sx-git Phase 2: refs — branches/tags/HEAD over persist kv, CAS + reflog (TDD)

Ref value = {:cid} | {:symref}; atomic moves via persist/kv-cas old-value
expect, create-only branches via kv-put-new; bounded symref resolution;
per-ref append-only reflog on the persist log facet. 38/38, total 76/76.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
2026-07-03 12:03:36 +00:00
parent 9a85b52d1a
commit 74c2521926
5 changed files with 413 additions and 5 deletions

View File

@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
exit 1 exit 1
fi fi
SUITES=(object) SUITES=(object ref)
OUT_JSON="lib/git/scoreboard.json" OUT_JSON="lib/git/scoreboard.json"
OUT_MD="lib/git/scoreboard.md" OUT_MD="lib/git/scoreboard.md"
@@ -33,6 +33,7 @@ run_suite() {
(load "lib/persist/kv.sx") (load "lib/persist/kv.sx")
(load "lib/artdag/dag.sx") (load "lib/artdag/dag.sx")
(load "lib/git/object.sx") (load "lib/git/object.sx")
(load "lib/git/ref.sx")
(epoch 2) (epoch 2)
(eval "(define git-test-pass 0)") (eval "(define git-test-pass 0)")
(eval "(define git-test-fail 0)") (eval "(define git-test-fail 0)")

197
lib/git/ref.sx Normal file
View File

@@ -0,0 +1,197 @@
; lib/git/ref.sx — sx-git Phase 2: refs as name -> cid over persist kv.
; A ref value is {:cid cid} (direct) or {:symref name} (symbolic). Atomic
; update = persist/kv-cas (old-value expect); create-only = kv-put-new.
; Every direct-ref move is recorded in an append-only reflog stream
; (persist log facet), one stream per ref name.
; Requires: lib/git/object.sx (repo handle), lib/persist/kv.sx, log.sx.
(define git/ref-key (fn (repo name) (str (get repo :prefix) "/ref/" name)))
(define
git/reflog-stream
(fn (repo name) (str (get repo :prefix) "/reflog/" name)))
(define
git/reflog-record!
(fn
(repo name old new)
(persist/append
(get repo :db)
(git/reflog-stream repo name)
"ref-update"
0
{:new new :old old})))
; ---- raw ref values ----
(define
git/ref-read
(fn (repo name) (persist/kv-get (get repo :db) (git/ref-key repo name))))
(define git/symref? (fn (v) (and (dict? v) (has-key? v :symref))))
; direct cid or nil — does NOT follow symrefs
(define
git/ref-get
(fn
(repo name)
(let ((v (git/ref-read repo name))) (if (dict? v) (get v :cid) nil))))
; ---- writes ----
(define
git/ref-set!
(fn
(repo name cid)
(let
((old (git/ref-get repo name)))
(begin
(persist/kv-put (get repo :db) (git/ref-key repo name) {:cid cid})
(git/reflog-record! repo name old cid)
cid))))
(define
git/symref-set!
(fn
(repo name target)
(begin
(persist/kv-put (get repo :db) (git/ref-key repo name) {:symref target})
target)))
(define
git/ref-delete!
(fn
(repo name)
(persist/kv-delete (get repo :db) (git/ref-key repo name))))
; ---- resolution (symref chains, bounded) ----
(define
git/ref-resolve-n
(fn
(repo name depth)
(if
(<= depth 0)
nil
(let
((v (git/ref-read repo name)))
(cond
((git/symref? v)
(git/ref-resolve-n repo (get v :symref) (- depth 1)))
((dict? v) (get v :cid))
(else nil))))))
(define
git/ref-resolve
(fn (repo name) (git/ref-resolve-n repo name 10)))
; ---- atomic update: expected old cid (nil = must not exist) ----
(define
git/ref-cas!
(fn
(repo name expected new)
(let
((res (persist/kv-cas (get repo :db) (git/ref-key repo name) (if (equal? expected nil) nil {:cid expected}) {:cid new})))
(if
(and (dict? res) (has-key? res :conflict))
{:actual (if (dict? (get res :actual)) (get (get res :actual) :cid) nil) :conflict true}
(begin (git/reflog-record! repo name expected new) new)))))
; ---- listing ----
(define
git/ref-names
(fn
(repo)
(let
((pfx (str (get repo :prefix) "/ref/")))
(artdag/sort-strings
(map
(fn (k) (substring k (string-length pfx) (string-length k)))
(filter
(fn (k) (starts-with? k pfx))
(persist/kv-keys (get repo :db))))))))
(define
git/refs-under
(fn
(repo group)
(map
(fn (n) (substring n (string-length group) (string-length n)))
(filter (fn (n) (starts-with? n group)) (git/ref-names repo)))))
; ---- branches ----
(define git/branch-ref (fn (name) (str "heads/" name)))
(define
git/branch-set!
(fn (repo name cid) (git/ref-set! repo (git/branch-ref name) cid)))
(define
git/branch-get
(fn (repo name) (git/ref-get repo (git/branch-ref name))))
(define
git/branch-cas!
(fn
(repo name expected new)
(git/ref-cas! repo (git/branch-ref name) expected new)))
(define
git/branch-delete!
(fn (repo name) (git/ref-delete! repo (git/branch-ref name))))
(define git/branches (fn (repo) (git/refs-under repo "heads/")))
; create-only: conflict if the branch already exists
(define
git/branch-create!
(fn
(repo name cid)
(let
((res (persist/kv-put-new (get repo :db) (git/ref-key repo (git/branch-ref name)) {:cid cid})))
(if
(and (dict? res) (has-key? res :conflict))
{:actual (get (get res :actual) :cid) :conflict true}
(begin (git/reflog-record! repo (git/branch-ref name) nil cid) cid)))))
; ---- lightweight tag refs (annotated tag objects live in the object store) ----
(define git/tag-refname (fn (name) (str "tags/" name)))
(define
git/tag-set!
(fn (repo name cid) (git/ref-set! repo (git/tag-refname name) cid)))
(define
git/tag-get
(fn (repo name) (git/ref-get repo (git/tag-refname name))))
(define git/tag-names (fn (repo) (git/refs-under repo "tags/")))
; ---- HEAD ----
(define
git/head-set!
(fn (repo branch) (git/symref-set! repo "HEAD" (git/branch-ref branch))))
(define
git/head-detach!
(fn
(repo cid)
(begin
(persist/kv-put (get repo :db) (git/ref-key repo "HEAD") {:cid cid})
cid)))
(define git/head (fn (repo) (git/ref-resolve repo "HEAD")))
; branch ref name HEAD points at, or nil when detached/unset
(define
git/head-target
(fn
(repo)
(let
((v (git/ref-read repo "HEAD")))
(if (git/symref? v) (get v :symref) nil))))
(define
git/detached?
(fn
(repo)
(let
((v (git/ref-read repo "HEAD")))
(and (dict? v) (has-key? v :cid)))))
; ---- reflog: oldest-first list of {:old :new} ----
(define
git/reflog
(fn
(repo name)
(map
(fn (e) (persist/event-data e))
(persist/read (get repo :db) (git/reflog-stream repo name)))))

View File

@@ -1,8 +1,9 @@
{ {
"suites": { "suites": {
"object": {"pass": 38, "fail": 0} "object": {"pass": 38, "fail": 0},
"ref": {"pass": 38, "fail": 0}
}, },
"total_pass": 38, "total_pass": 76,
"total_fail": 0, "total_fail": 0,
"total": 38 "total": 76
} }

View File

@@ -5,4 +5,5 @@ _Generated by `lib/git/conformance.sh`_
| Suite | Pass | Fail | Total | | Suite | Pass | Fail | Total |
|-------|-----:|-----:|------:| |-------|-----:|-----:|------:|
| object | 38 | 0 | 38 | | object | 38 | 0 | 38 |
| **Total** | **38** | **0** | **38** | | ref | 38 | 0 | 38 |
| **Total** | **76** | **0** | **76** |

208
lib/git/tests/ref.sx Normal file
View File

@@ -0,0 +1,208 @@
; Phase 2 — ref: branches/tags/HEAD as name -> cid over persist kv, symbolic
; refs, CAS updates with old-value expect, reflog.
(define grt-db (persist/mem-backend))
(define grt (git/repo grt-db))
(define grt-c1 (git/write-blob grt "one"))
(define grt-c2 (git/write-blob grt "two"))
(define grt-c3 (git/write-blob grt "three"))
; ---- direct refs ----
(git-test "ref-get on unset ref is nil" (git/ref-get grt "heads/none") nil)
(git-test
"ref-set! returns the cid"
(git/ref-set! grt "heads/main" grt-c1)
grt-c1)
(git-test "ref-get reads it back" (git/ref-get grt "heads/main") grt-c1)
(git-test
"ref-resolve on a direct ref"
(git/ref-resolve grt "heads/main")
grt-c1)
(git-test
"ref-resolve on missing ref is nil"
(git/ref-resolve grt "nope")
nil)
; ---- symbolic refs ----
(git-test
"symref resolves through its target"
(begin
(git/symref-set! grt "HEAD" "heads/main")
(git/ref-resolve grt "HEAD"))
grt-c1)
(git-test
"symref chain resolves"
(begin
(git/symref-set! grt "INDIRECT" "HEAD")
(git/ref-resolve grt "INDIRECT"))
grt-c1)
(git-test
"symref cycle is bounded, resolves nil"
(begin
(git/symref-set! grt "LOOPA" "LOOPB")
(git/symref-set! grt "LOOPB" "LOOPA")
(git/ref-resolve grt "LOOPA"))
nil)
(git-test "ref-get does not follow a symref" (git/ref-get grt "HEAD") nil)
(git-test
"symref? on a raw symref value"
(git/symref? (git/ref-read grt "HEAD"))
true)
; ---- CAS ----
(git-test
"cas create (expected nil) succeeds"
(git/ref-cas! grt "heads/dev" nil grt-c1)
grt-c1)
(git-test
"cas create conflicts when the ref exists"
(get (git/ref-cas! grt "heads/dev" nil grt-c2) :conflict)
true)
(git-test
"cas conflict reports the actual cid"
(get (git/ref-cas! grt "heads/dev" grt-c3 grt-c2) :actual)
grt-c1)
(git-test
"cas conflict leaves the ref unchanged"
(git/ref-get grt "heads/dev")
grt-c1)
(git-test
"cas with the right expected value moves the ref"
(git/ref-cas! grt "heads/dev" grt-c1 grt-c2)
grt-c2)
(git-test "cas move is visible" (git/ref-get grt "heads/dev") grt-c2)
; ---- delete ----
(git-test
"ref-delete! removes the ref"
(begin
(git/ref-set! grt "heads/tmp" grt-c1)
(git/ref-delete! grt "heads/tmp")
(git/ref-get grt "heads/tmp"))
nil)
; ---- branch conveniences ----
(git-test
"branch-create! returns the cid"
(git/branch-create! grt "feature" grt-c1)
grt-c1)
(git-test
"branch-create! conflicts on an existing branch"
(get (git/branch-create! grt "feature" grt-c2) :conflict)
true)
(git-test "branch-get" (git/branch-get grt "feature") grt-c1)
(git-test
"branch-cas! moves the branch"
(git/branch-cas! grt "feature" grt-c1 grt-c2)
grt-c2)
(git-test
"branch-set! moves unconditionally"
(git/branch-set! grt "feature" grt-c3)
grt-c3)
(git-test
"branch-delete! removes it"
(begin (git/branch-delete! grt "feature") (git/branch-get grt "feature"))
nil)
; ---- listing ----
(git-test
"branches are listed sorted, tags and HEAD excluded"
(let
((db (persist/mem-backend)))
(let
((r (git/repo db)))
(begin
(git/branch-set! r "zeta" "sx1:z")
(git/branch-set! r "alpha" "sx1:a")
(git/tag-set! r "v1" "sx1:t")
(git/head-set! r "alpha")
(= (git/branches r) (list "alpha" "zeta")))))
true)
(git-test
"tag-names lists tag refs"
(let
((db (persist/mem-backend)))
(let
((r (git/repo db)))
(begin
(git/tag-set! r "v2" "sx1:t2")
(git/tag-set! r "v1" "sx1:t1")
(= (git/tag-names r) (list "v1" "v2")))))
true)
(git-test
"tag-get reads a tag ref"
(begin (git/tag-set! grt "v1" grt-c1) (git/tag-get grt "v1"))
grt-c1)
; ---- HEAD ----
(git-test
"head resolves through the current branch"
(begin
(git/branch-set! grt "main" grt-c2)
(git/head-set! grt "main")
(git/head grt))
grt-c2)
(git-test
"moving the branch moves head"
(begin (git/branch-set! grt "main" grt-c3) (git/head grt))
grt-c3)
(git-test
"head-target names the branch ref"
(git/head-target grt)
"heads/main")
(git-test "detached? false on a symref HEAD" (git/detached? grt) false)
(git-test
"head-detach! pins a cid"
(begin (git/head-detach! grt grt-c1) (git/head grt))
grt-c1)
(git-test "detached? true after detach" (git/detached? grt) true)
(git-test "head-target nil when detached" (git/head-target grt) nil)
; ---- reflog ----
(git-test
"reflog of an untouched ref is empty"
(= (git/reflog grt "heads/quiet") (list))
true)
(git-test
"reflog records create and moves oldest-first"
(let
((db (persist/mem-backend)))
(let
((r (git/repo db)))
(begin
(git/ref-set! r "heads/x" "sx1:a")
(git/ref-set! r "heads/x" "sx1:b")
(git/ref-cas! r "heads/x" "sx1:b" "sx1:c")
(= (git/reflog r "heads/x") (list {:new "sx1:a" :old nil} {:new "sx1:b" :old "sx1:a"} {:new "sx1:c" :old "sx1:b"})))))
true)
(git-test
"branch-create! writes the first reflog entry"
(let
((db (persist/mem-backend)))
(let
((r (git/repo db)))
(begin
(git/branch-create! r "b" "sx1:a")
(= (git/reflog r "heads/b") (list {:new "sx1:a" :old nil})))))
true)
(git-test
"failed cas leaves no reflog entry"
(let
((db (persist/mem-backend)))
(let
((r (git/repo db)))
(begin
(git/ref-set! r "heads/x" "sx1:a")
(git/ref-cas! r "heads/x" "sx1:wrong" "sx1:b")
(len (git/reflog r "heads/x")))))
1)
; ---- namespacing ----
(git-test
"refs are invisible across repo namespaces"
(let
((db (persist/mem-backend)))
(begin
(git/branch-set! (git/repo-named db "a") "main" "sx1:a")
(git/branch-get (git/repo-named db "b") "main")))
nil)