compression: display compression level in debugformat

Now that we have options to control the compression level, we teach `hg
debugformat` about them. This is a useful information when comparing
repositories.

Note that we have no trace of the compression level used to store existing
deltas. Actually, it would even varies from one delta to another. So we display
the currently set value.

mercurial/upgrade.py

@@ -334,6 +334,39 b' class compressionengine(formatvariant):'
     def fromconfig(cls, repo):
         return repo.ui.config('experimental', 'format.compression')
 
+@registerformatvariant
+class compressionlevel(formatvariant):
+    name = 'compression-level'
+    default = 'default'
+
+    description = _('compression level')
+
+    upgrademessage = _('revlog content will be recompressed')
+
+    @classmethod
+    def fromrepo(cls, repo):
+        comp = compressionengine.fromrepo(repo)
+        level = None
+        if comp == 'zlib':
+            level = repo.ui.configint('storage', 'revlog.zlib.level')
+        elif comp == 'zstd':
+            level = repo.ui.configint('storage', 'revlog.zstd.level')
+        if level is None:
+            return 'default'
+        return bytes(level)
+
+    @classmethod
+    def fromconfig(cls, repo):
+        comp = compressionengine.fromconfig(repo)
+        level = None
+        if comp == 'zlib':
+            level = repo.ui.configint('storage', 'revlog.zlib.level')
+        elif comp == 'zstd':
+            level = repo.ui.configint('storage', 'revlog.zstd.level')
+        if level is None:
+            return 'default'
+        return bytes(level)
+
 def finddeficiencies(repo):
     """returns a list of deficiencies that the repo suffer from"""
     deficiencies = []

tests/test-upgrade-repo.t

@@ -59,6 +59,7 b' An upgrade of a repository created with '
   sparserevlog:   yes
   plain-cl-delta: yes
   compression:    zlib
+  compression-level: default
   $ hg debugformat --verbose
   format-variant repo config default
   fncache:        yes    yes     yes
@@ -67,6 +68,7 b' An upgrade of a repository created with '
   sparserevlog:   yes    yes     yes
   plain-cl-delta: yes    yes     yes
   compression:    zlib   zlib    zlib
+  compression-level: default default default
   $ hg debugformat --verbose --config format.usefncache=no
   format-variant repo config default
   fncache:        yes     no     yes
@@ -75,6 +77,7 b' An upgrade of a repository created with '
   sparserevlog:   yes    yes     yes
   plain-cl-delta: yes    yes     yes
   compression:    zlib   zlib    zlib
+  compression-level: default default default
   $ hg debugformat --verbose --config format.usefncache=no --color=debug
   format-variant repo config default
   [formatvariant.name.mismatchconfig|fncache:       ][formatvariant.repo.mismatchconfig| yes][formatvariant.config.special|     no][formatvariant.default|     yes]
@@ -83,6 +86,7 b' An upgrade of a repository created with '
   [formatvariant.name.uptodate|sparserevlog:  ][formatvariant.repo.uptodate| yes][formatvariant.config.default|    yes][formatvariant.default|     yes]
   [formatvariant.name.uptodate|plain-cl-delta:][formatvariant.repo.uptodate| yes][formatvariant.config.default|    yes][formatvariant.default|     yes]
   [formatvariant.name.uptodate|compression:   ][formatvariant.repo.uptodate| zlib][formatvariant.config.default|   zlib][formatvariant.default|    zlib]
+  [formatvariant.name.uptodate|compression-level:][formatvariant.repo.uptodate| default][formatvariant.config.default| default][formatvariant.default| default]
   $ hg debugformat -Tjson
   [
    {
@@ -120,6 +124,12 b' An upgrade of a repository created with '
     "default": "zlib",
     "name": "compression",
     "repo": "zlib"
+   },
+   {
+    "config": "default",
+    "default": "default",
+    "name": "compression-level",
+    "repo": "default"
    }
   ]
   $ hg debugupgraderepo
@@ -214,6 +224,7 b' Various sub-optimal detections work'
   sparserevlog:    no
   plain-cl-delta: yes
   compression:    zlib
+  compression-level: default
   $ hg debugformat --verbose
   format-variant repo config default
   fncache:         no    yes     yes
@@ -222,6 +233,7 b' Various sub-optimal detections work'
   sparserevlog:    no    yes     yes
   plain-cl-delta: yes    yes     yes
   compression:    zlib   zlib    zlib
+  compression-level: default default default
   $ hg debugformat --verbose --config format.usegeneraldelta=no
   format-variant repo config default
   fncache:         no    yes     yes
@@ -230,6 +242,7 b' Various sub-optimal detections work'
   sparserevlog:    no     no     yes
   plain-cl-delta: yes    yes     yes
   compression:    zlib   zlib    zlib
+  compression-level: default default default
   $ hg debugformat --verbose --config format.usegeneraldelta=no --color=debug
   format-variant repo config default
   [formatvariant.name.mismatchconfig|fncache:       ][formatvariant.repo.mismatchconfig|  no][formatvariant.config.default|    yes][formatvariant.default|     yes]
@@ -238,6 +251,7 b' Various sub-optimal detections work'
   [formatvariant.name.mismatchdefault|sparserevlog:  ][formatvariant.repo.mismatchdefault|  no][formatvariant.config.special|     no][formatvariant.default|     yes]
   [formatvariant.name.uptodate|plain-cl-delta:][formatvariant.repo.uptodate| yes][formatvariant.config.default|    yes][formatvariant.default|     yes]
   [formatvariant.name.uptodate|compression:   ][formatvariant.repo.uptodate| zlib][formatvariant.config.default|   zlib][formatvariant.default|    zlib]
+  [formatvariant.name.uptodate|compression-level:][formatvariant.repo.uptodate| default][formatvariant.config.default| default][formatvariant.default| default]
   $ hg debugupgraderepo
   repository lacks features recommended by current config options: