Add support for "Build Middlewares"

HISTORY.rst

@@ -18,6 +18,7 @@ PlatformIO Core 4.0
   - Unused variables or functions
   - Out of scope memory usage.
 
+* Added support for `Build Middlewares <http://docs.platformio.org/page/projectconf/advanced_scripting.html#build-middlewares>`__: configure custom build flags per specific file, skip any build nodes from a framework, replace build file with another on-the-fly, etc.
 * Extend project environment configuration in "platformio.ini" with other sections using a new `extends <http://docs.platformio.org/page/projectconf/section_env_advanced.html#extends>`__ option (`issue #2953 <https://github.com/platformio/platformio-core/issues/2953>`_)
 * Generate ``.ccls`` LSP file for `Emacs <https://docs.platformio.org/page/ide/emacs.html>`__ cross references, hierarchies, completion and semantic highlighting
 * Added ``--no-ansi`` flag for `PIO Core <http://docs.platformio.org/page/userguide/index.html>`__ to disable ANSI control characters

platformio/builder/tools/platformio.py

@@ -14,10 +14,12 @@
 
 from __future__ import absolute_import
 
+import fnmatch
 import os
 import sys
 
 from SCons import Builder, Util  # pylint: disable=import-error
+from SCons.Node import FS  # pylint: disable=import-error
 from SCons.Script import COMMAND_LINE_TARGETS  # pylint: disable=import-error
 from SCons.Script import AlwaysBuild  # pylint: disable=import-error
 from SCons.Script import DefaultEnvironment  # pylint: disable=import-error
@@ -244,7 +246,9 @@ def MatchSourceFiles(env, src_dir, src_filter=None):
     )
 
 
-def CollectBuildFiles(env, variant_dir, src_dir, src_filter=None, duplicate=False):
+def CollectBuildFiles(
+    env, variant_dir, src_dir, src_filter=None, duplicate=False
+):  # pylint: disable=too-many-locals
     sources = []
     variants = []
 
@@ -264,9 +268,24 @@ def CollectBuildFiles(env, variant_dir, src_dir, src_filter=None, duplicate=Fals
         if fs.path_endswith_ext(item, SRC_BUILD_EXT):
             sources.append(env.File(os.path.join(_var_dir, os.path.basename(item))))
 
+    for callback, pattern in env.get("__PIO_BUILD_MIDDLEWARES", []):
+        tmp = []
+        for node in sources:
+            if pattern and not fnmatch.fnmatch(node.get_path(), pattern):
+                tmp.append(node)
+                continue
+            n = callback(node)
+            if n:
+                tmp.append(n)
+        sources = tmp
+
     return sources
 
 
+def AddBuildMiddleware(env, callback, pattern=None):
+    env.Append(__PIO_BUILD_MIDDLEWARES=[(callback, pattern)])
+
+
 def BuildFrameworks(env, frameworks):
     if not frameworks:
         return
@@ -309,7 +328,11 @@ def BuildLibrary(env, variant_dir, src_dir, src_filter=None):
 
 def BuildSources(env, variant_dir, src_dir, src_filter=None):
     nodes = env.CollectBuildFiles(variant_dir, src_dir, src_filter)
-    DefaultEnvironment().Append(PIOBUILDFILES=[env.Object(node) for node in nodes])
+    DefaultEnvironment().Append(
+        PIOBUILDFILES=[
+            env.Object(node) if isinstance(node, FS.File) else node for node in nodes
+        ]
+    )
 
 
 def exists(_):
@@ -323,6 +346,7 @@ def generate(env):
     env.AddMethod(ProcessUnFlags)
     env.AddMethod(MatchSourceFiles)
     env.AddMethod(CollectBuildFiles)
+    env.AddMethod(AddBuildMiddleware)
     env.AddMethod(BuildFrameworks)
     env.AddMethod(BuildLibrary)
     env.AddMethod(BuildSources)

platformio/commands/check/command.py

@@ -165,7 +165,7 @@ def results_to_json(raw):
             {
                 "ignored": item.get("succeeded") is None,
                 "succeeded": bool(item.get("succeeded")),
-                "defects": [d.as_dict() for d in item.get("defects", [])]
+                "defects": [d.as_dict() for d in item.get("defects", [])],
             }
         )
         results.append(item)