build a CIRCUITPY_ERASER variant

main.c

@@ -554,6 +554,15 @@ int __attribute__((used)) main(void) {
 
     stack_init();
 
+    // If this is a CIRCUITPY eraser build, just erase and reformat the filesystem,
+    // and that's it. Don't print anything, etc. Just erase and wait.
+    #if CIRCUITPY_ERASER
+    new_status_color(RED);
+    filesystem_init(true, true);
+    new_status_color(BLUE);
+    while(1) { }
+    #endif
+
     // Create a new filesystem only if we're not in a safe mode.
     // A power brownout here could make it appear as if there's
     // no SPI flash filesystem, and we might erase the existing one.

py/circuitpy_mpconfig.mk

@@ -26,6 +26,11 @@
 # Boards default to all modules enabled (with exceptions)
 # Manually disable by overriding in #mpconfigboard.mk
 
+# True if this is a special build that does nothing but erase and
+# reformat CIRCUITPY.
+CIRCUITPY_ERASER ?= 0
+CFLAGS += -DCIRCUITPY_ERASER=$(CIRCUITPY_ERASER)
+
 # Smaller builds can be forced for resource constrained chips (typically SAMD21s
 # without external flash) by setting CIRCUITPY_FULL_BUILD=0. Avoid using this
 # for merely incomplete ports, as it changes settings in other files.

tools/build_release_files.py

@@ -13,7 +13,7 @@
 import time
 
 for port in build_info.SUPPORTED_PORTS:
-    result = subprocess.run("rm -rf ../ports/{port}/build*".format(port=port), shell=True)
+    result = subprocess.run(f"rm -rf ../ports/{port}/build*", shell=True)
 
 PARALLEL = "-j 5"
 if "GITHUB_ACTION" in os.environ:
@@ -34,42 +34,41 @@
 
 exit_status = 0
 cores = multiprocessing.cpu_count()
-print("building boards with parallelism {}".format(cores))
+print(f"building boards with parallelism {cores}")
 for board in build_boards:
-    bin_directory = "../bin/{}/".format(board)
+    bin_directory = f"../bin/{board}/"
     os.makedirs(bin_directory, exist_ok=True)
     board_info = all_boards[board]
+    port = board_info["port"]
 
-    for language in languages:
-        bin_directory = "../bin/{board}/{language}".format(board=board, language=language)
+    variants = [(language, language, "") for language in languages]
+    # Add non-language variant builds.
+    variants.append(("CIRCUITPY_ERASER", "en_US", "CIRCUITPY_ERASER=1"))
+
+    for (variant_name, language, settings) in variants:
+        bin_directory = f"../bin/{board}/{variant_name}"
         os.makedirs(bin_directory, exist_ok=True)
         start_time = time.monotonic()
 
-        # Normally different language builds are all done based on the same set of compiled sources.
+        # Normally different language/variant builds are all done based on the same set of compiled sources.
         # But sometimes a particular language needs to be built from scratch, if, for instance,
         # CFLAGS_INLINE_LIMIT is set for a particular language to make it fit.
         clean_build_check_result = subprocess.run(
-            "make -C ../ports/{port} TRANSLATION={language} BOARD={board} check-release-needs-clean-build -j {cores} | fgrep 'RELEASE_NEEDS_CLEAN_BUILD = 1'".format(
-                port=board_info["port"], language=language, board=board, cores=cores
-            ),
+            f"make -C ../ports/{port} TRANSLATION={language} BOARD={board} {settings} check-release-needs-clean-build -j {cores} | fgrep 'RELEASE_NEEDS_CLEAN_BUILD = 1'",
             shell=True,
             stdout=subprocess.PIPE,
             stderr=subprocess.STDOUT,
         )
-        clean_build = clean_build_check_result.returncode == 0
 
-        build_dir = "build-{board}".format(board=board)
+        # If settings is non-empty, assume we need a clean build.
+        clean_build = clean_build_check_result.returncode == 0 or settings
+
+        build_dir = f"build-{board}"
         if clean_build:
-            build_dir += "-{language}".format(language=language)
+            build_dir += f"-{variant_name}"
 
         make_result = subprocess.run(
-            "make -C ../ports/{port} TRANSLATION={language} BOARD={board} BUILD={build} -j {cores}".format(
-                port=board_info["port"],
-                language=language,
-                board=board,
-                build=build_dir,
-                cores=cores,
-            ),
+            f"make -C ../ports/{port} TRANSLATION={language} BOARD={board} {settings} BUILD={build_dir} -j {cores}",
             shell=True,
             stdout=subprocess.PIPE,
             stderr=subprocess.STDOUT,
@@ -84,33 +83,24 @@
         other_output = ""
 
         for extension in board_info["extensions"]:
-            temp_filename = "../ports/{port}/{build}/firmware.{extension}".format(
-                port=board_info["port"], build=build_dir, extension=extension
-            )
+            temp_filename = f"../ports/{port}/{build_dir}/firmware.{extension}"
             for alias in board_info["aliases"] + [board]:
-                bin_directory = "../bin/{alias}/{language}".format(alias=alias, language=language)
+                bin_directory = f"../bin/{alias}/{variant_name}"
                 os.makedirs(bin_directory, exist_ok=True)
                 final_filename = (
-                    "adafruit-circuitpython-{alias}-{language}-{version}.{extension}".format(
-                        alias=alias, language=language, version=version, extension=extension
-                    )
+                    f"adafruit-circuitpython-{alias}-{variant_name}-{version}.{extension}"
                 )
                 final_filename = os.path.join(bin_directory, final_filename)
                 try:
                     shutil.copyfile(temp_filename, final_filename)
                 except FileNotFoundError:
-                    other_output = "Cannot find file {}".format(temp_filename)
+                    other_output = f"Cannot find file {temp_filename}"
                     if exit_status == 0:
                         exit_status = 1
 
+        clean_build_str = " (clean_build)" if clean_build else ""
         print(
-            "Build {board} for {language}{clean_build} took {build_duration:.2f}s and {success}".format(
-                board=board,
-                language=language,
-                clean_build=(" (clean_build)" if clean_build else ""),
-                build_duration=build_duration,
-                success=success,
-            )
+            f"Build {board} for {variant_name}{clean_build_str} took {build_duration:.2f}s and {success}"
         )
 
         print(make_result.stdout.decode("utf-8"))