push: add option to block hg push if no reason is provided

Summary:
We want to start tracking down why people use hg push instead of arc
land. To begin with, let's add an option that will require they provide a reason
to run hg push directly. Later we may block pushes or limit it to a whitelist in
some way.

Reviewed By: quark-zju

Differential Revision: D16156871

fbshipit-source-id: f46c039a91073fa3380d3b4b7f35722829eeb72a

edenscm/mercurial/commands/__init__.py

@@ -4868,6 +4868,13 @@ def push(ui, repo, dest=None, **opts):
             [push]
             pushvars.server = true
 
+        If ``push.requirereason`` is set to true, users will need to pass
+        ``--pushvars PUSH_REASON="..."`` in order to push, and their reason will
+        be logged via ``ui.log(...)``.
+
+        ``push.requirereasonmsg`` can be used to set the message shown to users
+        when they don't provide a reason.
+
     Returns 0 if push was successful, 1 if nothing to push.
     """
 
@@ -4914,6 +4921,16 @@ def push(ui, repo, dest=None, **opts):
                 _("default push revset for path evaluates to an " "empty set")
             )
 
+    if ui.configbool("push", "requirereason"):
+        pushvar = "PUSH_REASON="
+        reasons = list(v for v in opts.get("pushvars", []) if v.startswith(pushvar))
+        if reasons:
+            reason = reasons[-1][len(pushvar):]
+            ui.log("pushreason", "bypassing push block with reason: %s", reason, pushreason=reason)
+        else:
+            msg = ui.config("push", "requirereasonmsg")
+            raise error.Abort(msg, hint="use `--pushvars PUSH_REASON='because ...'`")
+
     opargs = dict(opts.get("opargs", {}))  # copy opargs since we may mutate it
     opargs.setdefault("pushvars", []).extend(opts.get("pushvars", []))
 

edenscm/mercurial/configitems.py

@@ -404,6 +404,8 @@ coreconfigitem("progress", "renderer", default="classic")
 coreconfigitem("progress", "width", default=dynamicdefault)
 coreconfigitem("pull", "automigrate", default=True)
 coreconfigitem("push", "pushvars.server", default=True)
+coreconfigitem("push", "requirereason", default=False)
+coreconfigitem("push", "requirereasonmsg", default="")
 coreconfigitem("sendunbundlereplay", "respondlightly", default=True)
 coreconfigitem("server", "bookmarks-pushkey-compat", default=True)
 coreconfigitem("server", "bundle1", default=True)

tests/test-pushvars.t

@@ -80,6 +80,7 @@ Test Python hooks
   >             ui.write("Got pushvar: %s=%s\n" % (k, v))
   > EOF
 
+  $ cp $HGRCPATH $TESTTMP/hgrc.bak
   $ cat >> $HGRCPATH << EOF
   > [hooks]
   > pretxnchangegroup.pyhook = python:$TESTTMP/pyhook.py:hook
@@ -94,3 +95,28 @@ Test Python hooks
   added 1 changesets with 1 changes to 1 files
   Got pushvar: USERVAR_A=1
   Got pushvar: USERVAR_B=2
+  $ cp $TESTTMP/hgrc.bak $HGRCPATH
+
+Test pushvars for enforcing push reasons
+  $ cat >> .hg/hgrc <<EOF
+  > [push]
+  > requirereason=True
+  > requirereasonmsg="Because I said so"
+  > EOF
+  $ echo c >> a
+  $ hg commit -Aqm c
+  $ hg push
+  pushing to $TESTTMP/repo
+  abort: "Because I said so"
+  (use `--pushvars PUSH_REASON='because ...'`)
+  [255]
+  $ hg push --pushvars PUSH_REASON="I want to"
+  pushing to $TESTTMP/repo
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  $ hg blackbox --pattern '{"legacy_log": {"service": "pushreason"}}'
+  * [legacy][pushreason] bypassing push block with reason: I want to (glob)
+  $ cp $TESTTMP/hgrc.bak $HGRCPATH