mapsize/DEVELOPMENT.md

Development

Requires Go (see go.mod). No CGO, no external tools.

make build      # bin/mapsize, bin/treegen
make test       # go test ./...
make race       # go test -race ./...
make vet fmt-check
make benchmark  # go test -bench
make fuzz       # short fuzz runs of snapshot / treemap / filter
make release    # release archives and packages in bin/release

Releasing

Example for 1.2.0; substitute the real version throughout.

1. Update the version in internal/brand/brand.go and docs/mapsize.1, and add a ## 1.2.0 section to CHANGELOG.md. Commit.
2. Tag and push:

   git tag -a v1.2.0 -m "mapsize 1.2.0"
   git push origin master v1.2.0
   

3. Build everything (archives, .deb/.rpm/.apk/Arch packages, SHA256SUMS into bin/release; the first run downloads nfpm):

   make release VERSION=v1.2.0
   

4. Publish the GitHub release with the changelog section as notes:

   awk '/^## 1.2.0/{f=1;next} /^## /{f=0} f' CHANGELOG.md > /tmp/notes.md
   gh release create v1.2.0 --title v1.2.0 --notes-file /tmp/notes.md bin/release/*
   

5. Update Homebrew. This needs the tag pushed (step 2), because it checksums GitHub's source tarball for that tag:

   make brew-formula VERSION=v1.2.0      # writes bin/homebrew/mapsize.rb
   git clone https://github.com/andydixon/homebrew-tap /tmp/tap
   cp bin/homebrew/mapsize.rb /tmp/tap/Formula/mapsize.rb
   git -C /tmp/tap commit -am "mapsize 1.2.0" && git -C /tmp/tap push
   

   Users get it with brew upgrade mapsize. Template: packaging/homebrew/mapsize.rb.in.

Always pass VERSION=: otherwise it comes from git describe, which only matches the tag when HEAD is exactly the tagged commit. make release and the Homebrew formula stamp the version into the binary; make build and go install use the value in brand.go, which is why step 1 updates it.

The snapshot format is stable at version 1: a format change must bump snapshot.Version and keep the reader for version 1.

Test data

treegen creates synthetic trees:

bin/treegen --out /tmp/t --directories 50000 --files 1000000 --max-depth 20 --sparse --unicode
bin/mapsize /tmp/t

Benchmarks

make benchmark                          # Go micro-benchmarks (layout, render, filter, scan)
scripts/bench-scan.sh /path 1 2 4 8     # wall time and peak RSS per worker count
sudo DROP_CACHES=1 scripts/bench-scan.sh /path   # cold-cache runs
MAPSIZE_MEM_ROOT=/path go test ./internal/scan -run TestMemoryPerNode -v

Paste results into PERFORMANCE.md with the machine description. Never edit numbers by hand.

Terminal restoration checks

MAPSIZE_DEBUG_PANIC=ui bin/mapsize .        # panics on the first key press
MAPSIZE_DEBUG_PANIC=scanner bin/mapsize /   # panics in a scanner goroutine
stty -a                                     # echo/icanon must be back on

Profiling

bin/mapsize --no-ui --cpuprofile cpu.prof --memprofile mem.prof /path
go tool pprof -http=: cpu.prof

--log FILE --log-level debug writes a log without disturbing the TUI. Paths are logged only at debug/trace level.

Layout

See ARCHITECTURE.md. Rules of thumb:

• internal/treemap and internal/filter must not import UI packages.
• Only internal/platform may contain OS-specific code (build tags).
• All strings derived from filenames go through textutil.Sanitize before reaching a terminal.