[PATCH 01 of 11] debuginstall: print compression engine support

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1479581661 28800
#      Sat Nov 19 10:54:21 2016 -0800
# Node ID 55af8a76a48c276924a0ff9fbf4d2db1c2b31711
# Parent  9375077f1ace71dfa2fc87a1d4eaeae8de267e20
debuginstall: print compression engine support

Since compression engines may be provided by extensions and since
not all registered compression engines may be available to use,
it seems useful to provide a mechanism to see the state of known
compression engines.

This commit teaches `hg debuginstall` to print info on known and
available compression engines.

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2579,6 +2579,16 @@ def debuginstall(ui, **opts):
         problems += 1
     fm.condwrite(err, 'extensionserror', " %s\n", err)
 
+    compengines = util.compengines._engines.values()
+    fm.write('compengines', _('checking registered compression engines (%s)\n'),
+             fm.formatlist(sorted(e.name() for e in compengines),
+                           name='compengine', fmt='%s', sep=', '))
+    fm.write('compenginesavail', _('checking available compression engines '
+                                   '(%s)\n'),
+             fm.formatlist(sorted(e.name() for e in compengines
+                                  if e.available()),
+                           name='compengine', fmt='%s', sep=', '))
+
     # templates
     p = templater.templatepaths()
     fm.write('templatedirs', 'checking templates (%s)...\n', ' '.join(p))
diff --git a/tests/test-install.t b/tests/test-install.t
--- a/tests/test-install.t
+++ b/tests/test-install.t
@@ -11,6 +11,8 @@ hg debuginstall
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
+  checking registered compression engines (*zlib*) (glob)
+  checking available compression engines (*zlib*) (glob)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (* -c "import sys; sys.exit(0)") (glob)
@@ -21,6 +23,8 @@ hg debuginstall JSON
   $ hg debuginstall -Tjson | sed 's|\\\\|\\|g'
   [
    {
+    "compengines": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
+    "compenginesavail": ["bz2", "bz2truncated", "none", "zlib"*], (glob)
     "defaulttemplate": "*mercurial?templates?map-cmdline.default", (glob)
     "defaulttemplateerror": null,
     "defaulttemplatenotfound": "default",
@@ -58,6 +62,8 @@ hg debuginstall with no username
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
+  checking registered compression engines (*zlib*) (glob)
+  checking available compression engines (*zlib*) (glob)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (* -c "import sys; sys.exit(0)") (glob)
@@ -85,6 +91,8 @@ path variables are expanded (~ is the sa
   checking Mercurial custom build (*) (glob)
   checking module policy (*) (glob)
   checking installed modules (*mercurial)... (glob)
+  checking registered compression engines (*zlib*) (glob)
+  checking available compression engines (*zlib*) (glob)
   checking templates (*mercurial?templates)... (glob)
   checking default template (*mercurial?templates?map-cmdline.default) (glob)
   checking commit editor... (* -c "import sys; sys.exit(0)") (glob)