Revert "Refactor dep rewriting logic in github shims"

Summary:
X-link: facebook/buck2#782

Broke oss buck2 CI. buck2 does some path remapping that was not tested against
in the initial diff. The right way to handle this looks complex and will take
some time to implement, so reverting the changes in the interim.

Original commit changeset: 2cdf2fc1cbce

Original Phabricator Diff: D62896839

Reviewed By: zpao

Differential Revision: D63152891

fbshipit-source-id: 53aad436fdca15bece88b5ad0c12ea11390fb3f8

shim/shims.bzl

@@ -409,127 +409,64 @@ def _fix_resources(resources):
 
     fail("Unexpected type {} for resources".format(type(resources)))
 
-def strip_third_party_rust_version(x: str) -> str:
-    # When upgrading libraries we either suffix them as `-old` or with a version, e.g. `-1-08`
-    # Strip those so we grab the right one in open source.
-    if x.endswith(":md-5"):  # md-5 is the one exception
-        return x
-    xs = x.split("-")
-    for i in reversed(range(len(xs))):
-        s = xs[i]
-        if s == "old" or s.isdigit():
-            xs.pop(i)
-        else:
-            break
-    return "-".join(xs)
-
-def _recell_dep(newcell: str):
-    return lambda path, _d: newcell + "//" + path
-
-def _strip_dir(newprefix: str):
-    def _strip(path: str, d: str) -> str:
-        path = path.removeprefix(d).removeprefix("/")
-        if newprefix.endswith("/"):
-            return newprefix + path
-        else:
-            return newprefix + "/" + path
-
-    return _strip
-
-DEP_REWRITE_RULES = {
-    "fbcode": struct(
-        exact = {
-            "common/rust/shed/fbinit:fbinit": "shim//third-party/rust:fbinit",
-            "common/rust/shed/sorted_vector_map:sorted_vector_map": "shim//third-party/rust:sorted_vector_map",
-            "watchman/rust/watchman_client:watchman_client": "shim//third-party/rust:watchman_client",
-        },
-        dirs = [
-            ("buck2/facebook", lambda _path, _d: None),
-            ("buck2", _strip_dir("root//")),
-            ("common/ocaml/interop", _strip_dir("root//")),
-            ("third-party-buck/platform010/build/supercaml", _strip_dir("shim//third-party/ocaml")),
-            ("third-party-buck/platform010/build", _strip_dir("shim//third-party")),
-            ("folly", _recell_dep("folly")),
-        ],
-    ),
-    "fbsource": struct(
-        dirs = [
-            ("third-party/rust", lambda path, _pre: "shim//" + strip_third_party_rust_version(path)),
-            ("third-party", _recell_dep("shim")),
-        ],
-    ),
-    "root": struct(
-        dirs = [
-            ("folly", _recell_dep("folly")),
-        ],
-    ),
-    "third-party": struct(
-        dirs = [
-            ("", _strip_dir("shim//third-party")),
-        ],
-    ),
-}
-
-"""
-Modify a dependency target to account for being executed inside an OSS build.
-"""
-
-def _fix_dep(
-        x: str,
-        original_cell = None,
-        mapped_dirs = None) -> [
+def _fix_dep(x: str) -> [
     None,
     str,
 ]:
-    if "//" not in x:
-        # This is a local target, aka ":foo". Don't touch
+    def remove_version(x: str) -> str:
+        # When upgrading libraries we either suffix them as `-old` or with a version, e.g. `-1-08`
+        # Strip those so we grab the right one in open source.
+        if x.endswith(":md-5"):  # md-5 is the one exception
+            return x
+        xs = x.split("-")
+        for i in reversed(range(len(xs))):
+            s = xs[i]
+            if s == "old" or s.isdigit():
+                xs.pop(i)
+            else:
+                break
+        return "-".join(xs)
+
+    if x == "//common/rust/shed/fbinit:fbinit":
+        return "fbsource//third-party/rust:fbinit"
+    elif x == "//common/rust/shed/sorted_vector_map:sorted_vector_map":
+        return "fbsource//third-party/rust:sorted_vector_map"
+    elif x == "//watchman/rust/watchman_client:watchman_client":
+        return "fbsource//third-party/rust:watchman_client"
+    elif x.startswith("fbsource//third-party/rust:"):
+        return remove_version(x)
+    elif x.startswith(":"):
         return x
-
-    (cell, path) = x.split("//", 1)
-
-    if original_cell == None:
-        original_cell = read_config("oss", "original_cell", "fbcode")
-
-    if mapped_dirs == None:
-        mapped_dirs = filter(
-            lambda d: d != "",
-            read_config("oss", "mapped_dirs", "").split(" "),
-        )
-
-    if cell == original_cell:
-        # Absolute target (aka "cell//foo:bar") where the cell matches the cell the OSS project
-        # came from.
-        for d in mapped_dirs:
-            if path == d or path.startswith(d + "/") or path.startswith(d + ":"):
-                # Not only same cell, but one of this OSS project's directories!
-                # Map it to the root cell
-                return "root//" + path
-
-    if cell == "":
-        # Cell relative target (aka "//foo:bar") that may need to be mapped to a shim.
-        # Resolve the cell to properly apply rewrite rules
-        cell = native.get_cell_name()
-        if cell == "@":
-            cell = original_cell
-
-    rules = DEP_REWRITE_RULES.get(cell)
-
-    if rules == None:
-        # This cell does not have any associated rewrite rules
+    elif x.startswith("//buck2/facebook/"):
+        return None
+    elif x.startswith("//buck2/"):
+        return "root//" + x.removeprefix("//buck2/")
+    elif x.startswith("fbcode//common/ocaml/interop/"):
+        return "root//" + x.removeprefix("fbcode//common/ocaml/interop/")
+    elif x.startswith("fbcode//third-party-buck/platform010/build/supercaml"):
+        return "shim//third-party/ocaml" + x.removeprefix("fbcode//third-party-buck/platform010/build/supercaml")
+    elif x.startswith("fbcode//third-party-buck/platform010/build"):
+        return "shim//third-party" + x.removeprefix("fbcode//third-party-buck/platform010/build")
+    elif x.startswith("fbsource//third-party"):
+        return "shim//third-party" + x.removeprefix("fbsource//third-party")
+    elif x.startswith("third-party//"):
+        return "shim//third-party/" + x.removeprefix("third-party//")
+    elif x.startswith("//folly"):
+        oss_depends_on_folly = read_config("oss_depends_on", "folly", False)
+        if oss_depends_on_folly:
+            return "root//folly/" + x.removeprefix("//")
+        return "root//" + x.removeprefix("//")
+    elif x.startswith("root//folly"):
         return x
-
-    exact = getattr(rules, "exact", {}).get(path)
-    if exact != None:
-        # This cell has a direct rewrite mapping
-        return exact
-
-    for (d, f) in getattr(rules, "dirs", []):
-        if d == "" or path == d or path.startswith(d + "/") or path.startswith(d + ":"):
-            # The path matches the directory mapping, apply the rewrite rule
-            return f(path, d)
-
-    # No rules applied, do not rewrite the target
-    return x
+    elif x.startswith("//fizz"):
+        return "root//" + x.removeprefix("//")
+    elif x.startswith("shim//"):
+        return x
+    elif x.startswith("prelude//"):
+        return x
+    else:
+        fail("Dependency is unaccounted for `{}`.\n".format(x) +
+             "Did you forget 'oss-disable'?")
 
 def _fix_dep_in_string(x: str) -> str:
     """Replace internal labels in string values such as env-vars."""
@@ -553,16 +490,6 @@ def _assert_eq(x, y):
         fail("Expected {} == {}".format(x, y))
 
 def _test():
-    _assert_eq(_fix_dep("//:foo", "fbcode", []), "//:foo")
-    _assert_eq(_fix_dep("fbcode//common/rust/shed/fbinit:fbinit"), "shim//third-party/rust:fbinit")
-    _assert_eq(_fix_dep("fbcode//buck2/foo:bar"), "root//foo:bar")
-    _assert_eq(_fix_dep("fbcode//abc/foo:bar", "fbcode", []), "fbcode//abc/foo:bar")
-    _assert_eq(_fix_dep("fbcode//folly:bar", "fbcode", []), "folly//folly:bar")
-    _assert_eq(_fix_dep("fbcode//folly/foo:bar", "fbcode", []), "folly//folly/foo:bar")
-    _assert_eq(_fix_dep("fbcode//folly:bar", "fbcode", ["folly"]), "root//folly:bar")
-    _assert_eq(_fix_dep("fbcode//folly/foo:bar", "fbcode", ["folly"]), "root//folly/foo:bar")
-    _assert_eq(_fix_dep("fbsource//third-party/rust:derive_more-1"), "shim//third-party/rust:derive_more")
-    _assert_eq(_fix_dep("fbsource//third-party/foo:bar"), "shim//third-party/foo:bar")
-    _assert_eq(_fix_dep("third-party//foo:bar"), "shim//third-party/foo:bar")
+    _assert_eq(_fix_dep("fbsource//third-party/rust:derive_more-1"), "fbsource//third-party/rust:derive_more")
 
 _test()