`ihp-new` fails on Mac OS due to Unix-domain socket path being too long

[adueck]

I was just trying to spin up a new project using ihp-new as per the Creating Your First Project guide:

On Mac OS Sequoia 15.5 with Nix and direnv installed and setup, using zsh.

% nix --version
nix (Determinate Nix 3.8.5) 2.30.2
% nix-env --install ihp-new
error: selector 'ihp-new' matches no derivations
# NOT WORKING, TRYING THE FLAKES WAY MENTIONED
% nix profile install nixpkgs#ihp-new
# THIS WORKED
... installing ...
% ihp-new blog
... working ...

We will now create your new IHP project. This may take up to 30 seconds.
Initialized empty Git repository in /Users/adam/Code/blog/.git/
error: Cannot build '/nix/store/zyhq4b019kxczkcvvbc9sf90w2f6v7m7-postgresql-simple-0.7.0.0.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/db6sbv6hggacxxzaid6sdp2apl5lkiri-postgresql-simple-0.7.0.0-doc
         /nix/store/v36dygv79hs3h4ak6xycn59n5w9ld6zm-postgresql-simple-0.7.0.0
       Last 25 log lines:
       > selecting default time zone ... UTC
       > creating configuration files ... ok
       > running bootstrap script ... ok
       > performing post-bootstrap initialization ... ok
       > syncing data to disk ... ok
       >
       > initdb: warning: enabling "trust" authentication for local connections
       > initdb: hint: You can change this by editing pg_hba.conf or using the option -A, or --auth-local and --auth-host, the next time you run initdb.
       >
       > Success. You can now start the database server using:
       >
       >     pg_ctl -D /nix/var/nix/builds/nix-build-postgresql-simple-0.7.0.0.drv-8423-1219884388/postgresql -l logfile start
       >
       > starting postgresql
       > waiting for server to start....2025-08-18 21:54:44.026 UTC [29877] LOG:  starting PostgreSQL 15.6 on aarch64-apple-darwin23.4.0, compiled by clang version 16.0.6, 64-bit
       > 2025-08-18 21:54:44.026 UTC [29877] LOG:  Unix-domain socket path "/nix/var/nix/builds/nix-build-postgresql-simple-0.7.0.0.drv-8423-1219884388/run/postgresql/.s.PGSQL.5432" is too long (maximum 103 bytes)
       > 2025-08-18 21:54:44.026 UTC [29877] WARNING:  could not create Unix-domain socket in directory "/nix/var/nix/builds/nix-build-postgresql-simple-0.7.0.0.drv-8423-1219884388/run/postgresql"
       > 2025-08-18 21:54:44.026 UTC [29877] FATAL:  could not create any Unix-domain sockets
       > 2025-08-18 21:54:44.027 UTC [29877] LOG:  database system is shut down
       >  stopped waiting
       > pg_ctl: could not start server
       > Examine the log output.
       > /nix/store/g3ikambclkcz7z9sxy1ijy8pxwbybvac-stdenv-darwin/setup: line 138: pop_var_context: head of shell_variables not a function context
       > /nix/store/g3ikambclkcz7z9sxy1ijy8pxwbybvac-stdenv-darwin/setup: line 83: pop_var_context: head of shell_variables not a function context
       > /nix/store/g3ikambclkcz7z9sxy1ijy8pxwbybvac-stdenv-darwin/setup: line 1588: pop_var_context: head of shell_variables not a function context
       For full logs, run:
         nix log /nix/store/zyhq4b019kxczkcvvbc9sf90w2f6v7m7-postgresql-simple-0.7.0.0.drv
error: Cannot build '/nix/store/gzmkmpsb1hagbfymglz02xx4lv6j9hvp-ghc-9.8.2-with-packages.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/8hdc3yymwsd2hyhyv86png0q0w2gvpds-ghc-9.8.2-with-packages
error: Cannot build '/nix/store/i33vn9nw1xwmib3mksfvlfkfhid7mir1-ihp-v1.3.0.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/09y58lxs01nx3qc16c94cmvyd4p8cmvx-ihp-v1.3.0
         /nix/store/894za6rv3mcklp0yav0aqln1c7l93iid-ihp-v1.3.0-doc
error: Cannot build '/nix/store/w5vb38cd8zl1nz4fd9q50yb2j8w6qja9-devenv-shell-env.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/8bdf0a07p1icb1cyrs96bkrd2zypdffz-devenv-shell-env

I tried to follow the Getting Started Guide exactly. Am I missing something? Or is this a bug on MacOs? I saw this earlier issue mentioning a similar error.