upgrade: explicitly warn when a `--no-xxx` flag is overwritten

upgrade: explicitly warn when a `--no-xxx` flag is overwritten

Some format upgrade/downgrades -needs- revlog to be recomputed. So we now
detect that individually and warn when it contradict explicitly passed flag.

This is part of a larger series to make `debugupgraderepo` smarter about which
revlog it picks by default.

Differential Revision: https://phab.mercurial-scm.org/D11869

--- a/mercurial/upgrade.py	Mon Dec 06 14:40:13 2021 +0100
+++ b/mercurial/upgrade.py	Mon Dec 06 17:12:21 2021 +0100
@@ -90,6 +90,43 @@
 
     # check if we need to touch revlog and if so, which ones
 
+    touched_revlogs = set()
+    overwrite_msg = _(b'warning: ignoring %14s, as upgrade is changing: %s\n')
+    msg_issued = False
+
+    FL = upgrade_engine.UPGRADE_FILELOGS
+    MN = upgrade_engine.UPGRADE_MANIFEST
+    CL = upgrade_engine.UPGRADE_CHANGELOG
+
+    for action in sorted(up_actions + removed_actions, key=lambda a: a.name):
+        # optimisation does not "requires anything, they just needs it.
+        if action.type != upgrade_actions.FORMAT_VARIANT:
+            continue
+
+        if action.touches_filelogs and FL not in touched_revlogs:
+            if FL in specified_revlogs:
+                if not specified_revlogs[FL]:
+                    msg = overwrite_msg % (b'--no-filelogs', action.name)
+                    ui.warn(msg)
+                    msg_issued = True
+            touched_revlogs.add(FL)
+        if action.touches_manifests and MN not in touched_revlogs:
+            if MN in specified_revlogs:
+                if not specified_revlogs[MN]:
+                    msg = overwrite_msg % (b'--no-manifest', action.name)
+                    ui.warn(msg)
+                    msg_issued = True
+            touched_revlogs.add(MN)
+        if action.touches_changelog and CL not in touched_revlogs:
+            if CL in specified_revlogs:
+                if not specified_revlogs[CL]:
+                    msg = overwrite_msg % (b'--no-changelog', action.name)
+                    ui.warn(msg)
+                    msg_issued = True
+            touched_revlogs.add(CL)
+    if msg_issued:
+        ui.warn((b"\n"))
+
     revlogs = set(upgrade_engine.UPGRADE_ALL_REVLOGS)
     if specified_revlogs:
         # we have some limitation on revlogs to be recloned

--- a/tests/test-upgrade-repo.t	Mon Dec 06 14:40:13 2021 +0100
+++ b/tests/test-upgrade-repo.t	Mon Dec 06 17:12:21 2021 +0100
@@ -944,6 +944,22 @@
 
   $ echo "[format]" > .hg/hgrc
   $ echo "sparse-revlog=no" >> .hg/hgrc
+  $ hg debugupgrade --optimize re-delta-parent --no-manifest --no-backup --quiet
+  warning: ignoring  --no-manifest, as upgrade is changing: sparserevlog
+  
+  ignoring revlogs selection flags, format requirements change: sparserevlog
+  requirements
+     preserved: dotencode, fncache, generaldelta, revlogv1, store (no-rust !)
+     preserved: dotencode, fncache, generaldelta, persistent-nodemap, revlogv1, store (rust !)
+     removed: sparserevlog
+  
+  optimisations: re-delta-parent
+  
+  processed revlogs:
+    - all-filelogs
+    - changelog
+    - manifest
+  
   $ hg debugupgrade --optimize re-delta-parent --run --manifest --no-backup --debug --traceback
   ignoring revlogs selection flags, format requirements change: sparserevlog
   upgrade will perform the following actions: