Backport PR #13523: [envars] honor file "coq_environment.txt"

INSTALL.md

@@ -99,3 +99,13 @@ dependencies...) as Coq.  Distribution of pre-compiled plugins and
 Coq version compiled with the same OCaml toolchain.  An OCaml setup
 mismatch is the most probable cause for an `Error while loading ...:
 implementation mismatch on ...`.
+
+coq_environment.txt
+-------------------
+Coq binaries which honor environment variables, such as `COQLIB`, can
+be seeded values for these variables by placing a text file named
+`coq_environment.txt` next to them. The file can contain assignments
+like `COQLIB="some path"`, that is a variable name followed by `=` and
+a string that follows OCaml's escaping conventions. This feature can be
+used by installers of binary package to make Coq aware of its installation
+path.

lib/envars.ml

@@ -12,7 +12,37 @@ open Util
 
 (** {1 Helper functions} *)
 
-let getenv_else s dft = try Sys.getenv s with Not_found -> dft ()
+let parse_env_line l =
+  try Scanf.sscanf l "%[^=]=%S" (fun name value -> Some(name,value))
+  with _ -> None
+
+let with_ic file f =
+  let ic = open_in file in
+  try
+    let rc = f ic in
+    close_in ic;
+    rc
+  with e -> close_in ic; raise e
+
+let getenv_from_file name =
+  let base = Filename.dirname Sys.executable_name in
+  try
+    with_ic (base ^ "/coq_environment.txt") (fun ic ->
+      let rec find () =
+        let l = input_line ic in
+        match parse_env_line l with
+        | Some(n,v) when n = name -> v
+        | _ -> find ()
+      in
+        find ())
+  with
+  | Sys_error s -> raise Not_found
+  | End_of_file -> raise Not_found
+
+let system_getenv name =
+  try Sys.getenv name with Not_found -> getenv_from_file name
+
+let getenv_else s dft = try system_getenv s with Not_found -> dft ()
 
 let safe_getenv warning n =
   getenv_else n (fun () ->
@@ -145,7 +175,7 @@ let coqpath =
 
 (** {2 Caml paths} *)
 
-let ocamlfind () = Coq_config.ocamlfind
+let ocamlfind () = getenv_else "OCAMLFIND" (fun () -> Coq_config.ocamlfind)
 
 (** {1 XDG utilities} *)
 

test-suite/dune

@@ -8,6 +8,10 @@
  (targets libpath.inc)
  (action (with-stdout-to %{targets} (run ./ocaml_pwd.exe -quoted ../../install/%{context_name}/lib/coq/ ))))
 
+(rule
+ (targets bin.inc)
+ (action (with-stdout-to %{targets} (run ./ocaml_pwd.exe -quoted -trailing-slash ../../install/%{context_name}/bin/ ))))
+
 (rule
  (targets summary.log)
  (deps
@@ -44,4 +48,4 @@
    ; %{bin:fake_ide}
  (action
   (progn
-   (bash "make -j %{env:NJOBS=2} BIN= COQLIB=%{read:libpath.inc} PRINT_LOGS=1 UNIT_TESTS=%{env:COQ_UNIT_TEST=unit-tests}"))))
+   (bash "make -j %{env:NJOBS=2} BIN=%{read:bin.inc} COQLIB=%{read:libpath.inc} PRINT_LOGS=1 UNIT_TESTS=%{env:COQ_UNIT_TEST=unit-tests}"))))

test-suite/misc/coq_environment.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+
+export COQBIN=$BIN
+export PATH=$COQBIN:$PATH
+
+TMP=`mktemp -d`
+cd $TMP
+
+cat > coq_environment.txt <<EOT
+# we override COQLIB because we can
+COQLIB="$TMP/overridden" # bla bla
+OCAMLFIND="$TMP/overridden"
+FOOBAR="one more"
+EOT
+
+cp $BIN/coqc .
+cp $BIN/coq_makefile .
+mkdir -p overridden/tools/
+cp $COQLIB/tools/CoqMakefile.in overridden/tools/
+
+unset COQLIB
+N=`./coqc -config | grep COQLIB | grep /overridden | wc -l`
+if [ $N -ne 1 ]; then
+  echo COQLIB not overridden by coq_environment
+  coqc -config
+  exit 1
+fi
+N=`./coqc -config | grep OCAMLFIND | grep /overridden | wc -l`
+if [ $N -ne 1 ]; then
+  echo OCAMLFIND not overridden by coq_environment
+  coqc -config
+  exit 1
+fi
+./coq_makefile -o CoqMakefile -R . foo > /dev/null
+N=`grep COQMF_OCAMLFIND CoqMakefile.conf | grep /overridden | wc -l`
+if [ $N -ne 1 ]; then
+  echo COQMF_OCAMLFIND not overridden by coq_environment
+  cat CoqMakefile.conf
+  exit 1
+fi
+
+export COQLIB="/overridden2"
+N=`./coqc -config | grep COQLIB | grep /overridden2 | wc -l`
+if [ $N -ne 1 ]; then
+  echo COQLIB not overridden by COQLIB when coq_environment present
+  coqc -config
+  exit 1
+fi
+
+rm -rf $TMP
+exit 0

test-suite/ocaml_pwd.ml

@@ -1,7 +1,26 @@
+open Arg
+
+let quoted = ref false
+let trailing_slash = ref false
+
+let arguments = [
+  "-quoted",Set quoted, "Quote path";
+  "-trailing-slash",Set trailing_slash, "End the path with a /";
+]
+let subject = ref None
+let set_subject x =
+  if !subject <> None then
+    failwith "only one path";
+  subject := Some x
+
 let _ =
-  let quoted = Sys.argv.(1) = "-quoted" in
-  let ch_dir = Sys.argv.(if quoted then 2 else 1) in
-  Sys.chdir ch_dir;
+  Arg.parse arguments set_subject "Usage:";
+  let subject =
+    match !subject with
+    | None -> failwith "no path given";
+    | Some x -> x in
+  Sys.chdir subject;
   let dir = Sys.getcwd () in
-  let dir = if quoted then Filename.quote dir else dir in
+  let dir = if !trailing_slash then dir ^ "/" else dir in
+  let dir = if !quoted then Filename.quote dir else dir in
   Format.printf "%s%!" dir

tools/coq_makefile.ml

@@ -216,7 +216,7 @@ let generate_conf_coq_config oc =
   section oc "Coq configuration.";
   let src_dirs = Coq_config.all_src_dirs in
   Envars.print_config ~prefix_var_name:"COQMF_" oc src_dirs;
-  fprintf oc "COQMF_WINDRIVE=%s\n" (windrive Coq_config.coqlib)
+  fprintf oc "COQMF_WINDRIVE=%s\n" (windrive (Envars.coqlib()))
 ;;
 
 let generate_conf_files oc