[PATCH 04 of 12] upgrade: split finding deficiencies from finding optimisations

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at ens-lyon.org>
# Date 1491850852 -7200
#      Mon Apr 10 21:00:52 2017 +0200
# Node ID aeda2237481d03670c215fc0ef215e26f4415bcb
# Parent  0435560ab3d11a894a2be7dfcc0ad4e12d5c4b1b
# EXP-Topic upgraderepo
# Available At https://www.mercurial-scm.org/repo/users/marmoute/mercurial/
#              hg pull https://www.mercurial-scm.org/repo/users/marmoute/mercurial/ -r aeda2237481d
upgrade: split finding deficiencies from finding optimisations

Our ultimate goal is to make it easier to get a diagnostic of the repository
format. A first important and step for that is to separate part related to
repository format from the optimisation. We start by having two different
functions returning the two categories of possible "improvement".

diff --git a/mercurial/upgrade.py b/mercurial/upgrade.py
--- a/mercurial/upgrade.py
+++ b/mercurial/upgrade.py
@@ -138,22 +138,18 @@ class improvement(object):
         for k, v in kwargs.items():
             setattr(self, k, v)
 
-def findimprovements(repo):
-    """Determine improvements that can be made to the repo during upgrade.
-
-    Returns a list of ``upgradeimprovement`` describing repository deficiencies
-    and optimizations.
-    """
+def finddeficiencies(repo):
+    """returns a list of deficiencies that the repo suffer from"""
     newreporeqs = localrepo.newreporequirements(repo)
 
-    improvements = []
+    deficiencies = []
 
     # We could detect lack of revlogv1 and store here, but they were added
     # in 0.9.2 and we don't support upgrading repos without these
     # requirements, so let's not bother.
 
     if 'fncache' not in repo.requirements:
-        improvements.append(improvement(
+        deficiencies.append(improvement(
             name='fncache',
             type=deficiency,
             description=_('long and reserved filenames may not work correctly; '
@@ -165,7 +161,7 @@ def findimprovements(repo):
             fromconfig='fncache' in newreporeqs))
 
     if 'dotencode' not in repo.requirements:
-        improvements.append(improvement(
+        deficiencies.append(improvement(
             name='dotencode',
             type=deficiency,
             description=_('storage of filenames beginning with a period or '
@@ -176,7 +172,7 @@ def findimprovements(repo):
             fromconfig='dotencode' in newreporeqs))
 
     if 'generaldelta' not in repo.requirements:
-        improvements.append(improvement(
+        deficiencies.append(improvement(
             name='generaldelta',
             type=deficiency,
             description=_('deltas within internal storage are unable to '
@@ -200,7 +196,7 @@ def findimprovements(repo):
     for rev in cl:
         chainbase = cl.chainbase(rev)
         if chainbase != rev:
-            improvements.append(improvement(
+            deficiencies.append(improvement(
                 name='removecldeltachain',
                 type=deficiency,
                 description=_('changelog storage is using deltas instead of '
@@ -214,12 +210,15 @@ def findimprovements(repo):
                 fromconfig=True))
             break
 
-    # Now for the optimizations.
+    return deficiencies
 
+def findoptimizations(repo):
+    """Determine optimisation that could be used during upgrade"""
     # These are unconditionally added. There is logic later that figures out
     # which ones to apply.
+    optimizations = []
 
-    improvements.append(improvement(
+    optimizations.append(improvement(
         name='redeltaparent',
         type=optimisation,
         description=_('deltas within internal storage will be recalculated to '
@@ -232,7 +231,7 @@ def findimprovements(repo):
         upgrademessage=_('deltas within internal storage will choose a new '
                          'base revision if needed')))
 
-    improvements.append(improvement(
+    optimizations.append(improvement(
         name='redeltamultibase',
         type=optimisation,
         description=_('deltas within internal storage will be recalculated '
@@ -249,7 +248,7 @@ def findimprovements(repo):
                          'parents; may slow down execution time '
                          'significantly')))
 
-    improvements.append(improvement(
+    optimizations.append(improvement(
         name='redeltaall',
         type=optimisation,
         description=_('deltas within internal storage will always be '
@@ -260,14 +259,15 @@ def findimprovements(repo):
                          'recomputed; this will likely drastically slow down '
                          'execution time')))
 
-    return improvements
+    return optimizations
 
 def determineactions(repo, improvements, sourcereqs, destreqs,
                             optimize):
     """Determine upgrade actions that will be performed.
 
-    Given a list of improvements as returned by ``upgradefindimprovements``,
-    determine the list of upgrade actions that will be performed.
+    Given a list of improvements as returned by ``finddeficiencies`` and
+    ``findoptimizations``, determine the list of upgrade actions that
+    will be performed.
 
     The role of this function is to filter improvements if needed, apply
     recommended optimizations from the improvements list that make sense,
@@ -621,7 +621,7 @@ def upgraderepo(ui, repo, run=False, opt
                           _(', ').join(sorted(unsupportedreqs)))
 
     # Find and validate all improvements that can be made.
-    improvements = findimprovements(repo)
+    improvements = finddeficiencies(repo) + findoptimizations(repo)
     for i in improvements:
         if i.type not in (deficiency, optimisation):
             raise error.Abort(_('unexpected improvement type %s for %s') % (