Deprecate SPIFFS, move examples to LittleFS (#7263)

* Deprecate SPIFFS, move examples to LittleFS

SPIFFS has been a great filesystem, but it has significant problems in
many cases (and it's also pretty slow).  Development seems to have
slowed/stopped on the upstream version, and we're not able to provide
support or fix the known issues with it as-is.

Deprecate SPIFFS variable.

Update all examples to use LittleFS instead of SPIFFS.

Also, minor cleanup on very old examples which has obsolete delays
waiting for the Serial port to come up, or which were stuck at 9600 baud
because of their ancient AVR heritage.

Fixes #7095

* Remove leftover debug code

* Clean up comments in some examples

* Update documentation on SPIFFS deprecation

* Fix host tests to avoid deprecation warnings

* Fix cut-n-paste error

* Restore SpeedTest.ino, adjust to allow custom FSes

Co-authored-by: Develo <deveyes@gmail.com>

doc/boards.rst

@@ -344,7 +344,7 @@ Parameters in Arduino IDE:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 - Card: "WEMOS D1 Mini Lite"
-- Flash Size: "1M (512K SPIFFS)"
+- Flash Size: "1M (512K FS)"
 - CPU Frequency: "80 Mhz"
 
 Power:

doc/esp8266wifi/bearssl-client-secure-class.rst

@@ -102,9 +102,9 @@ The web browser you're using to read this document keeps a list of 100s of certi
 
 In many cases your application will know the specific CA it needs to validate web or MQTT servers against (often just a single, self-signing CA private to your institution).  Simply load your private CA in a `BearSSL::X509List` and use that as your trust anchor.
 
-However, there are cases where you will not know beforehand which CA you will need (i.e. a user enters a website through a keypad), and you need to keep the list of CAs just like your web browser.  In those cases, you need to generate a certificate bundle on the PC while compiling your application, upload the `certs.ar` bundle to SPIFFS or SD when uploading your application binary, and pass it to a `BearSSL::CertStore()` in order to validate TLS peers.
+However, there are cases where you will not know beforehand which CA you will need (i.e. a user enters a website through a keypad), and you need to keep the list of CAs just like your web browser.  In those cases, you need to generate a certificate bundle on the PC while compiling your application, upload the `certs.ar` bundle to LittleFS or SD when uploading your application binary, and pass it to a `BearSSL::CertStore()` in order to validate TLS peers.
 
-See the `BearSSL_CertStore` example for full details as the `BearSSL::CertStore` requires the creation of a cookie-cutter object for filesystem access (because the SD and SPIFFS filesystems are presently incompatible with each other).  At a high level in your `setup()` you will call `BearSSL::initCertStore()` on a global object, and then pass this global certificate store to `client.setCertStore(&gCA)` before every connection attempt to enable it as a validation option.
+See the `BearSSL_CertStore` example for full details.
 
 Supported Crypto
 ~~~~~~~~~~~~~~~~

doc/esp8266wifi/client-secure-class.rst

@@ -42,23 +42,24 @@ Load client certificate from file system.
 .. code:: cpp
 
     #include <FS.h>
+    #include <LittleFS.h>
     #include <ESP8266WiFi.h>
     #include <WiFiClientSecure.h>
 
-    const char* certyficateFile = "/client.cer";
+    const char* certificateFile = "/client.cer";
 
 *setup() or loop()*
 
 .. code:: cpp
 
-    if (!SPIFFS.begin()) 
+    if (!LittleFS.begin())
     {
       Serial.println("Failed to mount the file system");
       return;
     }
 
-    Serial.printf("Opening %s", certyficateFile);
-    File crtFile = SPIFFS.open(certyficateFile, "r");
+    Serial.printf("Opening %s", certificateFile);
+    File crtFile = LittleFS.open(certificateFile, "r");
     if (!crtFile)
     {
       Serial.println(" Failed!");
@@ -66,7 +67,7 @@ Load client certificate from file system.
 
     WiFiClientSecure client;
 
-    Serial.print("Loading %s", certyficateFile);
+    Serial.print("Loading %s", certificateFile);
     if (!client.loadCertificate(crtFile))
     {
       Serial.println(" Failed!");

doc/faq/readme.rst

@@ -79,7 +79,7 @@ perform. It is not listed among libraries verified to work with ESP8266.
 
 `Read more <a03-library-does-not-work.rst>`__.
 
-In the IDE, for ESP-12E that has 4M flash, I can choose 4M (1M SPIFFS) or 4M (3M SPIFFS). No matter what I select, the IDE tells me the maximum code space is about 1M. Where does my flash go?
+In the IDE, for ESP-12E that has 4M flash, I can choose 4M (1M FS) or 4M (3M FS). No matter what I select, the IDE tells me the maximum code space is about 1M. Where does my flash go?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The reason we cannot have more than 1MB of code in flash has to do with
@@ -90,7 +90,7 @@ total, but switching such "banks" on the fly is not easy and efficient,
 so we don't bother doing that. Besides, no one has so far complained
 about 1MB of code space being insufficient for practical purposes.
 
-The option to choose 3M or 1M SPIFFS is to optimize the upload time.
+The option to choose 3M or 1M filesystem is to optimize the upload time.
 Uploading 3MB takes a long time so sometimes you can just use 1MB. Other
 2MB of flash can still be used with ``ESP.flashRead`` and
 ``ESP.flashWrite`` APIs if necessary.

doc/filesystem.rst

@@ -63,6 +63,16 @@ following include to the sketch:
 
     #include "FS.h"
 
+SPIFFS Deprecation Warning
+--------------------------
+
+SPIFFS is currently deprecated and may be removed in future releases of
+the core.  Please consider moving your code to LittleFS.  SPIFFS is not
+actively supported anymore by the upstream developer, while LittleFS is
+under active development, supports real directories, and is many times
+faster for most operations.
+
+
 SPIFFS and LittleFS
 -------------------
 

doc/installing.rst

@@ -244,6 +244,6 @@ BeagleBone, CubieBoard).
 - `What is PlatformIO? <https://docs.platformio.org/en/latest/what-is-platformio.html?utm_source=arduino-esp8266>`__
 - `PlatformIO IDE <https://platformio.org/platformio-ide?utm_source=arduino-esp8266>`__
 - `PlatformIO Core <https://docs.platformio.org/en/latest/core.html?utm_source=arduino-esp8266>`__ (command line tool)
-- `Advanced usage <https://docs.platformio.org/en/latest/platforms/espressif8266.html?utm_source=arduino-esp8266>`__ - custom settings, uploading to SPIFFS, Over-the-Air (OTA), staging version
+- `Advanced usage <https://docs.platformio.org/en/latest/platforms/espressif8266.html?utm_source=arduino-esp8266>`__ - custom settings, uploading to LittleFS, Over-the-Air (OTA), staging version
 - `Integration with Cloud and Standalone IDEs <https://docs.platformio.org/en/latest/ide.html?utm_source=arduino-esp8266>`__ - Cloud9, Codeanywhere, Eclipse Che (Codenvy), Atom, CLion, Eclipse, Emacs, NetBeans, Qt Creator, Sublime Text, VIM, Visual Studio, and VSCode
 - `Project Examples <https://docs.platformio.org/en/latest/platforms/espressif8266.html?utm_source=arduino-esp8266#examples>`__

doc/libraries.rst

@@ -25,7 +25,7 @@ This is a bit different from standard EEPROM class. You need to call ``EEPROM.be
 
 ``EEPROM.write`` does not write to flash immediately, instead you must call ``EEPROM.commit()`` whenever you wish to save changes to flash. ``EEPROM.end()`` will also commit, and will release the RAM copy of EEPROM contents.
 
-EEPROM library uses one sector of flash located just after the SPIFFS.
+EEPROM library uses one sector of flash located just after the embedded filesystem.
 
 `Three examples <https://github.com/esp8266/Arduino/tree/master/libraries/EEPROM>`__  included.
 

doc/ota_updates/readme.rst

@@ -360,7 +360,7 @@ If this is the case, then most likely ESP module has not been reset after initia
 The most common causes of OTA failure are as follows:
 
 - not enough physical memory on the chip (e.g. ESP01 with 512K flash memory is not enough for OTA).
-- too much memory declared for SPIFFS so new sketch will not fit between existing sketch and SPIFFS – see `Update process - memory view <#update-process-memory-view>`__.
+- too much memory declared for the filesystem so new sketch will not fit between existing sketch and the filesystem – see `Update process - memory view <#update-process-memory-view>`__.
 - too little memory declared in Arduino IDE for your selected board (i.e. less than physical size).
 - not resetting the ESP module after initial upload using serial port.