ export const instrument = (
   const source = createSource(url, content);
   const mapping = loadSourceMap(source, map);
   if (configuration["postmortem-function-exclusion"] !== true) {
-    fillSourceMap(mapping);
+    fillSourceMap(mapping, configuration);
   }
   const { messages, content: instrumented_content } = instrumentFrontend(
     frontend,

components/agent/default/source-map.mjs

@@ -10,25 +10,28 @@ import {
   isSourceEmpty,
   getSourceUrl,
 } from "../../source/index.mjs";
+import { getConfigurationPackage } from "../../configuration-accessor/index.mjs";
 import { readFile } from "../../file/index.mjs";
 import { logDebug } from "../../log/index.mjs";
 
-export const fillSourceMap = (mapping) => {
+export const fillSourceMap = (mapping, configuration) => {
   for (const url of getMappingSourceArray(mapping)
     .filter(isSourceEmpty)
     .map(getSourceUrl)) {
-    let content = null;
-    try {
-      // TODO
-      // Lookup the url in `configuration.packages` to see whether the url is
-      // enabled. If it is disabled, we can improve performance by not trying
-      // to load the source file.
-      content = readFile(url);
-    } catch (error) {
-      logDebug("could not load source file %j >> %O", url, error);
-    }
-    if (content !== null) {
-      updateMappingSource(mapping, createSource(url, content));
+    if (getConfigurationPackage(configuration, url).enabled) {
+      let content = null;
+      try {
+        // TODO
+        // Lookup the url in `configuration.packages` to see whether the url is
+        // enabled. If it is disabled, we can improve performance by not trying
+        // to load the source file.
+        content = readFile(url);
+      } catch (error) {
+        logDebug("could not load source file %j >> %O", url, error);
+      }
+      if (content !== null) {
+        updateMappingSource(mapping, createSource(url, content));
+      }
     }
   }
 };

components/agent/default/source-map.test.mjs

@@ -3,6 +3,10 @@ import { Buffer } from "node:buffer";
 import { assertEqual, assertDeepEqual } from "../../__fixture__.mjs";
 import { getUuid } from "../../uuid/random/index.mjs";
 import { createSource, makeSourceLocation } from "../../source/index.mjs";
+import {
+  extendConfiguration,
+  createConfiguration,
+} from "../../configuration/index.mjs";
 import { getTmpUrl } from "../../path/index.mjs";
 import { toAbsoluteUrl } from "../../url/index.mjs";
 import {
@@ -27,11 +31,18 @@ const empty_source_map = {
 };
 
 {
+  const configuration = extendConfiguration(
+    createConfiguration(getTmpUrl()),
+    {
+      "default-package": { enabled: true },
+    },
+    getTmpUrl(),
+  );
   const url = toAbsoluteUrl(getUuid(), getTmpUrl());
   const mapping = createMirrorMapping(createSource(url, null));
-  fillSourceMap(mapping);
+  fillSourceMap(mapping, configuration);
   await writeFileAsync(new URL(url), "123;", "utf8");
-  fillSourceMap(mapping);
+  fillSourceMap(mapping, configuration);
   assertDeepEqual(getMappingSourceArray(mapping), [createSource(url, "123;")]);
 }