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Research whether PlatformIO __idedata / project metadata can support a scripted-project bridge #39
Description
Parent: #34
Problem
Before committing to full SCons compatibility, we should verify whether PlatformIO's existing metadata/export surfaces are rich enough to drive fbuild for scripted projects. If they are not, ?full support? likely means embedding or delegating to SCons/PlatformIO rather than merely importing resolved flags.
PlatformIO source evidence
DumpIntegrationData()exportsbuild_type, defines, includes,cc_flags,cxx_flags, tool paths, targets, and some extra flash image data:.cache/platformio-core/platformio/builder/tools/piointegration.py:141-173load_build_metadata()drives__idedataand optionally__debugto populateidedata.json:.cache/platformio-core/platformio/project/helpers.py:134-186builder/main.pywritesidedata.jsonduring integration dump:.cache/platformio-core/platformio/builder/main.py:214-227
Why this matters
If __idedata or pio project metadata fully captured the resolved build graph, fbuild could potentially import it and keep native compilation/linking. If it only captures editor-oriented data, then it is insufficient for a full bridge and option (3) becomes much more expensive.
Initial gaps already visible
- the integration dump exposes compile flags, but not a full resolved link command line
- it does not obviously export all library archives/order needed for final linking
- it does not capture action hooks / custom target behavior from scripts
- it is designed for IDE integration, not for faithfully replaying the full PlatformIO build graph
Requested change
Do a focused feasibility spike on a ?metadata bridge? approach:
- Inventory exactly what
__idedata/pio project metadataexposes - Compare that to what fbuild needs for native compile/link/deploy parity
- Identify hard blockers for scripted projects
- Recommend one of:
- viable bridge for a narrow subset
- useful only for editor/intellisense parity
- insufficient for build parity, so full support implies real SCons/PlatformIO delegation
Acceptance criteria
- The outcome is a short design note or issue comment on platformio.ini advanced build configurations are not yet compatible with PlatformIO/SCons flag workflows #34
- The note explicitly says whether metadata import can underpin option (3)
- Missing data required for native parity is enumerated concretely
Activity
zackees commentedon Apr 17, 2026
__idedata/pio project metadatais good for IDE-style snapshots, but it is not enough to underpin a general scripted-project bridge.PlatformIO's integration dump serializes resolved editor-facing data such as
build_type, defines, include paths,cc_flags,cxx_flags, tool paths, targets, and some extra flash image data (.platformio/penv/Lib/site-packages/platformio/builder/tools/piointegration.py,.platformio/penv/Lib/site-packages/platformio/builder/main.py,.platformio/penv/Lib/site-packages/platformio/project/helpers.py). It does not expose a resolved link command, archive ordering, custom target actions, or script provenance.On the fbuild side, native startup currently consumes config, board data, compile flags, and a limited
extra_scriptsoverlay (crates/fbuild-build/src/pipeline.rs,crates/fbuild-build/src/script_runtime.rs,crates/fbuild-config/src/ini_parser.rs). Metadata alone is therefore insufficient to replay arbitrary scripted builds. The narrow viable subset is projects whose scripts collapse entirely into final env mutations already reflected in metadata; anything that generates sources, changes link order, or adds custom SCons/upload behavior still needs real PlatformIO/SCons delegation.I also spot-checked this on a local PlatformIO project with
pio project metadata --json-output -e uno: the payload included compile flags, include roots, tool paths, and target names likeuploadandsize, but not an executable build graph or custom action data.Conclusion: metadata import may be useful for editor/intellisense parity or a very narrow flag-only bridge, but it is not sufficient as the foundation for general scripted-project parity.