From 39733ac3e509a374e55278463ebc29b5cedc9f09 Mon Sep 17 00:00:00 2001
From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
Date: Fri, 27 Sep 2024 15:49:02 -0500
Subject: [PATCH 1/3] nix: work around ziglang/zig#20976 and fix nix package
 builds

Because Zig does not fetch recursive dependencies when you run `zig build
--fetch` (see https://github.com/ziglang/zig/issues/20976) we need to do some
extra work to fetch everything that we actually need to build without Internet
access (such as when building a Nix package).

An example of this happening:

```
error: builder for '/nix/store/cx8qcwrhjmjxik2547fw99v5j6np5san-ghostty-0.1.0.drv' failed with exit code 1;
      la/build/tmp.xgHOheUF7V/p/12208cfdda4d5fdbc81b0c44b82e4d6dba2d4a86bff644a153e026fdfc80f8469133/build.zig.zon:7:20: error: unable to discover remote git server capabilities: TemporaryNameServerFailure
      >             .url = "git+https://github.com/zigimg/zigimg#3a667bdb3d7f0955a5a51c8468eac83210c1439e",
      >                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      > /build/tmp.xgHOheUF7V/p/12208cfdda4d5fdbc81b0c44b82e4d6dba2d4a86bff644a153e026fdfc80f8469133/build.zig.zon:16:20: error: unable to discover remote git server capabilities: TemporaryNameServerFailure
      >             .url = "git+https://github.com/mitchellh/libxev#f6a672a78436d8efee1aa847a43a900ad773618b",
      >                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      >
      For full logs, run 'nix log /nix/store/cx8qcwrhjmjxik2547fw99v5j6np5san-ghostty-0.1.0.drv'.
```

To update this script, add any failing URLs with a line like this:

```
  zig fetch <url>
```

Periodically old URLs may need to be cleaned out.

Hopefully when the Zig issue is fixed this script can be eliminated in favor
of a plain `zig build --fetch`.
---
 fetch-zig-cache.sh                        | 45 +++++++++++++++++++++++
 nix/build-support/check-zig-cache-hash.sh | 13 +++++--
 nix/package.nix                           |  3 +-
 nix/zigCacheHash.nix                      |  2 +-
 4 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 fetch-zig-cache.sh

diff --git a/fetch-zig-cache.sh b/fetch-zig-cache.sh
new file mode 100644
index 000000000..01b1e2569
--- /dev/null
+++ b/fetch-zig-cache.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+set -e
+
+# Because Zig does not fetch recursive dependencies when you run `zig build
+# --fetch` (see https://github.com/ziglang/zig/issues/20976) we need to do some
+# extra work to fetch everything that we actually need to build without Internet
+# access (such as when building a Nix package).
+#
+# An example of this happening:
+#
+# error: builder for '/nix/store/cx8qcwrhjmjxik2547fw99v5j6np5san-ghostty-0.1.0.drv' failed with exit code 1;
+#        la/build/tmp.xgHOheUF7V/p/12208cfdda4d5fdbc81b0c44b82e4d6dba2d4a86bff644a153e026fdfc80f8469133/build.zig.zon:7:20: error: unable to discover remote git server capabilities: TemporaryNameServerFailure
+#        >             .url = "git+https://github.com/zigimg/zigimg#3a667bdb3d7f0955a5a51c8468eac83210c1439e",
+#        >                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#        > /build/tmp.xgHOheUF7V/p/12208cfdda4d5fdbc81b0c44b82e4d6dba2d4a86bff644a153e026fdfc80f8469133/build.zig.zon:16:20: error: unable to discover remote git server capabilities: TemporaryNameServerFailure
+#        >             .url = "git+https://github.com/mitchellh/libxev#f6a672a78436d8efee1aa847a43a900ad773618b",
+#        >                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+#        >
+#        For full logs, run 'nix log /nix/store/cx8qcwrhjmjxik2547fw99v5j6np5san-ghostty-0.1.0.drv'.
+#
+# To update this script, add any failing URLs with a line like this:
+#
+#    zig fetch <url>
+#
+# Periodically old URLs may need to be cleaned out.
+#
+# Hopefully when the Zig issue is fixed this script can be eliminated in favor
+# of a plain `zig build --fetch`.
+
+if [ -z ${ZIG_GLOBAL_CACHE_DIR+x} ]
+then
+  echo "must set ZIG_GLOBAL_CACHE_DIR!"
+  exit 1
+fi
+
+if [ -z ${ZIG_LOCAL_CACHE_DIR+x} ]
+then
+  echo "must set ZIG_LOCAL_CACHE_DIR!"
+  exit 1
+fi
+
+zig build --fetch
+zig fetch git+https://github.com/zigimg/zigimg#3a667bdb3d7f0955a5a51c8468eac83210c1439e
+zig fetch git+https://github.com/mitchellh/libxev#f6a672a78436d8efee1aa847a43a900ad773618b
diff --git a/nix/build-support/check-zig-cache-hash.sh b/nix/build-support/check-zig-cache-hash.sh
index 2fd1ead5b..4ff88e800 100755
--- a/nix/build-support/check-zig-cache-hash.sh
+++ b/nix/build-support/check-zig-cache-hash.sh
@@ -25,16 +25,21 @@ elif [ "$1" != "--update" ]; then
   exit 1
 fi
 
-TMP_CACHE_DIR="$(mktemp --directory --suffix nix-zig-cache)"
+ZIG_GLOBAL_CACHE_DIR="$(mktemp --directory --suffix nix-zig-cache)"
+ZIG_LOCAL_CACHE_DIR="${ZIG_GLOBAL_CACHE_DIR}" 
+export ZIG_GLOBAL_CACHE_DIR
+export ZIG_LOCAL_CACHE_DIR
+
 # This is not 100% necessary in CI but is helpful when running locally to keep
 # a local workstation clean.
-trap 'rm -rf "${TMP_CACHE_DIR}"' EXIT
+trap 'rm -rf "${ZIG_GLOBAL_CACHE_DIR}"' EXIT
 
 # Run Zig and download the cache to the temporary directory.
-zig build --fetch --global-cache-dir "${TMP_CACHE_DIR}"
+
+sh ./fetch-zig-cache.sh
 
 # Now, calculate the hash.
-ZIG_CACHE_HASH="sha256-$(nix-hash --type sha256 --to-base64 "$(nix-hash --type sha256 "${TMP_CACHE_DIR}")")"
+ZIG_CACHE_HASH="sha256-$(nix-hash --type sha256 --to-base64 "$(nix-hash --type sha256 "${ZIG_GLOBAL_CACHE_DIR}")")"
 
 if [ "${OLD_CACHE_HASH}" == "${ZIG_CACHE_HASH}" ]; then
   echo -e "\nOK: Zig cache store hash unchanged."
diff --git a/nix/package.nix b/nix/package.nix
index b8d69eef9..d6c294b86 100644
--- a/nix/package.nix
+++ b/nix/package.nix
@@ -56,6 +56,7 @@
         ../vendor
         ../build.zig
         ../build.zig.zon
+        ../fetch-zig-cache.sh
       ]
     );
   };
@@ -90,7 +91,7 @@
     buildPhase = ''
       runHook preBuild
 
-      zig build --fetch
+      sh ./fetch-zig-cache.sh
 
       runHook postBuild
     '';
diff --git a/nix/zigCacheHash.nix b/nix/zigCacheHash.nix
index 92e656264..f11d67db1 100644
--- a/nix/zigCacheHash.nix
+++ b/nix/zigCacheHash.nix
@@ -1,3 +1,3 @@
 # This file is auto-generated! check build-support/check-zig-cache-hash.sh for
 # more details.
-"sha256-qFt9sC3GekfU940Gd9oV9Gcbs5MdxVMojIMbkDo3m2A="
+"sha256-JsAEfg1jp20aGz9YXG/QEp4MS5K5J5U7zFS2Orw2K/s="

From a9b04037b4adbddf33d41292aab4d9b7122d7e2f Mon Sep 17 00:00:00 2001
From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
Date: Fri, 27 Sep 2024 19:19:51 -0500
Subject: [PATCH 2/3] nix: don't require the ZIG_LOCAL_CACHE_DIR to be set

NixOS does not set this during Nix package builds. Probably Nix's
caching got in the way of detecting this on my system.
---
 fetch-zig-cache.sh                        | 6 ------
 nix/build-support/check-zig-cache-hash.sh | 2 --
 2 files changed, 8 deletions(-)

diff --git a/fetch-zig-cache.sh b/fetch-zig-cache.sh
index 01b1e2569..56b94e35d 100644
--- a/fetch-zig-cache.sh
+++ b/fetch-zig-cache.sh
@@ -34,12 +34,6 @@ then
   exit 1
 fi
 
-if [ -z ${ZIG_LOCAL_CACHE_DIR+x} ]
-then
-  echo "must set ZIG_LOCAL_CACHE_DIR!"
-  exit 1
-fi
-
 zig build --fetch
 zig fetch git+https://github.com/zigimg/zigimg#3a667bdb3d7f0955a5a51c8468eac83210c1439e
 zig fetch git+https://github.com/mitchellh/libxev#f6a672a78436d8efee1aa847a43a900ad773618b
diff --git a/nix/build-support/check-zig-cache-hash.sh b/nix/build-support/check-zig-cache-hash.sh
index 4ff88e800..ad51af2e4 100755
--- a/nix/build-support/check-zig-cache-hash.sh
+++ b/nix/build-support/check-zig-cache-hash.sh
@@ -26,9 +26,7 @@ elif [ "$1" != "--update" ]; then
 fi
 
 ZIG_GLOBAL_CACHE_DIR="$(mktemp --directory --suffix nix-zig-cache)"
-ZIG_LOCAL_CACHE_DIR="${ZIG_GLOBAL_CACHE_DIR}" 
 export ZIG_GLOBAL_CACHE_DIR
-export ZIG_LOCAL_CACHE_DIR
 
 # This is not 100% necessary in CI but is helpful when running locally to keep
 # a local workstation clean.

From 21a7e40510e1b03f56eea7ed871c81c799bc55f2 Mon Sep 17 00:00:00 2001
From: "Jeffrey C. Ollie" <jeff@ocjtech.us>
Date: Fri, 27 Sep 2024 20:40:03 -0500
Subject: [PATCH 3/3] nix: move fetch-zig-cache script into nix/build-support

---
 nix/build-support/check-zig-cache-hash.sh                  | 2 +-
 fetch-zig-cache.sh => nix/build-support/fetch-zig-cache.sh | 0
 nix/package.nix                                            | 4 ++--
 3 files changed, 3 insertions(+), 3 deletions(-)
 rename fetch-zig-cache.sh => nix/build-support/fetch-zig-cache.sh (100%)

diff --git a/nix/build-support/check-zig-cache-hash.sh b/nix/build-support/check-zig-cache-hash.sh
index ad51af2e4..49ea29ffb 100755
--- a/nix/build-support/check-zig-cache-hash.sh
+++ b/nix/build-support/check-zig-cache-hash.sh
@@ -34,7 +34,7 @@ trap 'rm -rf "${ZIG_GLOBAL_CACHE_DIR}"' EXIT
 
 # Run Zig and download the cache to the temporary directory.
 
-sh ./fetch-zig-cache.sh
+sh ./nix/build-support/fetch-zig-cache.sh
 
 # Now, calculate the hash.
 ZIG_CACHE_HASH="sha256-$(nix-hash --type sha256 --to-base64 "$(nix-hash --type sha256 "${ZIG_GLOBAL_CACHE_DIR}")")"
diff --git a/fetch-zig-cache.sh b/nix/build-support/fetch-zig-cache.sh
similarity index 100%
rename from fetch-zig-cache.sh
rename to nix/build-support/fetch-zig-cache.sh
diff --git a/nix/package.nix b/nix/package.nix
index d6c294b86..fccaf1c92 100644
--- a/nix/package.nix
+++ b/nix/package.nix
@@ -56,7 +56,7 @@
         ../vendor
         ../build.zig
         ../build.zig.zon
-        ../fetch-zig-cache.sh
+        ./build-support/fetch-zig-cache.sh
       ]
     );
   };
@@ -91,7 +91,7 @@
     buildPhase = ''
       runHook preBuild
 
-      sh ./fetch-zig-cache.sh
+      sh ./nix/build-support/fetch-zig-cache.sh
 
       runHook postBuild
     '';