tags: write a separate tags cache file for unfiltered repos

Since we changed the format of the tags cache, we should bump the
filename. Before this patch, "tags" was being used for unfiltered
repositories. Change the naming scheme to be consistent and ensure
that a new cache file is used.

While I was here, I updated the docs to describe the existence of
multiple caches. I also added explicit test coverage for the creation of
the unfiltered tags cache.

mercurial/tags.py

@@ -36,10 +36,11 import time
 # repositories with very large manifests. Multiplied by dozens or even
 # hundreds of heads and there is a significant performance concern.
 #
-# The "tags" cache stores information about the history of tags.
+# There also exist a separate cache file for each repository filter.
+# These "tags-*" files store information about the history of tags.
 #
-# The cache file consists of a cache validation line followed by a history
-# of tags.
+# The tags cache files consists of a cache validation line followed by
+# a history of tags.
 #
 # The cache validation line has the format:
 #
@@ -239,7 +240,7 def _updatetags(filetags, tagtype, allta
 
 def _filename(repo):
     """name of a tagcache file for a given repo or repoview"""
-    filename = 'cache/tags'
+    filename = 'cache/tags2'
     if repo.filtername:
         filename = '%s-%s' % (filename, repo.filtername)
     return filename

tests/test-obsolete-tag-cache.t

@@ -47,7 +47,7 Trigger tags cache population by doing s
   test2                              2:d75775ffbc6b
   test1                              0:55482a6fb4b1
 
-  $ cat .hg/cache/tags-visible
+  $ cat .hg/cache/tags2-visible
   5 2942a772f72a444bef4bef13874d515f50fa27b6
   042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
   55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
@@ -62,7 +62,7 Hiding a non-tip changeset should change
   head2                              4:042eb6bfcc49
   test1                              0:55482a6fb4b1
 
-  $ cat .hg/cache/tags-visible
+  $ cat .hg/cache/tags2-visible
   5 2942a772f72a444bef4bef13874d515f50fa27b6 f34fbc9a9769ba9eff5aff3d008a6b49f85c08b1
   042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
   55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
@@ -82,7 +82,7 Hiding another changeset should cause th
   tip                                5:2942a772f72a
   head2                              4:042eb6bfcc49
 
-  $ cat .hg/cache/tags-visible
+  $ cat .hg/cache/tags2-visible
   5 2942a772f72a444bef4bef13874d515f50fa27b6 2fce1eec33263d08a4d04293960fc73a555230e4
   042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
 
@@ -91,3 +91,23 Hiding another changeset should cause th
   1970/01/01 00:00:00 bob> 1/1 cache hits/lookups in * seconds (glob)
   1970/01/01 00:00:00 bob> writing tags cache file with 1 tags
   1970/01/01 00:00:00 bob> tags exited 0 after * seconds (glob)
+
+Resolving tags on an unfiltered repo writes a separate tags cache
+
+  $ hg --hidden tags
+  tip                                5:2942a772f72a
+  head2                              4:042eb6bfcc49
+  test2                              2:d75775ffbc6b
+  test1                              0:55482a6fb4b1
+
+  $ cat .hg/cache/tags2
+  5 2942a772f72a444bef4bef13874d515f50fa27b6
+  042eb6bfcc4909bad84a1cbf6eb1ddf0ab587d41 head2
+  55482a6fb4b1881fa8f746fd52cf6f096bb21c89 test1
+  d75775ffbc6bca1794d300f5571272879bd280da test2
+
+  $ hg blackbox -l 4
+  1970/01/01 00:00:00 bob> --hidden tags
+  1970/01/01 00:00:00 bob> 2/2 cache hits/lookups in * seconds (glob)
+  1970/01/01 00:00:00 bob> writing tags cache file with 3 tags
+  1970/01/01 00:00:00 bob> --hidden tags exited 0 after * seconds (glob)

tests/test-tags.t

@@ -9,7 +9,7 setup
 Helper functions:
 
   $ cacheexists() {
-  >   [ -f .hg/cache/tags-visible ] && echo "tag cache exists" || echo "no tag cache"
+  >   [ -f .hg/cache/tags2-visible ] && echo "tag cache exists" || echo "no tag cache"
   > }
 
   $ fnodescacheexists() {
@@ -56,7 +56,7 No fnodes cache because .hgtags file doe
 
 Try corrupting the cache
 
-  $ printf 'a b' > .hg/cache/tags-visible
+  $ printf 'a b' > .hg/cache/tags2-visible
   $ hg identify
   acb14030fe0a tip
   $ cacheexists
@@ -102,7 +102,7 The cache should have an empty entry for
 
 Repeat with cold tag cache:
 
-  $ rm -f .hg/cache/tags-visible .hg/cache/hgtagsfnodes1
+  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
 
@@ -117,7 +117,7 Repeat with cold tag cache:
 And again, but now unable to write tag cache:
 
 #if unix-permissions
-  $ rm -f .hg/cache/tags-visible .hg/cache/hgtagsfnodes1
+  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ chmod 555 .hg/cache
   $ hg identify
   b9154636be93 tip
@@ -126,7 +126,7 And again, but now unable to write tag c
 
 Tag cache debug info written to blackbox log
 
-  $ rm -f .hg/cache/tags-visible .hg/cache/hgtagsfnodes1
+  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
   $ hg blackbox -l 5
@@ -138,7 +138,7 Tag cache debug info written to blackbox
 
 Failure to acquire lock results in no write
 
-  $ rm -f .hg/cache/tags-visible .hg/cache/hgtagsfnodes1
+  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ echo 'foo:1' > .hg/wlock
   $ hg identify
   b9154636be93 tip
@@ -154,7 +154,7 Failure to acquire lock results in no wr
 
   $ rm .hg/wlock
 
-  $ rm -f .hg/cache/tags-visible .hg/cache/hgtagsfnodes1
+  $ rm -f .hg/cache/tags2-visible .hg/cache/hgtagsfnodes1
   $ hg identify
   b9154636be93 tip
 
@@ -311,7 +311,7 Detailed dump of tag info:
 
 Dump cache:
 
-  $ cat .hg/cache/tags-visible
+  $ cat .hg/cache/tags2-visible
   4 0c192d7d5e6b78a714de54a2e9627952a877e25a
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
   bbd179dfa0a71671c253b3ae0aa1513b60d199fa bar
@@ -353,7 +353,7 Errors writing to .hgtags fnodes cache a
   $ hg commit -m throwaway2
 
   $ chmod a-w .hg/cache/hgtagsfnodes1
-  $ rm -f .hg/cache/tags-visible
+  $ rm -f .hg/cache/tags2-visible
 
   $ hg tags
   tip                                6:b968051b5cf3
@@ -369,7 +369,7 Errors writing to .hgtags fnodes cache a
   $ chmod a+w .hg/cache/hgtagsfnodes1
 #endif
 
-  $ rm -f .hg/cache/tags-visible
+  $ rm -f .hg/cache/tags2-visible
   $ hg tags
   tip                                6:b968051b5cf3
   bar                                1:78391a272241
@@ -521,7 +521,7 Strip 2: destroy whole branch, no old he
   $ hg tags                  # partly stale
   tip                                4:735c3ca72986
   bar                                0:bbd179dfa0a7
-  $ rm -f .hg/cache/tags-visible
+  $ rm -f .hg/cache/tags2-visible
   $ hg tags                  # cold cache
   tip                                4:735c3ca72986
   bar                                0:bbd179dfa0a7