The state index in the benchmarks, and the import at scale 60622d23b9e4

### Git import at scale (2026-09-30, oxygen#25)

An imported commit cost what the whole tree is: `git ls-tree` of every

path, a tree view worked out again, every path compared, and every

changed file rendered from its whole history. Phases timed over the

first 5 000 vscode commits (`OXY_TIMINGS`, repeated phases summed) led

the work, one cost at a time:

| Change | 5 000 commits |

|---|---:|

| Before | 312 s |

| Each commit's tree is its parent's plus the diff, from one `git diff-tree --stdin` | 245 s |

| A parent not kept has its tree listed, so its child renders only what changed | 225 s |

| An ordinary commit is built from the paths it changes alone | 178 s |

| The diff sets aside lines found on one side only, as Git's xdiff does | 91 s |

| It diffs from the base's rendering rather than rendering again | 81 s |

| Tree views updated in place; merges add the other side without text | 56 s |

| File graphs keep their order as edits splice it | 38.8 s |

Twenty text diffs took 92 of the 103 s the builder spent: files

rewritten whole (line endings changed), on which Myers' algorithm is

quadratic. Rendering a long-lived file walked every line it ever had;

it now follows its live lines. Every step verified all 5 000 commits

(13.4 million files) clean.

| vscode slice | Before | After |

|---|---:|---:|

| 5 000 commits | 312 s, 2.1 GB | 38.8 s, 1.5 GB |

| 20 000 commits | 4 530 s, 6.7 GB | 925 s, 6.4 GB |

### A state index for the working copy's base (2026-09-30, oxygen#41)

A snapshot replayed the base's history (0.70 s) and worked out its tree

view (0.31 s) every time. Each workspace now keeps its base as a local

state index: change metadata, the view, the introducers, every file's

deferred history with its graph key, and the tree's maps, decoded only

when a command needs them. The index is hashed, and a test build checks

every read against a full load. The rest of a status that grew with

the tree now follows the change: the manifest is parsed once and

rewritten only when that helps; graph keys are looked up only for files

the manifest knows; and the change is built from the changed paths.

Linux tip, MAINTAINERS edited, oxy and Git alternating under the same

load (Earth at load average 4.5, other jobs running):

| | oxy (06:24) | oxy now | Git |

|---|---:|---:|---:|

| status | 3.32 s, 641 MB | 1.26 to 1.39 s, 370 MB | 0.26 to 0.29 s |

| diff | 2.93 s | 1.19 to 1.45 s | 0.16 to 0.25 s |

| status, clean | 0.68 to 0.76 s | 0.41 to 0.43 s | 0.26 to 0.32 s |