tags-cache: directly perform a monimal walk for hgtagsfnodescache warming
We do something narrower than the path retrieving data. So lets use dedicated
code instead.
This provides further useful speedup:
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# benchmark.name = hg.debug.debug-update-cache
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.pre-state = warm
before-this-series: 19.947581
skip-fnode-filter: 18.916804 (-5.17%, -1.03)
use-rev-num: 17.493725 (-12.30%, -2.45)
this-changesets: 15.919466 (-20.19%, -4.03)
$ hg init
$ touch a
$ hg add a
$ hg ci -m "a"
$ echo 123 > b
$ hg add b
$ hg diff --nodates
diff -r 3903775176ed b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
$ hg diff --nodates -r tip
diff -r 3903775176ed b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
$ echo foo > a
$ hg diff --nodates
diff -r 3903775176ed a
--- a/a
+++ b/a
@@ -0,0 +1,1 @@
+foo
diff -r 3903775176ed b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
$ hg diff -r ""
hg: parse error: empty query
[10]
$ hg diff -r tip -r ""
hg: parse error: empty query
[10]
Remove a file that was added via merge. Since the file is not in parent 1,
it should not be in the diff.
$ hg ci -m 'a=foo' a
$ hg co -Cq null
$ echo 123 > b
$ hg add b
$ hg ci -m "b"
created new head
$ hg merge 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg rm -f a
$ hg diff --nodates
Rename a file that was added via merge. Since the rename source is not in
parent 1, the diff should be relative to /dev/null
$ hg co -Cq 2
$ hg merge 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg mv a a2
$ hg diff --nodates
diff -r cf44b38435e5 a2
--- /dev/null
+++ b/a2
@@ -0,0 +1,1 @@
+foo
$ hg diff --nodates --git
diff --git a/a2 b/a2
new file mode 100644
--- /dev/null
+++ b/a2
@@ -0,0 +1,1 @@
+foo