Describe the bug
Initially observed as a hangup failure when trying to evaluate nixosTests.tor:
$ nix-instantiate --expr 'with import ./. { config.contentAddressedByDefault = true; }; nixosTests.tor'
...
resolved derivation: '/nix/store/8qlkb0gm5c2pl4467hyi49249rkwzvv7-tor-da-keys-da1.drv' -> '/nix/store/c49l6h2skvr2y3y4k7xrsqj6n19yc592-tor-da-keys-da1.drv'...
# hung
Steps To Reproduce
Here is a smaller extracted example, relies just on busybox:
$ nix-build --expr '(let busybox = (with import <nixpkgs> { config.contentAddressedByDefault = true; }; pkgs.busybox); d1 = derivation {name = "d1"; builder = "${busybox}/bin/busybox"; args = ["sh" "-c" "echo $out > $out"]; system = "x86_64-linux"; __contentAddressed = true; }; r = builtins.readFile "///${d1}"; in derivation {name = "d2"; builder = "${busybox}/bin/busybox"; args = ["sh" "-c" "echo fail: ${r} > $out"]; system = "x86_64-linux"; __contentAddressed = true; })'
...
resolved derivation: '/nix/store/5zayf32zdbgpr2i6mg76zgdxr99inksz-d1.drv' -> '/nix/store/mw6aapg45xr30f00d3lp8y7lljja46w4-d1.drv'...
# hung
Expected behavior
The instantiation should not hang up and should finish (or fail).
Metadata
nix-env (Nix) 2.35pre20260407_a37db9d2+2
Additional context
Adding --debug --verbose it looks like nix is in infinite loop of trying to instantiate the same things:
$ nix-build --expr '(let busybox = (with import <nixpkgs> { config.contentAddressedByDefault = true; }; pkgs.busybox); d1 = derivation {name = "d1"; builder = "${busybox}/bin/busybox"; args = ["sh" "-c" "echo $out > $out"]; system = "x86_64-linux"; __contentAddressed = true; }; r = builtins.readFile "///${d1}"; in derivation {name = "d2"; builder = "${busybox}/bin/busybox"; args = ["sh" "-c" "echo fail: ${r} > $out"]; system = "x86_64-linux"; __contentAddressed = true; })' --debug --verbose
...
performing daemon worker op: 43
rewriting the derivation
rewriting /01dpnxgxllna85dzvw8d91s12aav3b4w1xx2a5wsyq9ml18xfkn7 as /nix/store/i1ghnpc4n7vwhihhfvlzh997la5s2y53-patchelf-static-0.18.0
rewriting /04b24c25n0jqg0wnvyb0b71p169fglnjynr60bc3fwlw7l5q22lm as /nix/store/a0hzb50yxv25rkyl7xbgj35cpch5akj4-bzip2-static-1.0.8
rewriting /0d38f6r6rrkfzr8k4g1rg5a8hqy73ydsdigbz0r34vx0lw47zzl8 as /nix/store/hyg16l6dj178dfxlhkr8ldw8wc2zss21-gnupatch-static-2.8
rewriting /0frcd89wxr7hjmx57bxcykzfh9qih0679z6mwyxsydpvi315mvx7 as /nix/store/52m99c9d9zzmbqzpkf42gdlzxhx1kq3n-coreutils-static-9.9
rewriting /0g8gdv2jicmy2dx1i2nfd7wqaanc5l49k1c1dfchxh3k94whx6g9 as /nix/store/x6ccrm6a72764hqil64jhpclds4wjxhn-xz-5.8.2
rewriting /118vbcrzdnyfrlanscg6qrqhagz4r5dqbr6vv8kgdz2ych2dgx02 as /nix/store/y7ls975p7gq1xszmz6baig0c97b9hndf-gnutar-static-1.35
rewriting /13lvqxjf66lnam09wmlq8hmkdxwhlpi7y1n2ln177l3dn2815xr6 as /nix/store/d4r1rih1w3bfvx5br8b2gzlh9882ibhd-gzip-static-1.14
rewriting /15d5bl0g1zpysljbrgb5blaibckrl7kpphf0mhy1asiazfrhzf14 as /nix/store/fhr7908hmdn4msb2b2z27djfk6q4a6rn-gnused-static-4.9
rewriting /15pizsckzjraj6nrch4xdal9pyspjwj36wkw7ynwqi7wai8b94ap as /nix/store/ad9k20qn5ddfpazzbcnypwk141r8kifp-gawk-static-5.3.2
rewriting /1bdclp2in2avp1k143yh8p9c49ws6qy4pm6ychq75h3wf17fkhr4 as /nix/store/1zndpvl4jx97l1ydjs3zyh92c2rd49i6-binutils-static-2.46.0
rewriting /1f91z5zhh1irqxpfrxs94g4wp4dba0rlswdpgg3jwfnx4nmb6h7r as /nix/store/gqsbahjmi9g6d7q5j3qm4r68m89ff41l-bash-static-5.3
rewriting /1hlvijbhphrvk6fxjhpywqqhnnfq4dm3rfzp8dyg1gkmxmzv8x5s as /nix/store/a0dchlvvbwn8x6vnh3d9jdhjkgys83f2-findutils-static-4.10.0
rewriting /1j7jczm4aj5si8i468vnlb79nccsxg7wbaiv3pmafxjfhn0lv1n0 as /nix/store/mwdiachzsag67vf49kvbxr61lc3dvahl-gnugrep-static-3.12
rewriting /1l6pwz22qs8vx98ibwys9953blx6vjvmhgca80l98qxlbmmr583x as /nix/store/6jqn0l2hf4rbqyvdhsad0h49pqbhz69y-diffutils-static-3.12
rewriting /1qblx7v0pn3pba0bbpf4v2xlpcv90gvp0ysivjwkfcm6pqq7qb7i as /nix/store/h31qj6s31sb2hvddbfx74msvf6bmqmsy-gcc-15.2.0
rewriting /1srnx68336lpzl67hjn2bc5750kkfcb4dj5skhsx0kavbw3kvpam as /nix/store/anwzxxjpkgim0n5jgvqbggrwi9yq08pd-gnumake-static-4.4.1
performing daemon worker op: 43
rewriting the derivation
rewriting /05pxj60yyqsmcfy862fy5lm0yazm8wql3ylbm02f4nhliifnmfxm as /nix/store/yj1pjc2syqq4gn6gr9jjda2sxhlhaqnk-glibc-2.42
rewriting /0fv1f95c84a9cmb76isybkfyjslx5hfy00jg7c6d4giby5w4x0wp as /nix/store/yjq8vpfhn2jfnl7gbm2s0pf2yn6mcwc8-bootstrap-stage0-stdenv-linux
rewriting /1f91z5zhh1irqxpfrxs94g4wp4dba0rlswdpgg3jwfnx4nmb6h7r as /nix/store/gqsbahjmi9g6d7q5j3qm4r68m89ff41l-bash-static-5.3
performing daemon worker op: 43
rewriting the derivation
rewriting /01dpnxgxllna85dzvw8d91s12aav3b4w1xx2a5wsyq9ml18xfkn7 as /nix/store/i1ghnpc4n7vwhihhfvlzh997la5s2y53-patchelf-static-0.18.0
rewriting /04b24c25n0jqg0wnvyb0b71p169fglnjynr60bc3fwlw7l5q22lm as /nix/store/a0hzb50yxv25rkyl7xbgj35cpch5akj4-bzip2-static-1.0.8
rewriting /0d38f6r6rrkfzr8k4g1rg5a8hqy73ydsdigbz0r34vx0lw47zzl8 as /nix/store/hyg16l6dj178dfxlhkr8ldw8wc2zss21-gnupatch-static-2.8
rewriting /0frcd89wxr7hjmx57bxcykzfh9qih0679z6mwyxsydpvi315mvx7 as /nix/store/52m99c9d9zzmbqzpkf42gdlzxhx1kq3n-coreutils-static-9.9
rewriting /0g8gdv2jicmy2dx1i2nfd7wqaanc5l49k1c1dfchxh3k94whx6g9 as /nix/store/x6ccrm6a72764hqil64jhpclds4wjxhn-xz-5.8.2
rewriting /118vbcrzdnyfrlanscg6qrqhagz4r5dqbr6vv8kgdz2ych2dgx02 as /nix/store/y7ls975p7gq1xszmz6baig0c97b9hndf-gnutar-static-1.35
rewriting /13lvqxjf66lnam09wmlq8hmkdxwhlpi7y1n2ln177l3dn2815xr6 as /nix/store/d4r1rih1w3bfvx5br8b2gzlh9882ibhd-gzip-static-1.14
rewriting /15d5bl0g1zpysljbrgb5blaibckrl7kpphf0mhy1asiazfrhzf14 as /nix/store/fhr7908hmdn4msb2b2z27djfk6q4a6rn-gnused-static-4.9
rewriting /15pizsckzjraj6nrch4xdal9pyspjwj36wkw7ynwqi7wai8b94ap as /nix/store/ad9k20qn5ddfpazzbcnypwk141r8kifp-gawk-static-5.3.2
rewriting /1bdclp2in2avp1k143yh8p9c49ws6qy4pm6ychq75h3wf17fkhr4 as /nix/store/1zndpvl4jx97l1ydjs3zyh92c2rd49i6-binutils-static-2.46.0
rewriting /1f91z5zhh1irqxpfrxs94g4wp4dba0rlswdpgg3jwfnx4nmb6h7r as /nix/store/gqsbahjmi9g6d7q5j3qm4r68m89ff41l-bash-static-5.3
rewriting /1hlvijbhphrvk6fxjhpywqqhnnfq4dm3rfzp8dyg1gkmxmzv8x5s as /nix/store/a0dchlvvbwn8x6vnh3d9jdhjkgys83f2-findutils-static-4.10.0
rewriting /1j7jczm4aj5si8i468vnlb79nccsxg7wbaiv3pmafxjfhn0lv1n0 as /nix/store/mwdiachzsag67vf49kvbxr61lc3dvahl-gnugrep-static-3.12
rewriting /1l6pwz22qs8vx98ibwys9953blx6vjvmhgca80l98qxlbmmr583x as /nix/store/6jqn0l2hf4rbqyvdhsad0h49pqbhz69y-diffutils-static-3.12
rewriting /1qblx7v0pn3pba0bbpf4v2xlpcv90gvp0ysivjwkfcm6pqq7qb7i as /nix/store/h31qj6s31sb2hvddbfx74msvf6bmqmsy-gcc-15.2.0
rewriting /1srnx68336lpzl67hjn2bc5750kkfcb4dj5skhsx0kavbw3kvpam as /nix/store/anwzxxjpkgim0n5jgvqbggrwi9yq08pd-gnumake-static-4.4.1
performing daemon worker op: 43
...
# goes on and on
Checklist
Add 👍 to issues you find important.
Describe the bug
Initially observed as a hangup failure when trying to evaluate
nixosTests.tor:Steps To Reproduce
Here is a smaller extracted example, relies just on
busybox:Expected behavior
The instantiation should not hang up and should finish (or fail).
Metadata
nix-env (Nix) 2.35pre20260407_a37db9d2+2Additional context
Adding
--debug --verboseit looks likenixis in infinite loop of trying to instantiate the same things:Checklist
Add 👍 to issues you find important.