diff -r b1664f6eb650 -r fd1de908f2b4 mercurial/dispatch.py
--- a/mercurial/dispatch.py	Fri Sep 18 17:28:22 2020 +0530
+++ b/mercurial/dispatch.py	Fri Sep 18 18:52:38 2020 +0530
@@ -36,13 +36,16 @@
     help,
     hg,
     hook,
+    localrepo,
     profiling,
     pycompat,
     rcutil,
     registrar,
+    requirements as requirementsmod,
     scmutil,
     ui as uimod,
     util,
+    vfs,
 )
 
 from .utils import (
@@ -939,6 +942,29 @@
     return ret
 
 
+def _readsharedsourceconfig(ui, path):
+    """if the current repository is shared one, this tries to read
+    .hg/hgrc of shared source if we are in share-safe mode
+
+    Config read is loaded into the ui object passed
+
+    This should be called before reading .hg/hgrc or the main repo
+    as that overrides config set in shared source"""
+    try:
+        with open(os.path.join(path, b".hg", b"requires"), "rb") as fp:
+            requirements = set(fp.read().splitlines())
+            if not (
+                requirementsmod.SHARESAFE_REQUIREMENT in requirements
+                and requirementsmod.SHARED_REQUIREMENT in requirements
+            ):
+                return
+            hgvfs = vfs.vfs(os.path.join(path, b".hg"))
+            sharedvfs = localrepo._getsharedvfs(hgvfs, requirements)
+            ui.readconfig(sharedvfs.join(b"hgrc"), path)
+    except IOError:
+        pass
+
+
 def _getlocal(ui, rpath, wd=None):
     """Return (path, local ui object) for the given target path.
 
@@ -959,12 +985,14 @@
     else:
         lui = ui.copy()
         if rcutil.use_repo_hgrc():
+            _readsharedsourceconfig(lui, path)
             lui.readconfig(os.path.join(path, b".hg", b"hgrc"), path)
 
     if rpath:
         path = lui.expandpath(rpath)
         lui = ui.copy()
         if rcutil.use_repo_hgrc():
+            _readsharedsourceconfig(lui, path)
             lui.readconfig(os.path.join(path, b".hg", b"hgrc"), path)
 
     return path, lui