verify: this spine still produces this abstraction?

does this spine still produce this abstraction?

A database states an abstraction and carries the markup it was built
from, so re-parsing the one and comparing against the other says whether
the two still agree. Checked as follows:
- automatically and unskippably when a document is built from a
  database, at the moment it is parsed and before anything has been
  written from it.
- on --ocda-verify=<file>, an action of its own that materialises,
  parses every language, compares, reports and writes nothing, the exit
  status being the answer.
- on --no-verify as the escape, warning per document, for a newer spine
  reading an older artefact where the abstraction is expected to differ
  and the output is wanted anyway.

A build ends at the first failure rather than skipping the language.

A document rebuilt from a database now has its whole abstraction built.

(assisted by Claude-Code)

1 files changed, 28 insertions, 0 deletions

diff --git a/src/sisudoc/ocda/abstraction/db_in.d b/src/sisudoc/ocda/abstraction/db_in.d
index 0a01364..986a09d 100644
--- a/src/sisudoc/ocda/abstraction/db_in.d
+++ b/src/sisudoc/ocda/abstraction/db_in.d
@@ -90,6 +90,34 @@ template spineDbLanguages() {
     return _out;
   }
 }
+/+ ↓ the .ssp digest a database recorded for each of its languages.
+     .
+     What verify holds its answer against: the database says which .ssp it was
+     built from, so re-parsing the markup it carries and emitting the .ssp again
+     either reproduces that digest or does not.
+     .
+     Its own template, for the reason spineDbLanguages is: asking a file what it
+     recorded should not instantiate the reader.
++/
+template spineDbSspDigests() {
+  @trusted string[string] spineDbSspDigests(string db_file) {
+    import std.file : exists;
+    import d2sqlite3;
+    string[string] _out;
+    if (!db_file.exists) { return _out; }
+    try {
+      auto db = Database(db_file, SQLITE_OPEN_READONLY);
+      foreach (row; db.execute(
+        "SELECT lang, ssp_digest FROM documents ORDER BY id")
+      ) {
+        _out[row["lang"].as!string] = row["ssp_digest"].as!string;
+      }
+    } catch (Exception ex) {
+      return string[string].init;
+    }
+    return _out;
+  }
+}
 template spineAbstractionDbRead() {
   import std.conv : to;
   import std.file;