Model commit-writer admission refusals

.github/workflows/ci.yml

@@ -274,7 +274,7 @@ jobs:
           "$ROOT/target/release/claim_executor" --source-root "$ROOT/dag" --source-root "$ROOT/src/v2" --plan-entry src/v2/workflow/ci_floor_plan.dag --plan-function gunbc_ci_floor_plan --notice-title "v2 claim corpus"
           FLOOR_EXIT=$?
           ROOT=$(git rev-parse --show-toplevel 2>/dev/null || pwd)
-          CI_FLOOR_EXIT=$FLOOR_EXIT "$ROOT/target/release/gunbc" run --source-root dag --entry dag/tools/merge_admission_stamp.dag --function main
+          CI_FLOOR_EXIT=$FLOOR_EXIT "$ROOT/target/release/gunbc" run --source-root dag --source-root src/v2 --entry dag/tools/merge_admission_stamp.dag --function main
           STAMP_EXIT=$?
           if [ "$FLOOR_EXIT" -ne 0 ]; then exit "$FLOOR_EXIT"; fi
           exit "$STAMP_EXIT"
@@ -288,7 +288,7 @@ jobs:
         timeout-minutes: 5
       - name: Merge-admission gate (receipt required; freshness block held until GatingEnforced)
         run: |
-          'git' 'fetch' '--no-tags' 'origin' 'main' && 'env' '-C' '.' 'target/release/gunbc' 'run' '--source-root' 'dag' '--entry' 'dag/tools/merge_admission_gate.dag' '--function' 'main'
+          'git' 'fetch' '--no-tags' 'origin' 'main' && 'env' '-C' '.' 'target/release/gunbc' 'run' '--source-root' 'dag' '--source-root' 'src/v2' '--entry' 'dag/tools/merge_admission_gate.dag' '--function' 'main'
         timeout-minutes: 5
   deploy_dashboard_srv1:
     runs-on: [self-hosted, linux, arm64, srv1]

dag/extdeps/git/object_store.dag

@@ -1,7 +1,8 @@
 module extdeps.git.object_store
 
 import std.types { ContentHash, NonEmptyStr, Bytes, Map }
-import std.integer { UInt8, NonNegativeInt }
+import std.integer { UInt8, NonNegativeInt, PositiveInt }
+import std.render_repeat_string_bootstrap { repeat_string }
 import std.measure { ByteSize, byte_size, byte_size_count }
 import std.bytes { bytes_octets, octets_bytes, utf8_encode_bytes }
 import std.cache_interface { ContentAddressedByValue, WriteOnce }
@@ -38,6 +39,13 @@ data git_ls_files_authority: ExternalAuthority = ExternalAuthority {
   }
 }
 
+data git_gitattributes_authority: ExternalAuthority = ExternalAuthority {
+  uri: Uri {
+    scheme: Https
+    locator: "git-scm.com/docs/gitattributes#_conflict_marker_size"
+  }
+}
+
 data git_update_ref_authority: ExternalAuthority = ExternalAuthority {
   uri: Uri {
     scheme: Https
@@ -522,6 +530,24 @@ type GitIndexStage
   | GitIndexStageOurs
   | GitIndexStageTheirs
 
+type GitEffectiveConflictMarkerGrammar {
+  size: PositiveInt
+}
+
+data git_effective_conflict_marker_grammar_note: String = "Per-path effective conflict grammar after Git resolves gitattributes conflict-marker-size. Git defaults each marker to seven characters, but the attribute can choose another positive width for a path; consumers must observe the effective value rather than assume the default. The upstream fact is stored once as std.integer.PositiveInt and all three tokens derive from it, so empty, mismatched, and non-marker grammars are unwritable."
+
+fn git_conflict_marker_begin(grammar: GitEffectiveConflictMarkerGrammar) -> String {
+  repeat_string(s: "<", n: grammar.size)
+}
+
+fn git_conflict_marker_separator(grammar: GitEffectiveConflictMarkerGrammar) -> String {
+  repeat_string(s: "=", n: grammar.size)
+}
+
+fn git_conflict_marker_end(grammar: GitEffectiveConflictMarkerGrammar) -> String {
+  repeat_string(s: ">", n: grammar.size)
+}
+
 type GitIndexEntry {
   path: GitPath
   mode: GitTreeMode