Use a counter instead of Math.random for diagnostic filename suffix

lib/analyze-action.js

@@ -107850,6 +107850,7 @@ function formatDuration(durationMs) {
 // src/diagnostics.ts
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -107892,7 +107893,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

lib/init-action-post.js

@@ -165769,6 +165769,7 @@ function formatDuration(durationMs) {
 // src/diagnostics.ts
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -165811,7 +165812,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

lib/init-action.js

@@ -105355,6 +105355,7 @@ function formatDuration(durationMs) {
 // src/diagnostics.ts
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -105397,7 +105398,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

lib/setup-codeql-action.js

@@ -105425,6 +105425,7 @@ function formatDuration(durationMs) {
 // src/diagnostics.ts
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -105467,7 +105468,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

lib/upload-lib.js

@@ -107460,6 +107460,7 @@ function formatDuration(durationMs) {
 // src/diagnostics.ts
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -107502,7 +107503,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

lib/upload-sarif-action.js

@@ -108216,6 +108216,7 @@ var import_fs = require("fs");
 var import_path = __toESM(require("path"));
 var unwrittenDiagnostics = [];
 var unwrittenDefaultLanguageDiagnostics = [];
+var diagnosticCounter = 0;
 function makeDiagnostic(id, name, data = void 0) {
   return {
     ...data,
@@ -108258,7 +108259,7 @@ function writeDiagnostic(config, language, diagnostic) {
   );
   try {
     (0, import_fs.mkdirSync)(diagnosticsPath, { recursive: true });
-    const uniqueSuffix = Math.floor(Math.random() * 4294967296).toString(16).padStart(8, "0");
+    const uniqueSuffix = (diagnosticCounter++).toString();
     const sanitizedTimestamp = diagnostic.timestamp.replace(
       /[^a-zA-Z0-9.-]/g,
       ""

src/diagnostics.ts

@@ -72,6 +72,13 @@ let unwrittenDiagnostics: UnwrittenDiagnostic[] = [];
  */
 let unwrittenDefaultLanguageDiagnostics: DiagnosticMessage[] = [];
 
+/**
+ * Counter used to generate a unique suffix for each diagnostic filename, so that
+ * two diagnostics produced within the same millisecond do not overwrite each
+ * other on disk.
+ */
+let diagnosticCounter = 0;
+
 /**
  * Constructs a new diagnostic message with the specified id and name, as well as optional additional data.
  *
@@ -167,12 +174,9 @@ function writeDiagnostic(
     // Create the directory if it doesn't exist yet.
     mkdirSync(diagnosticsPath, { recursive: true });
 
-    // Include a random suffix to avoid filename collisions between diagnostics
-    // produced within the same millisecond. This doesn't need to be
-    // cryptographically secure, so `Math.random` is fine.
-    const uniqueSuffix = Math.floor(Math.random() * 0x100000000)
-      .toString(16)
-      .padStart(8, "0");
+    // Include a monotonically increasing suffix to avoid filename collisions
+    // between diagnostics produced within the same millisecond.
+    const uniqueSuffix = (diagnosticCounter++).toString();
     // We should only need to remove colons, but to be defensive, only allow a restricted set of
     // characters.
     const sanitizedTimestamp = diagnostic.timestamp.replace(