config: load .hg/hgrc.dynamic

Summary:
Adds .hg/hgrc.dynamic to the default load path, before .hg/hgrc though,
so it can be override.

Reviewed By: quark-zju

Differential Revision: D21310921

fbshipit-source-id: 288a2a2ba671943a9f8532489c29e819f9d891e1

eden/scm/edenscm/mercurial/dispatch.py

@@ -46,6 +46,7 @@ from . import (
     registrar,
     scmutil,
     ui as uimod,
+    uiconfig,
     util,
 )
 from .i18n import _
@@ -943,12 +944,15 @@ def _log_exception(lui, e):
         pass
 
 
-def _getlocal(ui, rpath, wd=None):
+def _getlocal(ui, rpath):
     """Return (path, local ui object) for the given target path.
 
     Takes paths in [cwd]/.hg/hgrc into account."
     """
-    if wd is None:
+    if rpath:
+        path = ui.expandpath(rpath)
+        lui = ui.copy()
+    else:
         try:
             wd = pycompat.getcwd()
         except OSError as e:
@@ -964,16 +968,17 @@ def _getlocal(ui, rpath, wd=None):
                 _("error getting current working directory: %s")
                 % encoding.strtolocal(e.strerror)
             )
-    path = cmdutil.findrepo(wd) or ""
-    if not path:
-        lui = ui
-    else:
-        lui = ui.copy()
-        lui.readconfig(os.path.join(path, ".hg", "hgrc"), path)
+        path = cmdutil.findrepo(wd) or ""
 
-    if rpath:
-        path = lui.expandpath(rpath)
-        lui = ui.copy()
+        if not path:
+            lui = ui
+        else:
+            lui = ui.copy()
+
+    if path:
+        uiconfig.loaddynamicconfig(lui, path)
+
+        # Load the primary config after the dynamic one, so it overwrites it
         lui.readconfig(os.path.join(path, ".hg", "hgrc"), path)
 
     return path, lui

eden/scm/edenscm/mercurial/localrepo.py

@@ -66,6 +66,7 @@ from . import (
     transaction,
     treestate,
     txnutil,
+    uiconfig,
     util,
     vfs as vfsmod,
     visibility,
@@ -439,6 +440,8 @@ class localrepository(object):
         # This list it to be filled by extension during repo setup
         self._phasedefaults = []
         try:
+            uiconfig.loaddynamicconfig(self.ui, self.root)
+            # Load the primary config after the dynamic one, so it overwrites it
             self.ui.readconfig(self.localvfs.join("hgrc"), self.root)
             self._loadextensions()
         except IOError:

eden/scm/edenscm/mercurial/uiconfig.py

@@ -12,10 +12,13 @@ from __future__ import absolute_import
 
 import contextlib
 import os
+import subprocess
+import time
 from typing import List, Optional, Tuple
 
 from bindings import configparser
 
+from ..hgext.extutil import runbgcommand
 from . import configitems, error, pycompat, util
 from .encoding import unifromlocal, unitolocal
 from .i18n import _
@@ -544,3 +547,29 @@ def parselist(value):
         return [unitolocal(v) for v in configparser.parselist(unifromlocal(value))]
     else:
         return value
+
+
+def loaddynamicconfig(ui, path):
+    if ui.configbool("configs", "loaddynamicconfig", False):
+        hgrcdyn = os.path.join(path, ".hg", "hgrc.dynamic")
+
+        if ui.configbool("configs", "autogeneratedynamicconfig", False):
+            if not os.path.exists(hgrcdyn):
+                try:
+                    ui.debug("synchronously generating dynamic config\n")
+                    subprocess.check_call(["hg", "debugdynamicconfig"])
+                except Exception as ex:
+                    raise error.Abort(
+                        _("unable to generate dynamic Mercurial config: %s") % ex
+                    )
+
+        ui.readconfig(hgrcdyn, path)
+
+        generationtime = ui.configint("configs", "generationtime", -1)
+        if generationtime != -1:
+            mtimelimit = time.time() - generationtime
+            if not os.path.exists(hgrcdyn) or os.lstat(hgrcdyn).st_mtime < mtimelimit:
+                # TODO: some how prevent kicking off the background process if
+                # the file is read-only or if the previous kick offs failed.
+                ui.debug("background generating dynamic config\n")
+                runbgcommand(["hg", "debugdynamicconfig"], os.environ.copy())

eden/scm/lib/dynamicconfig/Cargo.toml

@@ -8,6 +8,7 @@ anyhow = "1.0.19"
 configparser = { path = "../configparser" }
 hgtime = { path = "../hgtime" }
 hostname = "0.3"
+minibytes = { path = "../minibytes" }
 os_info = "2.0.1"
 
 [dev-dependencies]

eden/scm/lib/dynamicconfig/src/lib.rs

@@ -14,6 +14,7 @@ use std::path::Path;
 
 use anyhow::{anyhow, bail, Result};
 use hostname;
+use minibytes::Text;
 
 use configparser::config::ConfigSet;
 use hgtime::HgTime;
@@ -196,12 +197,16 @@ impl Generator {
     }
 
     #[allow(dead_code)]
-    pub(crate) fn load_hgrc(&mut self, value: &'static str) -> Result<()> {
+    pub(crate) fn load_hgrc(
+        &mut self,
+        value: impl Into<Text> + Clone + std::fmt::Display,
+    ) -> Result<()> {
+        let value_copy = value.clone();
         let errors = self.config.parse(value, &"dynamicconfigs".into());
         if !errors.is_empty() {
             bail!(
                 "invalid dynamic config blob: '{}'\nerrors: '{:?}'",
-                value,
+                value_copy,
                 errors
             );
         }
@@ -209,8 +214,12 @@ impl Generator {
     }
 
     pub fn execute(mut self) -> Result<ConfigSet> {
-        #[cfg(feature = "fb")]
-        self._execute(fb::fb_rules)?;
+        if std::env::var("HG_TEST_DYNAMICCONFIG").is_ok() {
+            self._execute(test_rules)?;
+        } else {
+            #[cfg(feature = "fb")]
+            self._execute(fb::fb_rules)?;
+        }
         Ok(self.config)
     }
 
@@ -254,6 +263,16 @@ fn get_hg_group(tiers: &HashSet<String>, shard: u8) -> HgGroup {
     }
 }
 
+/// Rules used in our integration test environment
+fn test_rules(gen: &mut Generator) -> Result<()> {
+    if let Ok(path) = std::env::var("HG_TEST_DYNAMICCONFIG") {
+        let hgrc = std::fs::read_to_string(path).unwrap();
+        gen.load_hgrc(hgrc).unwrap();
+    }
+
+    Ok(())
+}
+
 #[cfg(test)]
 pub(crate) mod tests {
     use super::*;

eden/scm/tests/test-debugdynamicconfig.t

@@ -0,0 +1,57 @@
+#chg-compatible
+
+  $ configure modern
+
+  $ setconfig configs.loaddynamicconfig=True
+  $ export HG_TEST_DYNAMICCONFIG="$TESTTMP/test_hgrc"
+  $ cat > test_hgrc <<EOF
+  > [section]
+  > key=value
+  > EOF
+
+  $ hg init client
+  $ cd client
+
+Verify it can be manually generated
+
+  $ hg debugdynamicconfig
+  $ cat .hg/hgrc.dynamic
+  [section]
+  key=value
+  
+  $ hg config section.key
+  value
+
+Verify it can be automatically synchronously generated
+
+  $ rm .hg/hgrc.dynamic
+  $ hg config section.key
+  [1]
+  $ hg config section.key --config configs.autogeneratedynamicconfig=True
+  value
+  $ cat .hg/hgrc.dynamic
+  [section]
+  key=value
+  
+Verify it can be automatically asynchronously regenerated
+
+  $ cat > $TESTTMP/test_hgrc <<EOF
+  > [section]
+  > key=value
+  > [section2]
+  > key2=value2
+  > EOF
+  $ hg config section2.key2 --config configs.generationtime=30 # No regen, because too soon
+  [1]
+  $ sleep 1
+  $ hg status --config configs.generationtime=1 # Regen, because lower time limit
+  $ sleep 0.5 # Time for background process to complete
+  $ hg config section2.key2
+  value2
+  $ cat .hg/hgrc.dynamic
+  [section]
+  key=value
+  
+  [section2]
+  key2=value2
+