fix: improve path segment extraction for multi-instance docs

Refactors the path extraction logic in both index.ts and sidebars/index.ts
to use segment-by-segment matching instead of string splitting. This fixes
edge cases where docPath appears multiple times in outputDir or when paths
have inconsistent leading/trailing slashes.

Changes:
- Normalize paths by removing leading ./ and leading/trailing slashes
- Match docPath segments within outputDir segments sequentially
- Clean up double slashes in the resulting infoBasePath

Fixes #1305

Author: trofim24

packages/docusaurus-plugin-openapi-docs/src/index.ts

@@ -368,17 +368,25 @@ custom_edit_url: null
           let infoBasePath = `${outputDir}/${item.infoId}`;
           if (docRouteBasePath) {
             // Safely extract path segment, handling cases where docPath may not be in outputDir
-            const outputSegment =
-              docPath && outputDir.includes(docPath)
-                ? (outputDir.split(docPath)[1]?.replace(/^\/+/g, "") ?? "")
-                : outputDir
-                    .slice(outputDir.indexOf("/", 1))
-                    .replace(/^\/+/g, "");
-            infoBasePath =
-              `${docRouteBasePath}/${outputSegment}/${item.infoId}`.replace(
-                /^\/+/g,
-                ""
-              );
+            const normalize = (p: string): string =>
+              p.replace(/^\.\//, "").replace(/^\/+|\/+$/g, "");
+            const outputSegments = normalize(outputDir).split("/").filter(Boolean);
+            let outputSegment = outputSegments.slice(1).join("/"); // fallback
+            if (docPath) {
+              const docSegments = normalize(docPath).split("/").filter(Boolean);
+              for (let i = 0; i <= outputSegments.length - docSegments.length; i++) {
+                const match = docSegments.every(
+                  (seg, j) => outputSegments[i + j] === seg
+                );
+                if (match) {
+                  outputSegment = outputSegments.slice(i + docSegments.length).join("/");
+                  break;
+                }
+              }
+            }
+            infoBasePath = `${docRouteBasePath}/${outputSegment}/${item.infoId}`
+              .replace(/^\/+/g, "")
+              .replace(/\/+/g, "/");
           }
           if (item.infoId) item.infoPath = infoBasePath;
         }

packages/docusaurus-plugin-openapi-docs/src/sidebars/index.ts

@@ -130,13 +130,29 @@ function groupByTags(
     output: string,
     doc: string | undefined
   ): string => {
-    if (doc && output.includes(doc)) {
-      return output.split(doc)[1]?.replace(/^\/+/g, "") ?? "";
+    // Normalize path: remove leading ./ and leading/trailing slashes
+    const normalize = (p: string): string =>
+      p.replace(/^\.\//, "").replace(/^\/+|\/+$/g, "");
+
+    const outputSegments = normalize(output).split("/").filter(Boolean);
+
+    if (doc) {
+      const docSegments = normalize(doc).split("/").filter(Boolean);
+
+      // Find where docSegments sequence appears in outputSegments
+      for (let i = 0; i <= outputSegments.length - docSegments.length; i++) {
+        const match = docSegments.every(
+          (seg, j) => outputSegments[i + j] === seg
+        );
+        if (match) {
+          // Return everything after the matched sequence
+          return outputSegments.slice(i + docSegments.length).join("/");
+        }
+      }
     }
-    const slashIndex = output.indexOf("/", 1);
-    return slashIndex === -1
-      ? ""
-      : output.slice(slashIndex).replace(/^\/+/g, "");
+
+    // Fallback: return everything after first segment
+    return outputSegments.slice(1).join("/");
   };
 
   const basePath = getBasePathFromOutput(outputDir, docPath);