From 3c75ddc16b054a7dabf0710ee0a4323b4371effd Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Fri, 7 Aug 2020 14:46:00 +0200
Subject: [PATCH] nix build (and others): Force re-evaluation of cached errors
Fixes #3872.
This is a bit hacky. Ideally we would automatically re-evaluate the
failed attribute iff we need to print the error message (so in
commands like 'nix search' we wouldn't re-evaluate because we're
suppressing errors).
---
src/libexpr/eval-cache.cc | 17 ++++++++++-------
src/libexpr/eval-cache.hh | 6 ++++--
2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/src/libexpr/eval-cache.cc b/src/libexpr/eval-cache.cc
index deb32484f..46177a0a4 100644
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@@ -405,7 +405,7 @@ Value & AttrCursor::forceValue()
return v;
}
-std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name)
+std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErrors)
{
if (root->db) {
if (!cachedValue)
@@ -422,9 +422,12 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name)
if (attr) {
if (std::get_if<missing_t>(&attr->second))
return nullptr;
- else if (std::get_if<failed_t>(&attr->second))
- throw EvalError("cached failure of attribute '%s'", getAttrPathStr(name));
- else
+ else if (std::get_if<failed_t>(&attr->second)) {
+ if (forceErrors)
+ debug("reevaluating failed cached attribute '%s'");
+ else
+ throw CachedEvalError("cached failure of attribute '%s'", getAttrPathStr(name));
+ } else
return std::make_shared<AttrCursor>(root,
std::make_pair(shared_from_this(), name), nullptr, std::move(attr));
}
@@ -469,9 +472,9 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(std::string_view name)
return maybeGetAttr(root->state.symbols.create(name));
}
-std::shared_ptr<AttrCursor> AttrCursor::getAttr(Symbol name)
+std::shared_ptr<AttrCursor> AttrCursor::getAttr(Symbol name, bool forceErrors)
{
- auto p = maybeGetAttr(name);
+ auto p = maybeGetAttr(name, forceErrors);
if (!p)
throw Error("attribute '%s' does not exist", getAttrPathStr(name));
return p;
@@ -600,7 +603,7 @@ bool AttrCursor::isDerivation()
StorePath AttrCursor::forceDerivation()
{
- auto aDrvPath = getAttr(root->state.sDrvPath);
+ auto aDrvPath = getAttr(root->state.sDrvPath, true);
auto drvPath = root->state.store->parseStorePath(aDrvPath->getString());
if (!root->state.store->isValidPath(drvPath) && !settings.readOnlyMode) {
/* The eval cache contains 'drvPath', but the actual path has
diff --git a/src/libexpr/eval-cache.hh b/src/libexpr/eval-cache.hh
index afee85fa9..8ffffc0ed 100644
--- a/src/libexpr/eval-cache.hh
+++ b/src/libexpr/eval-cache.hh
@@ -9,6 +9,8 @@
namespace nix::eval_cache {
+MakeError(CachedEvalError, EvalError);
+
class AttrDb;
class AttrCursor;
@@ -92,11 +94,11 @@ public:
std::string getAttrPathStr(Symbol name) const;
- std::shared_ptr<AttrCursor> maybeGetAttr(Symbol name);
+ std::shared_ptr<AttrCursor> maybeGetAttr(Symbol name, bool forceErrors = false);
std::shared_ptr<AttrCursor> maybeGetAttr(std::string_view name);
- std::shared_ptr<AttrCursor> getAttr(Symbol name);
+ std::shared_ptr<AttrCursor> getAttr(Symbol name, bool forceErrors = false);
std::shared_ptr<AttrCursor> getAttr(std::string_view name);
--
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