logtoprocess: sends the canonical command name to the subprocess

logtoprocess: sends the canonical command name to the subprocess

One of the use-case of logtoprocess is to monitor command duration. With the
current code, we only get whatever command name the user typed (either
abbreviated or aliased).

This makes analytics on the collected data more difficult. Stores the
canonical command name in the request object. Pass the stored canonical name
in the `req.ui.log("commandfinish", ...)` call as keyword argument to not
break potential string formatting.

Pass the value as the environment variable named `LTP_COMMAND` to the called
script.

Differential Revision: https://phab.mercurial-scm.org/D4820

--- a/mercurial/dispatch.py	Mon Oct 22 15:47:30 2018 +0200
+++ b/mercurial/dispatch.py	Mon Oct 22 15:51:01 2018 +0200
@@ -66,6 +66,9 @@
         # low-level repo state (for example, changelog) before extensions.
         self.prereposetups = prereposetups or []
 
+        # store the parsed and canonical command
+        self.canonical_command = None
+
     def _runexithandlers(self):
         exc = None
         handlers = self.ui._exithandlers
@@ -243,7 +246,8 @@
                 req.ui.log('uiblocked', 'ui blocked ms',
                            **pycompat.strkwargs(req.ui._blockedtimes))
             req.ui.log("commandfinish", "%s exited %d after %0.2f seconds\n",
-                       msg, ret & 255, duration)
+                       msg, ret & 255, duration,
+                       canonical_command=req.canonical_command)
             try:
                 req._runexithandlers()
             except: # exiting, so no re-raises
@@ -853,6 +857,9 @@
         fullargs = args
         cmd, func, args, options, cmdoptions = _parse(lui, args)
 
+        # store the canonical command name in request object for later access
+        req.canonical_command = cmd
+
         if options["config"] != req.earlyoptions["config"]:
             raise error.Abort(_("option --config may not be abbreviated!"))
         if options["cwd"] != req.earlyoptions["cwd"]:

--- a/tests/test-logtoprocess.t	Mon Oct 22 15:47:30 2018 +0200
+++ b/tests/test-logtoprocess.t	Mon Oct 22 15:51:01 2018 +0200
@@ -17,7 +17,7 @@
   > configitem('logtoprocess', 'foo',
   >     default=None,
   > )
-  > @command(b'foo', [])
+  > @command(b'foobar', [])
   > def foo(ui, repo):
   >     ui.log('foo', 'a message: %s\n', 'spam')
   > EOF
@@ -35,7 +35,8 @@
   >     echo "\$EVENT";
   >     echo "\$MSG1";
   >     echo "\$MSG2";
-  >     echo "\$MSG3") > $TESTTMP/commandfinish.log
+  >     echo "\$MSG3";
+  >     echo "canonical: \$OPT_CANONICAL_COMMAND") > $TESTTMP/commandfinish.log
   > foo=(echo 'logtoprocess foo output:';
   >     echo "\$EVENT";
   >     echo "\$MSG1";
@@ -46,22 +47,23 @@
 ui.log('commandfinish') call. The foo command also uses ui.log.
 
 Use sort to avoid ordering issues between the various processes we spawn:
-  $ hg foo
+  $ hg fooba
   $ sleep 1
   $ cat $TESTTMP/command.log | sort
   
   command
-  foo
-  foo
+  fooba
+  fooba
   logtoprocess command output:
 
 #if no-chg
   $ cat $TESTTMP/commandfinish.log | sort
   
   0
+  canonical: foobar
   commandfinish
-  foo
-  foo exited 0 after * seconds (glob)
+  fooba
+  fooba exited 0 after * seconds (glob)
   logtoprocess commandfinish output:
   $ cat $TESTTMP/foo.log | sort