Keep released lock-sidecar cleanup buildable with MSVC

Use the MSVC stack allocator when preparing released amalgamations that contain a variable-length lock-path array. Preserve the source everywhere else and keep existing releases usable with the Windows publishing toolchain.

Co-Authored-By: OpenAI Codex <noreply@openai.com>

Author: Tim

scripts/build-amalgamation.js

@@ -32,6 +32,22 @@ console.log("Preparing released doltlite amalgamation...")
 fs.mkdirSync(outDir, { recursive: true })
 let amalgamation = fs.readFileSync(inC, "utf8")
 
+const lockPathVla = '  char zLock[nDir + (nPath - nDir) + sizeof(".-lock") + 1];'
+if (amalgamation.includes(lockPathVla)) {
+  amalgamation = `/* DOLTLITE_NODE_MSVC_LOCK_PATH_FALLBACK */
+#ifdef _MSC_VER
+# include <malloc.h>
+#endif
+
+${amalgamation.replace(lockPathVla, [
+    "#ifdef _MSC_VER",
+    '  char *zLock = (char*)_alloca(nPath + sizeof(".-lock"));',
+    "#else",
+    lockPathVla,
+    "#endif",
+  ].join("\n"))}`
+}
+
 // DoltLite releases before v0.11.37 emitted the Winsock 2 headers after
 // SQLite's Windows VFS had already included windows.h.  Keep those releases
 // buildable while newer release amalgamations carry the ordering fix directly.

test/amalgamation.test.ts

@@ -27,14 +27,27 @@ describe("released amalgamation preparation", () => {
     expect(winsock).toBeLessThan(windows)
   })
 
-  test("uses an unmodified fixed release amalgamation", () => {
+  test("keeps lock-path allocation on the stack with MSVC", () => {
     const source = readFileSync(sourcePath, "utf8")
     const output = readFileSync(outputPath, "utf8")
+    const vla = '  char zLock[nDir + (nPath - nDir) + sizeof(".-lock") + 1];'
 
-    if (source.includes("DOLTLITE_AMALGAMATION_WINSOCK2_EARLY")) {
-      expect(output).toBe(source)
-    } else {
-      expect(output).toContain("DOLTLITE_NODE_WINSOCK2_EARLY_FALLBACK")
+    if (source.includes(vla)) {
+      expect(output).toContain("DOLTLITE_NODE_MSVC_LOCK_PATH_FALLBACK")
+      expect(output).toContain('#ifdef _MSC_VER\n  char *zLock = (char*)_alloca(nPath + sizeof(".-lock"));')
+      expect(output).toContain(`#else\n${vla}\n#endif`)
     }
   })
+
+  test("preserves release source outside compiler compatibility fixes", () => {
+    const source = readFileSync(sourcePath, "utf8")
+    const output = readFileSync(outputPath, "utf8")
+    const vla = '  char zLock[nDir + (nPath - nDir) + sizeof(".-lock") + 1];'
+    const restored = output
+      .replace(/^\/\* DOLTLITE_NODE_WINSOCK2_EARLY_FALLBACK \*\/\n#ifdef _WIN32\n# include <winsock2.h>\n# include <ws2tcpip.h>\n#endif\n\n/, "")
+      .replace(/^\/\* DOLTLITE_NODE_MSVC_LOCK_PATH_FALLBACK \*\/\n#ifdef _MSC_VER\n# include <malloc.h>\n#endif\n\n/, "")
+      .replace(`#ifdef _MSC_VER\n  char *zLock = (char*)_alloca(nPath + sizeof(".-lock"));\n#else\n${vla}\n#endif`, vla)
+
+    expect(restored).toBe(source)
+  })
 })