D3024: scmutil: add method for looking up a context given a revision symbol

[martinvonz (Martin von Zweigbergk)]

martinvonz created this revision.
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Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  changectx's constructor currently supports a mix if inputs:
  
  - integer revnums
  - binary nodeids
  - '.', 'tip', 'null'
  - stringified revnums
  - namespaced identifiers (e.g. bookmarks and tags)
  - hex nodeids
  - partial hex nodeids
  
  The first two are always internal [1]. The other five can be specified
  by the user. The third type ('.', 'tip', 'null') often comes from
  either the user or internal callers. We probably have some internal
  callers that pass hex nodeids too, perhaps even partial ones
  (histedit?). There are only a few callers that pass user-supplied
  strings: revsets.stringset, peer.lookup, webutil.changeidctx, and
  maybe one or two more.
  
  Supporting this mix of things in the constructor is convenient, but a
  bit strange, IMO. For example, if repo[node] is given a node that's
  not in the repo, it will first check if it's bookmark etc before
  raising an exception. Of course, the risk of it being a bookmark is
  extremely small, but it just feels ugly.
  
  Also, a problem with having this code in the constructor (whether it
  supports a mix of types or not) is that it's harder to override (I'd
  like to override it, and that's how this series started).
  
  This patch starts moving out the handling of user-supplied strings by
  introducing scmutil.revsymbol(). So far, that just checks that the
  input is indeed a string, and then delegates to repo[symbol]. The
  patch also calls it from revsets.stringset to prove that it works.
  
  [1] Well, you probably can enter a 20-byte binary nodeid on the
  
    command line, but I don't think we should care to preserve
    support for that.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3024

AFFECTED FILES
  mercurial/revset.py
  mercurial/scmutil.py

CHANGE DETAILS

diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -433,6 +433,19 @@
         hexfunc = short
     return '%d:%s' % (rev, hexfunc(node))
 
+def revsymbol(repo, symbol):
+    """Returns a context given a single revision symbol (as string).
+
+    This is similar to revsingle(), but accepts only a single revision symbol,
+    i.e. things like ".", "tip", "1234", "deadbeef", "my-bookmark" work, but
+    not "max(public())".
+    """
+    if not isinstance(symbol, bytes):
+        msg = ("symbol (%s of type %s) was not a string, did you mean "
+               "repo[symbol]?" % (symbol, type(symbol)))
+        raise error.ProgrammingError(msg)
+    return repo[symbol]
+
 def revsingle(repo, revspec, default='.', localalias=None):
     if not revspec and revspec != 0:
         return repo[default]
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -118,7 +118,7 @@
 def stringset(repo, subset, x, order):
     if not x:
         raise error.ParseError(_("empty string is not a valid revision"))
-    x = scmutil.intrev(repo[x])
+    x = scmutil.intrev(scmutil.revsymbol(repo, x))
     if (x in subset
         or x == node.nullrev and isinstance(subset, fullreposet)):
         return baseset([x])



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Cc: mercurial-devel