From 269caa531729524915761f8a71e47e59e6a8598d Mon Sep 17 00:00:00 2001
From: Timothy DeHerrera <tim@nrdxp.dev>
Date: Thu, 12 Jan 2023 12:35:22 -0700
Subject: [PATCH 1/3] feat: read installable paths from stdin

Resolves #7437 for new `nix` commands only by adding a `--stdin` flag.

If paths are also passed on the cli they will be combined with the ones
from standard input.
---
 src/libcmd/command.hh      |  2 ++
 src/libcmd/installables.cc | 17 ++++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/libcmd/command.hh b/src/libcmd/command.hh
index b6d554aab..49c7b4f9b 100644
--- a/src/libcmd/command.hh
+++ b/src/libcmd/command.hh
@@ -128,6 +128,8 @@ struct InstallablesCommand : virtual Args, SourceExprCommand
 
     virtual bool useDefaultInstallables() { return true; }
 
+    bool readFromStdIn;
+
     std::vector<std::string> getFlakesForCompletion() override;
 
 protected:
diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index 00c6f9516..a67841bb6 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -691,6 +691,13 @@ StorePathSet Installable::toDerivations(
 
 InstallablesCommand::InstallablesCommand()
 {
+
+    addFlag({
+        .longName = "stdin",
+        .description = "Read installables from the standard input.",
+        .handler = {&readFromStdIn, true}
+    });
+
     expectArgs({
         .label = "installables",
         .handler = {&_installables},
@@ -707,10 +714,18 @@ void InstallablesCommand::prepare()
 
 Installables InstallablesCommand::load()
 {
-    if (_installables.empty() && useDefaultInstallables())
+    if (_installables.empty() && useDefaultInstallables() && !readFromStdIn)
         // FIXME: commands like "nix profile install" should not have a
         // default, probably.
         _installables.push_back(".");
+
+    if (readFromStdIn && !isatty(STDIN_FILENO)) {
+        std::string word;
+        while (std::cin >> word) {
+            _installables.emplace_back(std::move(word));
+        }
+    }
+
     return parseInstallables(getStore(), _installables);
 }
 

From df643051e282465b73fc29e3f223b4fd497137d7 Mon Sep 17 00:00:00 2001
From: Timothy DeHerrera <tim@nrdxp.dev>
Date: Thu, 12 Jan 2023 12:45:45 -0700
Subject: [PATCH 2/3] nix-store: read paths from standard input

Resolves #7437 for new `nix-store` by adding a `--stdin` flag.
---
 doc/manual/src/command-ref/nix-store.md |  5 +++++
 src/nix-store/nix-store.cc              | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/doc/manual/src/command-ref/nix-store.md b/doc/manual/src/command-ref/nix-store.md
index 31fdd7806..17cbd0461 100644
--- a/doc/manual/src/command-ref/nix-store.md
+++ b/doc/manual/src/command-ref/nix-store.md
@@ -54,6 +54,11 @@ have an effect.
     created by sequentially numbering symlinks beyond the first one
     (e.g., `foo`, `foo-2`, `foo-3`, and so on).
 
+  - <span id="opt-stdin">[`--stdin`](#opt-stdin)</span>
+
+    Read *paths…* from the standard input.
+    Useful for chaining nix-store commands.
+
 # Operation `--realise`
 
 ## Synopsis
diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index 3bbefedbe..d4218550a 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -1020,6 +1020,7 @@ static int main_nix_store(int argc, char * * argv)
     {
         Strings opFlags, opArgs;
         Operation op = 0;
+        bool readFromStdIn;
 
         parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
             Operation oldOp = op;
@@ -1078,6 +1079,8 @@ static int main_nix_store(int argc, char * * argv)
                 op = opGenerateBinaryCacheKey;
             else if (*arg == "--add-root")
                 gcRoot = absPath(getArg(*arg, arg, end));
+            else if (*arg == "--stdin" && !isatty(STDIN_FILENO))
+                readFromStdIn = true;
             else if (*arg == "--indirect")
                 ;
             else if (*arg == "--no-output")
@@ -1090,6 +1093,13 @@ static int main_nix_store(int argc, char * * argv)
             else
                 opArgs.push_back(*arg);
 
+            if (readFromStdIn && op != opImport && op != opRestore && op != opServe) {
+                 std::string word;
+                 while (std::cin >> word) {
+                       opArgs.emplace_back(std::move(word));
+                 };
+            }
+
             if (oldOp && oldOp != op)
                 throw UsageError("only one operation may be specified");
 

From 639659dec22ed0016ce83dce79ff2aa46d83b0ab Mon Sep 17 00:00:00 2001
From: Timothy DeHerrera <tim@nrdxp.dev>
Date: Sat, 11 Feb 2023 11:00:05 -0700
Subject: [PATCH 3/3] doc/manual: add release note for `--stdin` flag

---
 doc/manual/src/release-notes/rl-next.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/doc/manual/src/release-notes/rl-next.md b/doc/manual/src/release-notes/rl-next.md
index 78ae99f4b..dbd2e88f7 100644
--- a/doc/manual/src/release-notes/rl-next.md
+++ b/doc/manual/src/release-notes/rl-next.md
@@ -1,2 +1,5 @@
 # Release X.Y (202?-??-??)
 
+* Commands which take installables on the command line can now read them from the standard input if
+  passed the `--stdin` flag. This is primarily useful when you have a large amount of paths which
+  exceed the OS arg limit.