Restore the +test build marker and drop the now-unneeded version-shortcode string guard

PR #14894 rewrote init.lua's version() to always return a pandoc.types.Version,
normalizing the quarto-version filter param to its leading dotted-numeric
component. quarto.version can no longer be a plain string, so the tostring()
fallback added to version.lua for that case guards a condition that cannot
occur, and main's own quarto-version-repr test asserts table.concat succeeds
across plain, four-component, build-metadata, and non-numeric inputs.

The +test.<date> build-metadata marker on built test distributions is kept
deliberately (D2 in llm-docs/built-version-testing-architecture.md): it lets a
built test dist announce itself as a CI trial build in `quarto --version`
while keeping quarto-required range comparisons valid, and #14894 already
makes the marker invisible to Lua filters, which was the only real problem it
used to cause.

Author: cderv

.github/workflows/test-smokes-built.yml

@@ -54,10 +54,11 @@ jobs:
         shell: bash
         run: echo "sha=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
 
-      - name: Compute build version
+      - name: Compute version marker
         id: version
         shell: bash
-        run: echo "version=$(cat version.txt)" >> "$GITHUB_OUTPUT"
+        # Build metadata keeps quarto-required range checks valid.
+        run: echo "version=$(cat version.txt)+test.$(date +%Y%m%d)" >> "$GITHUB_OUTPUT"
 
       - name: Build dist tarball
         uses: ./.github/actions/build-dist-tarball

llm-docs/built-version-testing-architecture.md

@@ -217,17 +217,13 @@ The trigger fires after every completed create-release run, including manual and
 
 **Revisit when:** maintainers want a single nightly build-and-test status and are willing to couple the workflows.
 
-### D2. Version stamp: the plain three-component version (`X.Y.Z`)
+### D2. Version marker: semver *build metadata* (`X.Y.Z+test.YYYYMMDD`)
 
-Built test distributions use `$(cat version.txt)`, a plain `X.Y.Z`. Pandoc's
-`Version` type, used by the `version` shortcode, cannot parse semver build
-metadata such as `+test.YYYYMMDD`; a plain version also matches a release
-artifact more closely. The `99.9.9` sentinel still distinguishes dev mode.
-
-Do not use a prerelease suffix: prerelease versions fail ordinary `>=X.Y`
-`quarto-required` ranges. Do not add a fourth numeric component: it is not
-valid semver. Identify trial builds by workflow, ref, and SHA instead of the
-version string.
+Built test distributions use `$(cat version.txt)+test.$(date +%Y%m%d)`.
+Do not use a prerelease suffix, which fails plain `>=X.Y` `quarto-required` ranges, or a fourth numeric component, which is invalid semver.
+Build metadata preserves range comparisons while distinguishing the build from the `99.9.9` dev version.
+Lua filters see the marker stripped: `init.lua` normalizes the `quarto-version` param to its leading dotted-numeric component, so `quarto.version` is `X.Y.Z` while `quarto --version` reports the full stamp.
+The marker is therefore observable through the CLI, not through `quarto.version`.
 
 ### D3. Dist outside the checkout + `99.9.9` sentinel refusal
 

src/resources/extensions/quarto/version/version.lua

@@ -1,5 +1,5 @@
 return {
   ['version'] = function(args, kwargs, meta)
-    return tostring(quarto.version)
+    return table.concat(quarto.version, '.')
   end
 }

tests/README.md

@@ -490,7 +490,7 @@ To run in binary mode locally:
 ```bash
 # 1. Build a distribution (after ./configure.sh)
 cd package/src
-./quarto-bld prepare-dist --set-version "$(cat ../../version.txt)"
+./quarto-bld prepare-dist --set-version "$(cat ../../version.txt)+test.$(date +%Y%m%d)"
 cd ../..
 
 # 2. Copy the distribution outside the checkout. An in-repo launcher uses