The first Uncaught error is now saved to a file in Storage called ERROR (E.setFlags({noErrorSave:true}) disables this) (#2583)

Author: gfwilliams

ChangeLog

@@ -9,6 +9,7 @@
             Error.stack/stack dump now uses more standard file:line:col format
             Out of memory errors now show a backtrace (previously it was very hard to track these down)
             Increase chars shown in strings in console to 60
+            The first Uncaught error is now saved to a file in Storage called ERROR (`E.setFlags({noErrorSave:true})` disables this) (#2583)
 
      2v26 : nRF5x: ensure TIMER1_IRQHandler doesn't always wake idle loop up (fix #1900)
             Puck.js: On v2.1 ensure Puck.mag behaves like other variants - just returning the last reading (avoids glitches when used with Puck.magOn)

src/jsflags.h

@@ -25,12 +25,13 @@ typedef enum {
   JSF_PRETOKENISE         = 1<<3, ///< When adding functions, pre-minify them and tokenise reserved words (adding "ram" at the start does this too)
 #endif
 #ifdef ESPR_JIT
-  JSF_JIT_DEBUG           = 1<<4, ///< When JIT enabled,
+  JSF_JIT_DEBUG           = 1<<4, ///< When JIT enabled, output debugging info
 #endif
+  JSF_NO_ERRORS_SAVE      = 1<<5, ///< If set, do not attempt to save errors to internal Storage
 } PACKED_FLAGS JsFlags;
 
 
-#define JSFLAG_NAMES "deepSleep\0unsafeFlash\0unsyncFiles\0pretokenise\0jitDebug\0"
+#define JSFLAG_NAMES "deepSleep\0unsafeFlash\0unsyncFiles\0pretokenise\0jitDebug\0noErrorSave\0"
 // NOTE: \0 also added by compiler - two \0's are required!
 
 extern volatile JsFlags jsFlags;

src/jsinteractive.c

@@ -954,12 +954,20 @@ void jsiSemiInit(bool autoLoad, JsfFileName *loadedFilename) {
 #ifdef ESP8266
       jshPrintBanner();
 #endif
+#ifndef SAVE_ON_FLASH
+    if (jsfFindFile(jsfNameFromString("ERROR"),NULL))
+      jsiConsolePrint("\nAn Uncaught Error has been saved to Storage. Please type:\n"
+                        "  require('Storage').read('ERROR') to view it\n"
+                        "  require('Storage').erase('ERROR') to clear it\n");
+#endif
+
     }
 #ifdef USE_TERMINAL
     if (consoleDevice != EV_TERMINAL) // don't spam the terminal
 #endif
       jsiConsolePrint("\n"); // output new line
     inputLineRemoved = true; // we need to put the input line back...
+
   }
 
 #ifdef BANGLEJS // On Bangle.js if Storage is corrupt, show a recovery menu
@@ -1289,13 +1297,31 @@ void jsiCheckErrors() {
     jsiConsoleRemoveInputLine();
     jsiConsolePrintf("Uncaught %v\n", exception);
     reportedError = true;
+#ifndef SAVE_ON_FLASH
+    JsVar *exceptionString = NULL;
+    if ((!jsfGetFlag(JSF_NO_ERRORS_SAVE)) && !jsfFindFile(jsfNameFromString("ERROR"),NULL))
+      exceptionString = jsvAsString(exception);
+#endif
+
     if (jsvIsObject(exception)) {
       JsVar *stackTrace = jsvObjectGetChildIfExists(exception, "stack");
       if (stackTrace) {
         jsiConsolePrintStringVar(stackTrace);
+#ifndef SAVE_ON_FLASH
+        if (exceptionString) {
+          jsvAppendCharacter(exceptionString, '\n');
+          jsvAppendStringVarComplete(exceptionString, stackTrace);
+        }
+#endif
         jsvUnLock(stackTrace);
       }
     }
+#ifndef SAVE_ON_FLASH
+    if (exceptionString) {
+      jsfWriteFile(jsfNameFromString("ERROR"), exceptionString, JSFF_NONE, 0, 0);
+      jsvUnLock(exceptionString);
+    }
+#endif
   }
   jsvUnLock(exception);
   if (jspIsInterrupted()

src/jswrap_espruino.c

@@ -851,6 +851,10 @@ code.
 * `unsyncFiles` - When writing files, *don't* flush all data to the SD card
   after each command (the default is *to* flush). This is much faster, but can
   cause filesystem damage if power is lost without the filesystem unmounted.
+* `jitDebug` - When JIT compiling, outputs debug info to the console
+* `noErrorSave` - [2v27+] when an uncaught error occurs, by default it is now
+   written to a file called `ERROR` in Storage (the file is not updated). To
+   stop this happening, use `E.setFlags({noErrorSave:true})`
 */
 /*JSON{
   "type" : "staticmethod",