refactor(bootstrap): encapsulate max_release_age and improve filter logging

Encapsulate max_release_age behind set_max_release_age(days) method on
WorkContext to prevent callers from setting it to arbitrary types.
Restructure filtering logs to show the pipeline: total candidates found,
then candidates remaining after each filter step.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Rohan Devasthale <rdevasth@redhat.com>

Author: rd4398

e2e/test_bootstrap_max_release_age.sh

@@ -76,7 +76,7 @@ fi
 # Verify that max-release-age filtering was applied (check log)
 echo ""
 echo "Checking log for max-release-age filtering..."
-if grep -q "filtered.*versions by max release age" "$OUTDIR/bootstrap.log"; then
+if grep -q "published within.*days" "$OUTDIR/bootstrap.log"; then
   echo "✓ Log confirms max-release-age filtering was applied"
 else
   echo "✗ No max-release-age filtering found in log"

src/fromager/commands/bootstrap.py

@@ -181,7 +181,7 @@ def bootstrap(
             skip_constraints = True
 
     if max_release_age > 0:
-        wkctx.max_release_age = timedelta(days=max_release_age)
+        wkctx.set_max_release_age(max_release_age)
         logger.info(
             "max release age: rejecting versions older than %d days",
             max_release_age,

src/fromager/context.py

@@ -114,7 +114,15 @@ def __init__(
         self._parallel_builds = False
 
         self.cooldown: Cooldown | None = cooldown
-        self.max_release_age: datetime.timedelta | None = max_release_age
+        self._max_release_age: datetime.timedelta | None = max_release_age
+
+    @property
+    def max_release_age(self) -> datetime.timedelta | None:
+        return self._max_release_age
+
+    def set_max_release_age(self, days: int) -> None:
+        """Set the maximum release age in days."""
+        self._max_release_age = datetime.timedelta(days=days)
 
     def enable_parallel_builds(self) -> None:
         self._parallel_builds = True

src/fromager/resolver.py

@@ -272,29 +272,39 @@ def find_all_matching_from_provider(
 
     # Materialize candidates so we can iterate more than once if filtering
     candidates_list = list(candidates)
+    logger.info(
+        "%s: found %d candidate(s) matching %s",
+        req.name,
+        len(candidates_list),
+        req,
+    )
 
     if max_age_cutoff is not None:
+        max_age_days = (
+            datetime.datetime.now(datetime.UTC) - max_age_cutoff
+        ).days
         filtered = [
             c
             for c in candidates_list
             if c.upload_time is None or c.upload_time >= max_age_cutoff
         ]
         if filtered:
-            dropped = len(candidates_list) - len(filtered)
-            if dropped > 0:
-                logger.info(
-                    "%s: filtered %d/%d versions by max release age",
-                    req.name,
-                    dropped,
-                    len(candidates_list),
-                )
+            logger.info(
+                "%s: have %d candidate(s) of %s published within %d days",
+                req.name,
+                len(filtered),
+                req,
+                max_age_days,
+            )
             candidates_list = filtered
         else:
             logger.warning(
-                "%s: all %d versions are older than max release age cutoff, "
-                "keeping all versions to avoid empty resolution",
+                "%s: all %d candidate(s) of %s are older than %d days, "
+                "keeping all to avoid empty resolution",
                 req.name,
                 len(candidates_list),
+                req,
+                max_age_days,
             )
 
     # Convert candidates to list of (url, version) tuples

tests/test_cooldown.py

@@ -711,7 +711,9 @@ def test_max_release_age_filters_old_versions(
     assert "2.0.0" in versions
     assert "1.3.2" in versions
     assert "1.2.2" not in versions
-    assert "filtered 1/3 versions by max release age" in caplog.text
+    assert "found 3 candidate(s)" in caplog.text
+    assert "have 2 candidate(s)" in caplog.text
+    assert "published within" in caplog.text
 
 
 def test_max_release_age_keeps_only_recent(
@@ -733,7 +735,9 @@ def test_max_release_age_keeps_only_recent(
 
     versions = [str(v) for _, v in results]
     assert versions == ["2.0.0"]
-    assert "filtered 2/3 versions by max release age" in caplog.text
+    assert "found 3 candidate(s)" in caplog.text
+    assert "have 1 candidate(s)" in caplog.text
+    assert "published within" in caplog.text
 
 
 def test_max_release_age_disabled_returns_all() -> None:
@@ -774,7 +778,7 @@ def test_max_release_age_all_too_old_keeps_all(
 
     versions = [str(v) for _, v in results]
     assert len(versions) == 3
-    assert "keeping all versions to avoid empty resolution" in caplog.text
+    assert "keeping all to avoid empty resolution" in caplog.text
 
 
 def test_max_release_age_candidates_without_upload_time_pass_through() -> None:
@@ -833,7 +837,7 @@ def test_compute_max_age_cutoff_with_cooldown(
         min_age=datetime.timedelta(days=7),
         bootstrap_time=_BOOTSTRAP_TIME,
     )
-    tmp_context.max_release_age = datetime.timedelta(days=30)
+    tmp_context.set_max_release_age(30)
     cutoff = resolver._compute_max_age_cutoff(tmp_context)
     assert cutoff == _BOOTSTRAP_TIME - datetime.timedelta(days=30)
 
@@ -843,7 +847,7 @@ def test_compute_max_age_cutoff_without_cooldown(
 ) -> None:
     """_compute_max_age_cutoff uses current time when no cooldown is set."""
     tmp_context.cooldown = None
-    tmp_context.max_release_age = datetime.timedelta(days=30)
+    tmp_context.set_max_release_age(30)
     cutoff = resolver._compute_max_age_cutoff(tmp_context)
     assert cutoff is not None
     expected = datetime.datetime.now(datetime.UTC) - datetime.timedelta(days=30)
@@ -854,6 +858,5 @@ def test_compute_max_age_cutoff_disabled(
     tmp_context: context.WorkContext,
 ) -> None:
     """_compute_max_age_cutoff returns None when max_release_age is not set."""
-    tmp_context.max_release_age = None
     cutoff = resolver._compute_max_age_cutoff(tmp_context)
     assert cutoff is None