repo size: ~208 MB of .zig-cache-local build artifacts are still in git history (GitHub reports ~90 MB) #767

Summary

The repository weighs ~90 MB on GitHub (size = 92,650 KB via the API) even though the current HEAD tree is only 3.58 MB of content — and 2.85 MB of that is assets/logo.png. Basically all of the weight lives in git history, not in the current source: build artifacts from .zig-cache-local/ and .zig-cache-local2/ were committed at some point and, although the files were later deleted, the blobs remain in history.

Evidence

Measured on main:

So ~208 MB of history content is Zig build cache, while the checked-out sources are under a megabyte.

Largest single blobs in history:

9,134,656  .zig-cache-local/o/40435bca1bddd9dafc626fd817bd6ca3/build_zcu.o
5,257,624  .zig-cache-local/o/40435bca1bddd9dafc626fd817bd6ca3/build
3,591,464  .zig-cache-local/o/ee904ac84d4097604e4ec01a334e3aae/test_zcu.o
3,562,808  .zig-cache-local/o/63562846be42afb502b9dcffbb39fb2e/test_zcu.o
3,479,416  .zig-cache-local2/o/06f1f62c188b4fa32d663295a4002a2d/test_zcu.o
3,479,416  .zig-cache-local/o/0e8c9548db5580712ab9efbee53d0b26/test_zcu.o

Only 4 commits ever touched these paths. They were added by the orchestration/runtime commits and removed by 2200d0a ("chore: remove tracked junk files, update gitignore") — but deleting the files does not shrink history, so every clone still downloads them. .zig-cache-local/, .zig-cache-local2/ and zig-out/ are all in .gitignore today, so this is history-only, not an ongoing regression.

Impact

• Every clone/fetch pulls tens of MB of dead build cache; packfile download dominates first-time setup and CI checkout.
• GitHub repo size and local .git stay inflated (~49 MB packed after compression, ~90 MB as reported by GitHub).
• assets/logo.png at 2.85 MB is 80% of the current tree and also ships as an asset.

Suggested fix

1. Rewrite history to drop the cache directories, e.g. git filter-repo --path .zig-cache-local/ --path .zig-cache-local2/ --invert-paths (or BFG), then force-push main and ask forks to re-clone.
2. In the same pass, consider shrinking assets/logo.png (2.85 MB -> a few hundred KB is achievable with lossless re-compression or a resized variant).
3. Keep the existing .gitignore entries so it cannot recur, and optionally add a CI guard that fails if a tracked path matches .zig-cache* or zig-out/.
4. After the rewrite, verify with gh api repos/justrach/codedb --jq .size and a fresh bare clone that the report drops from ~90 MB toward the ~1 MB of real source.