The task runner

lib/tasks.sh is the qgis-dev command. It is the single source of behaviour behind three front-ends, so nothing can drift between how the editor, a terminal, and CI build QGIS.

One implementation, three doors

• Neovim (overlay/nvim.lua) maps <leader>p… to vim.system calls that run qgis-dev <cmd> asynchronously and parse failures into the quickfix list.
• nix run .#<cmd> enters the devshell and calls the same binary.
• The terminal calls qgis-dev directly inside the devshell.

The flake installs tasks.sh into the nix store as qgis-dev (install -Dm755), so the front-ends all execute identical bytes.

Anatomy of a call

init() resolves four locations from the current directory: ROOT (the checkout, via git rev-parse), SIDECAR (from .dev-env/sidecar or the .envrc symlink target), BUILD (ROOT/build) and STATE (ROOT/.dev-env). Read-only commands that don't need a checkout — stats, report, perf — deliberately skip init (it dies outside a checkout, and die calls exit, which || true cannot catch).

Commands then compose smaller helpers: cmd_build snapshots ccache counters around ninja and appends a row to the log; cmd_configure sources the active profiles/*.profile fragment onto a CMAKE_ARGS array; cmd_report runs an awk pass to produce clean data + summary scalars and drives report.gnuplot.

Where behaviour lives

Concern	File (read at runtime from SIDECAR)
Build presets	profiles/{debug,minimal,release,asan-ubsan}.profile
Valgrind noise filters	suppressions/{qt6,glib,python}.supp
Infographic template	lib/report.gnuplot (also exported as a store path)
Activation banner	lib/shell-motd.sh

Because these are read live from the sidecar, editing a profile or the banner takes effect immediately — no devshell rebuild. Editing tasks.sh does need a reload, since it is baked into the qgis-dev binary; the .envrc therefore watches it.