Beagle SCM

DIFF-004: clickable difflet URIs — diff:<path>?<from>..<to>#L<n>

Clicking a diff hunk's nav link (e.g. diff:ast/BAST.c#L362) gives "be: no results". The hunk's click-target URI is built with an EMPTY query (graf/WEAVE.c ~861/961: HUNKu8sMakeURI(..,name,empty,line) → diff:<path>#L), so clicking runs wt-vs-base (beagle/BE.cli.c:251) — empty for a committed file. diff:'s range form ?from#to spends the fragment on <to>, leaving no room for #L. The weave verb already takes a .. range in the QUERY (graf/GRAF.exe.c:483-493), freeing the fragment. Adopt that for diff:: clickable difflets become diff:<path>?<from>..<to>#L<n>. Method: Issues.

Input

Context

• Nav-URI is the per-hunk U click target bro renders; today it omits the version → wt-vs-base → "no results" on a committed file (pre-existing; DIFF-003 eaa75793 made file diffs worth clicking, exposing it).
• diff: range = ?from#to (query=from, fragment=to) — no room for #L. weave file?from..to (GRAF.exe.c:483-493) puts both refs in the query.
• Repro: be diff:graf/WEAVE.c#L100 → empty; be diff:graf/WEAVE.c?<from>..<to> (range in query) leaves the fragment free for #L.

Goals

• diff: accepts ?<from>..<to> (range via .. in the query); the fragment is the line anchor #L<n> (jump), not the range to.
• Diff hunks emit clickable nav URIs diff:<path>?<from>..<to>#L<hunk_line>; clicking opens the file-scoped (whole-file, DIFF-003) diff at that line.
• wt-vs-base hunks keep diff:<path>#L<n> (no query — correct, file is dirty).
• Commit-show (diff:?<sha> → GRAFDiffTreeRefs(parent,sha)) per-file nav = diff:<path>?<parent>..<sha>#L<n>.

Constraints

• Reuse the weave verb's .. split (GRAF.exe.c:483-493) — do NOT reinvent.
• Guard the bare ?.. parent-branch relative form (URI.mkd:42): the split must not fire on a relative ../?./x ref.
• Producer/renderer split: graf emits the URI (data); bro owns the click + #L jump (existing fragment handling). abc/ untouched.

WIP

Design decisions (settled with user 2026-06-15)

• URI form diff:<path>?<from>..<to>#L<n> chosen over ?from#to:L<n> (the #sym:L overload) — it matches the live weave form and keeps the fragment purely a line anchor. Legacy ?from#to may stay as a fallback when the query has no .. (back-compat), but .. is the canonical range.

TODOs

• Repro-first: test/diff/12-difflet-click — assert (a) diff:<path>?<from>..<to>#L<n> resolves to the file's range diff (whole file, far unchanged line + change present) and (b) a tree/commit diff's per-file hunk URI is the ?from..to#L form, NOT the empty-query form, in Plain/TLV. Confirm red first.
• Parse: diff: query with .. → split from/to (reuse GRAF.exe.c 483-493), route to the range diff; fragment = line anchor. Guard ?...
• Nav-URI: thread a u8cs navver (<from>..<to>) GRAFDiffTreeRefs / GRAFWeaveDiff → GRAFDiff2Layer → WEAVEEmitDiff/WEAVEEmitFull; the FLUSH macros build scheme + name + "?" + navver then HUNKu8sMakeURI(empty path, sym, line) for #L. wt-vs-base callers pass empty navver.
• Spec/usage: update URI.mkd (diff:?a..b + #L) and the GRAF diff usage string. Keep weave behaviour unchanged.

Blockers and bummers

• Signatures to extend: GRAFDiff2Layer (DIFFREF.c:136 / GRAF.h:335), GRAFDiffTreeRefs (GRAF.h:326), GRAFWeaveDiff (BLAME.c / GRAF.h:301), GRAFDiffWtFile/WtTree (GRAF.h:324-325), WEAVEEmitDiff/Full (WEAVE.h:180/190) — wide but mechanical.

Outcome

• Landed 7317bb48: shared graf_query_range() factors the weave .. split (guards relative ?../?./x); diff: takes ?<from>..<to> as the canonical range, fragment kept free for #L<n> (legacy ?from#to = no-.. fallback). navver (from..to) threaded GRAFDiffTreeRefs/GRAFWeaveDiff → GRAFDiff2Layer → WEAVEEmitDiff/Full so hunks emit diff:<path>?<from>..<to>#L; wt-vs-base + cat: pass empty → bare #L. Test 12-difflet-click; 374/374.