Relocatable ocamlfind with sprinkles

.github/workflows/ci.yml

@@ -37,21 +37,28 @@ jobs:
         uses: ocaml/setup-ocaml@v3
         with:
           ocaml-compiler: ${{ matrix.ocaml-version }}
+          opam-disable-sandboxing: ${{ runner.os == 'macOS' && 'true' || 'false' }}
           windows-environment: ${{ matrix.os.windows_environment == '' && 'cygwin' || matrix.os.windows_environment }}
           opam-repositories: |
             default: git+https://github.com/ocaml/opam-repository.git
             archive: git+https://github.com/ocaml/opam-repository-archive.git
 
       - name: Build with make
         run: |
-          opam exec -- ${{ runner.os == 'Windows' && 'sh ' || '' }}./configure
+          opam exec -- ${{ runner.os == 'Windows' && 'sh ' || '' }}./configure -sitelib .
           echo ------------
           grep "[\\\\/]" Makefile.config
           echo ------------
           opam exec -- make all opt
 
       - name: Build and install with opam
-        run: opam pin add ocamlfind .
+        id: opam
+        env:
+          SOURCE_DATE_EPOCH: 0
+          OCAMLPARAM: ${{ runner.os == 'macOS' && '|_|cclib=-Wl,-S' || '' }}
+        run: |
+          opam pin add ocamlfind .
+          sh -c 'echo "relocatable=$(test -n "$(opam list --installed --short compiler-cloning.enabled)" && echo "true" || echo "false")" >> "$GITHUB_OUTPUT"'
 
       - name: Test the ocamlfind binary
         env:
@@ -67,3 +74,29 @@ jobs:
 
       - name: Test the toplevel plugin
         run: opam exec -- ocaml .github/workflows/toplist.ml
+
+      - name: Create second switch (relocatable)
+        if: steps.opam.outputs.relocatable == 'true'
+        shell: bash
+        env:
+          SOURCE_DATE_EPOCH: 0
+          OCAMLPARAM: ${{ runner.os == 'macOS' && '|_|cclib=-Wl,-S' || '' }}
+        run: |
+          opam switch create second --no-switch $(opam list --color=never --columns=package --short --installed ocaml | tr -d '\r')
+          opam pin add --switch=second ocamlfind .
+
+      - name: Check ocamlfind is relocatable
+        if: steps.opam.outputs.relocatable == 'true'
+        shell: bash
+        run: |
+          first="$(opam var bin | tr -d '\r')/ocamlfind${{ runner.os == 'Windows' && '.exe' || '' }}"
+          second="$(opam var --switch=second bin | tr -d '\r')/ocamlfind${{ runner.os == 'Windows' && '.exe' || '' }}"
+          sha1sum "$first" "$second"
+          if ! cmp -s "$first" "$second"; then
+            if command -v xxd > /dev/null; then
+              diff <(xxd "$first") <(xxd "$second") || true
+            else
+              diff <(od -A x -t x1 -v "$first") <(od -A x -t x1 -v "$second") || true
+            fi
+            exit 1
+          fi

.github/workflows/toplist.ml

@@ -1,8 +1,26 @@
 #use "topfind";;
 #list;;
+#require "unix";;
 #require "findlib";;
+let realpath = Filename.concat (Sys.getcwd()) "src/findlib/realpath.ml" in
+Topdirs.dir_use Format.err_formatter realpath;;
 let () =
   let ld_conf = Findlib.ocaml_ldconf () in
-  let print_line = Printf.printf "  %s\n" in
+  let print_line {Findlib.raw = raw; Findlib.eff = eff} =
+    let real = realpath eff in
+    let real =
+      if real = eff then
+        ""
+      else
+        "\n    -> " ^ real
+    in
+    let eff =
+      if raw ^ real = eff then
+        ""
+      else
+        "\n    -> " ^ eff
+    in
+    Printf.printf "  %s%s%s\n" raw eff real
+  in
   Printf.printf "Reading %s\n" ld_conf;
   List.iter print_line (Findlib.read_ldconf ld_conf);;

.gitignore

@@ -18,12 +18,14 @@ findlib.conf
 ocargs.log
 src/findlib/depend
 src/findlib/findlib_config.ml
+src/findlib/findlib_config_?.mlp
 src/findlib/fl_meta.ml
 src/findlib/ocaml_args.ml
 src/findlib/ocamlfind
 src/findlib/ocamlfind_opt
+src/findlib/realpath.ml
 src/findlib/topfind
 src/findlib/topfind.ml
-src/findlib/topfind.compat.in
+src/findlib/topfind_??.p
 tools/extract_args/extract_args
 tools/extract_args/extract_args.ml

GNUmakefile

@@ -0,0 +1,16 @@
+include Makefile.config
+
+ifeq "$(IS_RELOCATABLE)" "1"
+  HASH := \#
+  SRCDIR_ENCODED = $(subst =,%+,$(subst :,%.,$(subst %,%$(HASH),$(SRCDIR_ABS))))
+  SRCDIR_ABS_REAL := $(shell realpath $(SRCDIR_ABS) 2>/dev/null)
+  SRCDIR_REAL_ENCODED = \
+    $(subst =,%+,$(subst :,%.,$(subst %,%$(HASH),$(SRCDIR_ABS_REAL))))
+  BUILD_PATH_PREFIX_MAP ?=
+  export BUILD_PATH_PREFIX_MAP := \
+    $(BUILD_PATH_PREFIX_MAP)$\
+      :.=$(SRCDIR_ENCODED)$\
+      $(if $(SRCDIR_REAL_ENCODED),:.=$(SRCDIR_REAL_ENCODED))
+endif
+
+include Makefile

Makefile.config.pattern

@@ -3,6 +3,11 @@
 # Note that there are other files containing parts of the 
 # configuration, especially the site-lib/*/META files.
 # 
+#----------------------------------------------------------------------
+# Where is findlib being compiled:
+#----------------------------------------------------------------------
+SRCDIR_ABS=/home/user/ocamlfind
+
 #----------------------------------------------------------------------
 # Where the OCAML core is installed:
 #----------------------------------------------------------------------
@@ -21,7 +26,13 @@ OCAML_THREADS=vm
 # Where the site-lib directory will be
 #----------------------------------------------------------------------
 OCAML_SITELIB=/usr/local/lib/ocaml/site-lib
-OCAML_SITELIB_NATIVE=$(OCAML_SITELIB)
+
+#----------------------------------------------------------------------
+# For Relocatable Findlib, the path of site-lib relative to the OCaml
+# Standard Library directory. For normal Findlib, equal to
+# $(OCAML_SITELIB)
+#----------------------------------------------------------------------
+OCAML_SITELIB_FROM_STDLIB=$(OCAML_SITELIB)
 
 #----------------------------------------------------------------------
 # Where binaries and manual pages will be installed
@@ -32,8 +43,9 @@ OCAMLFIND_MAN=/usr/local/man
 #----------------------------------------------------------------------
 # The absolute location of the configuration file
 #----------------------------------------------------------------------
-OCAMLFIND_CONF=/usr/local/etc/ocamlfind.conf
+OCAMLFIND_CONF=/usr/local/etc/$(OCAMLFIND_CONF_NAME)
 OCAMLFIND_CONF_NATIVE=$(OCAMLFIND_CONF)
+OCAMLFIND_CONF_NAME=ocamlfind.conf
 
 #----------------------------------------------------------------------
 # Autolinking is usually on
@@ -67,6 +79,12 @@ INSTALL_TOPFIND=1
 #----------------------------------------------------------------------
 RELATIVE_PATHS=0
 
+#----------------------------------------------------------------------
+# Whether Relocatable Findlib is being built
+#----------------------------------------------------------------------
+IS_RELOCATABLE=0
+RELOCATABLE=
+
 #----------------------------------------------------------------------
 # Whether make install should update Makefile.packages just before
 # running